Talk:Technetium/Archive 1

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Archive 1

Archive 2

red link

Under production, there is a red link to Nuclear Fuel Rod, could that instead link to Nuclear Control Rod? Magicmonster 02:45, 8 September 2005 (UTC)

Tungsten redux

according to Oak Ridge http://www.ornl.gov/sci/isotopes/s_w.html, as well as Knoll's chart of the nuclides, unless someone can back up that tungsten as no stable isotopes, I intend to fix this entry in the near future. (66.109.40.54)

The article is quite clear that tungsten's status of stability depends on the definition. How would you fix that? Femto 11:43, 26 October 2005 (UTC)

Source of beta rays?

Under the applications technetium is listed as a valuable source of beta rays. What is the actual application here? What makes technetium particularly suitable? Jan van Male 04:18, 2 May 2005 (UTC)

Well, I have no conclusive answer yet, but you can look at [1] and [2]. I think the reasons it is chosen are probably:

You can make it cheaply and easily - it's obtained from reactor waste without without isotope separation
It's a pure beta emitter, and is very consistent about it - almost every decay produces exactly one beta, all with the same energy.

[3] is also interesting. --Andrew 05:05, May 2, 2005 (UTC)

The NIST also offers a standardized technetium-99 solution [4]. --Andrew 05:28, May 2, 2005 (UTC)

Ah. Tracked it down. This is a good book, I'll borrow it and see what I can find. --Andrew 21:11, May 2, 2005 (UTC)

I think that as a standard that ⁹⁹Tc has some potential, but as a standard source I think that ¹⁴C in the form of a polymer puck would be better for many applications. For an industrial source or medical source I would suggest ⁹⁰Sr for most applications.Cadmium 23:10, 27 December 2005 (UTC)

Inote citations

Would anyone have any serious objections to converting the {{inote}} "invisible citations" over to the modern cite.php style, so that they are actually useful? The inote template appears to be deprecated these days, anyway. Anville 19:04, 10 June 2006 (UTC)

I went ahead and did this (being either bold or foolhardy), fixing a few other things along the way. Anville 20:35, 10 June 2006 (UTC)

Nuclear Stability

I understand that Promethium and Technetium are radioactive due in part to a rule that states a nucleus with an odd number of neutrons or protons is less stable than those with an even number. This has something to do with particle pairing, where a pair of like particles is at a lower energy state then they are seperately. Is there a lesser rule for those with particles matched up in 3's or 5's? The reason I ask this is both Tc and Pm have prime atomic numbers as well. —The preceding unsigned comment was added by Jokem (talk • contribs) .

Nope, prime numbers have nothing to do with it. It's just a coincidence. The odd and even pattern exists because protons and neutrons have spin which can be either up or down, and if they form up-down pairs then the spins cancel out and the energy is lower. (The ground state of every even-even nucleus is 0⁺, meaning zero spin, positive parity.) There's nothing similar for 3s or 5s. —Keenan Pepper 05:24, 30 September 2006 (UTC)

I also noted that Promethium would be right below Technetium if the Rare Earths were put underneath the Transition elements. That is, Promethium is the same number of elements from the left hand edge as Technetium. Just blind chance?

Article changed over

Article changed over to new Wikipedia:WikiProject Elements format by maveric149. Elementbox converted 11:54, 6 July 2005 by Femto (previous revision was that of 07:10, 6 July 2005).

Information Sources

Some of the text in this entry was rewritten from Los Alamos National Laboratory - Technetium. Additional text was taken directly from the Elements database 20001107 (via dict.org), and WordNet (r) 1.7 (via dict.org). Data for the table were obtained from the sources listed on the subject page and Wikipedia:WikiProject Elements but were reformatted and converted into SI units.

99 vs 99m

Which is it?

The article contradicts itselft: Tc-99 is used as a gamma ray-free source of beta rays, from the introduction.

It well suited to the role because it emits readily detectable 140 keV gamma rays, it does not emit beta radiation, from the nuclear medicine section.

Which is right?

Comatose51 04:15, 2 Jun 2005 (UTC)

They are both right - the isotope Tc99 is the beta emitter, the isotope Tc99m is the pure gamma emitter. --AjAldous 12:28, 2 Jun 2005 (UTC)

I'm used to isotope refering only to the number of neutrons. If there are two different isotopes of the same element (i.e., same # of protons) with 99 nucleons each, is the difference between them based on packing within the nucleus or something? What does the "m" designation signify?--Joel 21:38, 2 Jun 2005 (UTC)

Never mind. I failed read the whole article before posting that stupid question. It was fun to learn about nuclear_isomerism. Perhaps you can say "isomer" rather than "isotope" to avoid causing that kind of confusion in the future? The one problem I have is that, in any sample of Tc99m for use as a "pure" gamma source, its reaction product Tc99 will be present to produce beta radiation.

The difference in half-lives mean that a quite strong Tc-99m gamma source will turn into a quite weak Tc-99 beta source - that's why we don't worry about the Tc-99 left in the body after a Tc-99m scan. (I think it is also mostly eliminated pretty quickly, but I couldn't find a clear answer). --Andrew 22:25, Jun 3, 2005 (UTC)

I think it behaves a lot like Manganese, and is flushed that way.

Can we perhaps explain it a little better? I'm not a physicists or a chemist but I have a strong interest in science. I was confused by the article and I doubt I'm alone.Comatose51 04:13, 3 Jun 2005 (UTC)

Just think about it people. The body is constantly flushing out any substance, this amount is measured as a biological half-life. I can't imagine it being more than 70 years (most are on the order of days) at the absolute upper limit, it should be identical for Tc-99m (I can't find either number). However, it takes 211000 years for Tc-99 to release half its radiation. Even if the radiation stuck around in your body forever, you would be dead long, long before any harmful effects would come to you. And I plan on living to be 1000 years old ;) You would probably get hundreds of times the radiation dose from the naturally occuring K-40 in your body over a lifetime. --metta, The Sunborn 00:32, 4 Jun 2005 (UTC)

The beginning of the article should address the different half-lives in the text, so that when I, the reader, see a bunch of nuke med stuff saying that the half-life is 6 hours, I won't freak when I read

Industrial Technetium-99 decays almost entirely by beta decay, emitting beta particles with very consistent low energies and no accompanying gamma rays. Moreover, its very long half-life means that this emission decreases very slowly with time.

I swear I must have smoked something, it's right in the beginning of the nuke med section, duh. Also as a note to Sunborn, longer half-lives aren't any safer. You aren't dead long long before any ill effects. Instead, you end up like the Radium dial painters. You can wiggle a Geiger counter over their graves and still get a reading : ) (Gaviidae) 82.93.133.130 16:45, 28 November 2006 (UTC)

Dogs?

The 'Helpful Tips' section includes this text: "Technetium plays no natural biological role and is not normally found in the human body. However, it does interesting things to dogs." The last sentence is unnecessarily cryptic and provocative. Please remove it, or explain with specific biological facts. As it stands, this comment is simply unnecessary.

The last sentence is probably a joke reaction to the "no biological role... in the human body." 82.93.133.130 17:04, 28 November 2006 (UTC)

natural vs. artificial

Wait a minute, if technetium exists in the Earth's crust and in red supergiant stars, why is it labeled an artificial element? The name and the fact that it was discovered from a gap in the periodic table both state that it was artificial, despite the fact that it can be found naturally. AstroHurricane001 00:48, 5 December 2006 (UTC)

This is because it was created artificially before it was found naturally in the earths crust. In fact, it was the first time a new element was created by nuclear means. Jokem 00:25, 26 January 2007 (UTC)

Rewording

This sentence might want to be reworded.

The researchers instead named element 43 after the Greek word technètos, meaning "artificial", since it was the first element to be artificially produced.

The first element to be artificially produced could arguably be Oxygen, as it was made by Rutherford when he irradiated Nitrogen. I am not sure how to reword it though.

Maybe

The researchers instead named element 43 after the Greek word technètos, meaning "artificial", since it was the first element to be discovered by artificial means.

I think we need a word that is a hybrid between 'discovered' and 'created'. -- Lowest atomic nr that needed to be articially produced? I like it is on the same place as promethium, i like the spin part too, cudnt we make more pairings up down or down up? who realised it wouldnt be as fiery as promethium seems the question. This seems to relate chemical stability substitution models in the peractinide to radioactive nuclei insofar they predict the same.There seems to be a bit more to the subject of toxity , i would guess because of the difficultys in refraction, certainly when wastedeposit is the matter we dont speak about the 50 grams of natural technesium that evolved over 100000's of years in congo 500 mtr underground anyway?(in effect the much larger quantitys, human error and corruption and the security you can hardly do general predictions over geological behaviour so you cud err. in choice of locations, kind of like the factor quantity turns the factor coincedence into another topic?, i cant bother but the line of thought permeates so much of this kongo bed transactiniums matter it seems needlesly subjective to still mention why you want to put things so straight over 50 grams of natural technetium.) 80.57.243.16 16:56, 19 March 2007 (UTC)

Nuclear weapons?

Technetium has recently been investigated for use in nuclear weapons since it has properties that uranium doesn't have, such as a radial isotopical emmission.^{[citation needed]} Research into the use of technetium in nuclear weapons is curently in early stages.^{[citation needed]} However, technetium is less abundant that uranium and therefore may be combined with uranium or plutonium in a nuclear warhead.

This doesn't make any sense. What is radial isopical emmission supposed to mean? —Keenan Pepper 21:02, 8 September 2006 (UTC)

You bet it is less abundant. It is exists in trace amounts in the earths crust and has to be made in the lab.

So does plutonium. But that doesn't stop people from making nukes. Also, this still does not answer the question as to what "radial isotopical emission" means, either. Google turned up a big zero for the number of hits for this. mike4ty4 06:20, 19 April 2007 (UTC)

Boiling point

The boiling point in the chembox is different from the boiling point in the german wikipedia (4538 K/ 5150K). What is the right one? Is the pressure different for the two measurings? Grrahnbahr 19:50, 19 June 2007 (UTC)

Corrosion inhibitor?

(moved here)
Is ammonia pertechnate alloyed into the steel, painted on as a coating, or mixed in with whatever is run through the steel? Can it be mixed in with anything, or only with distilled water? Surely technetium is hideously expensive, which probably also limits its use. --Andrew 02:22, Apr 23, 2005 (UTC)

Everything on the web seems to be copied from the same place we got it. I found one book review whose Google description appears to indicate that the book it is about mentions the fact. Also a patent application, unintelligible of course. Bleagh. --Andrew 15:18, Apr 26, 2005 (UTC)

The CRC Handbook (under The Elements) is almost word-for-word what the LANL article says. Since the LANL article quotes it as a source, I'm a little nervous about copyright violation - but the whole Net has copied the LANL under the impression that the material was in the public domain. In any case, there's no more information there, although somehow it sounds more authoritative. Double bleagh. --Andrew 15:47, Apr 26, 2005 (UTC)

For later reference, the book review search hit was for "Angewandte Chemie International Edition in English Volume 7, Issue 1 , Pages 84 - 84; H. Grünewald, Book Review: Nobel Lectures Chemistry 1901-1921 and 1922-1941", in case the corresponding page goes where all Intellectual Property finally goes to die. The Google result is/was:

[PDF] Book Review: Nobel Lectures Chemistry 1901-1921 and 1922-1941
... and scientifically remarkable inhibition of corrosion exhibited. by pertechnate
ions. Nevertheless, the book assists the reader ...
http://doi.wiley.com/10.1002/anie.196800843

It looks like it's about a collection of lectures which are traditionally given by the Nobel prize winners. A search for "pertechnate" at http://nobelprize.org/ returns nothing relevant though. Nothing for "Grünewald" and/or "pertechnate" at Amazon.com either. If anybody has access to Angewandte Chemie/Applied Chemistry, they may find out which H. Grünewald has to say about what. Also, the period after "exhibited" has to mean something, since "exhibited by pertechnate" doesn't get a hit.

The patent, in one of the more intelligible sentences (undoubtedly by accident), mentions that salt anions (pertechnate among them) provide corrosion protection, but who knows where they got that from... Femto 19:43, 28 Apr 2005 (UTC)

Oh, this is great! Turns out McGill pays for access to this junk, so I got to read the book review. Let me quote some relevant pieces:

The chemistry of technetium and rhenium By R. D. Peacock, [...] 1965 [...]however, various omissions have been made, even in the better documented[sic] chemistry of technetium. For example, one searches in vain for information concerning the technically and scientifically remarkable inhibition of corrosion exhibited by pertechnate ions.[...]

So the specialized reference doesn't mention it? --Andrew 03:43, Apr 29, 2005 (UTC)

Sweet! Femto 13:02, 29 Apr 2005 (UTC)

I don't understand why a pertechnate ion (with an oxidation state of 7+) would prevent corrosion. I can see how unoxidised Tc can prevent corrosion by competition: instead of oxidising Fe we get a preferred oxidation of Tc (which in turn may lead to pertechnate ions). Jan van Male 18:42, 27 Apr 2005 (UTC)

I don't get it either, and the only references I've seen are quoting the LANL article we got it from; the LANL article got it from the CRC handbook, which provides no explanation at all. There's a ~~discussion~~record of my fruitless searching above. --Andrew 19:17, Apr 27, 2005 (UTC)

Fruitless indeed. I've thrown everything at Google (and a little bit at Yahoo and AlltheWeb too), from "steel pertechnate", over "TCO4 steel corrosion", "pertechnate anions", "technetium iron complex", "technetium austenitic", "technetium reactor circuit water", to "steel masurium", heck, I've even tried "сталь технеций". I hereby solemny swear that I shall never use a search engine again, should the source of this information turn out to be easily found on the Net.

The relevant quote from the Handbook of Chemistry and Physics, CRC Press, is:

>> The element is a remarkable corrosion inhibitor for steel. It is reported that mild carbon steels may be effectively protected by as little as 55 ppm of KTcO₄ in aerated distilled water at temperatures up to 250°C. This corrosion protection is limited to closed systems, since technetium is radioactive and must be confined.

So apart from a vague second-degree mention from somewhere between 1937-1968, which may even be about the original source, or which means something completely different—this appears to be the only, single concrete source of this factoid and every occurence of it which uses the "remarkable" and "is reported" phrasings. And which says 55 ppm by the way, not five as is stated by the article and by WebElements:

>> ammonium pertechnate, NH₄TcO₄, is a specialist corrosion inhibitor for steel. Mild carbon steels are protected by 5 ppm of KTcO₄ in aerated distilled water at temperatures up to 250°C. This corrosion protection is limited to closed systems, since technetium is radioactive

Ammonium pertechnate? Potassium pertechnate? We may be off by an order of magnitude? I'm not the only one thinking the corrosion factoid should be removed from the article, until our references have fought it out, right? Femto 19:43, 28 Apr 2005 (UTC)

Yes, I agree about the removal. The only original source (the CRC article) seems rather outdated/inaccurate in many other ways. Aside from the hard time we have checking whether any corrosion protection can indeed be provided by technetium (or one of its ions), we have no source mentioning any actual use of technetium in this way. This is probably most important: if it isn't used, it is not notable and hence not encyclopedic. So, removed, at least for now... Jan van Male 23:43, 28 Apr 2005 (UTC)

Hear hear. Now all those avid wikipedia readers won't be buying technetium for their pipes in vain. (At least they know how much it costs!) --Andrew 03:43, Apr 29, 2005 (UTC)

In the interest of beating a dead horse, my local library has this fluffy little piece of bedtime reading; I'll see if I can drop by and check it out tomorrow. --Andrew 03:58, Apr 29, 2005 (UTC)

So, we have three books on the chemistry of technetium in our library. Let's see what they say.

Peacock, The Chemistry of Technetium and Rhenium, Elsevier Publishing Company, 1966:
- Mentions that pertechnate is oxidising, but says nothing about corrosion either in the chapter on pertechnates or in the index.
Schwochau, Klaus, Technetium, Wiley-VCH 2000, ISBN 3-527-29496-1
- Aha! A one-page section entitled "Pertechnate as an inhibitor of corrosion". Noted in 1952; TcO4- in aqueous soultions for the protection of iron and carbon steels. 5x10^-5 M TcO4- would do it; this is one-tenth the concentration of CrO4- that would achieve the same effect. Test specimen uncorroded after 20 years (!) exposure at Ph 6. Disrupted by the presence of other ions in solution. It works by some mysterious process; a very thin layer (2.2x10^14 atoms/cm2, about a tenth of a monolayer) of mixed hydrous iron and hydrous technetium oxide is formed, but technetium oxide won't do it alone. Still not completely understood. Refers to a collection of papers by Cartledge in the 50s and 60s. Mentions that it was proposed (in the 60s) to be used in steam-generating nuclear reactors.
Rard, Joseph, et. al. Chemical Thermodynamics of Technetium, Elsevier, 1999, ISBN 0-444-50378-1
- No mention, although they refer (somewhat critically) to Cartledge's work; they mention that he derived '"corrosion potentials"', which they always mention in quotes.

So: the effect seems to be real, but not used even when radiation didn't worry people much, and poorly understood. Nevertheless, I think I'll put in something about it, since it's mentioned on every other web source, usually word-for-word what the CRC handbook says. If we don't have it, somebody will come along and put it in. --Andrew 20:13, May 2, 2005 (UTC)

May this reference research be recognized as the great deed that it is for the Web. (2.2 atoms per m² can't be right though, can it?) I assume the molarity unit "M" that is used with the 5x10^-5 is a direct quote from the book? If so, it can/should be changed to mol/L in the article at the next opportunity.

Er. No, it's not. I fixed the typo above. I'm pretty sure M molarity in mol/L, but the book doesn't seem to say.

It might be an interesting project to keep an eye on the usual web sources and see when or if they update their information.--Andrew 21:09, May 3, 2005 (UTC)

Interestingly, using a mass of 163 g/mol for TcO4 ions, times 5e-5 mol/L, that's about 8 mg/L, which is neither 5 or 55 ppm (mass). Tc alone with 4.9 would fit the 5, but this value specifically refers to KTcO4. Neither does anything seem to fit with the 55.5 mol/L for water. I take that as another point in case to mistrust any source that gives "ppm" concentrations without telling explicitly which part is meant of what. Femto 17:17, 3 May 2005 (UTC)

Yes, well, webelements is pretty bad; too bad we used it for all our articles. Somebody with some time on their hands should go through the online CRC handbook (am I getting that through McGill?) and fix all our numbers to reliable ones, possibly with footnotes to explicitly specify conditions. --Andrew 21:09, May 3, 2005 (UTC)

Tried a little too hard to make it sound ceremonial, didn't I? I consider WebElements to be one of (the?) most reliable resources on the free Web, partly better than CRC alone. It's without cynism when I say that your real-world research made Wikipedia's info even better than that, because now there is a primary reference behind the number. You have to admit that values with ambiguous ppm concentrations do tend to mutate into facts of unknown meaning and origin. Yes, it's good to specify conditions, and two sources are always better than one, why? Femto 11:47, 4 May 2005 (UTC)

Well, there may not be anything better, but, for example, the molar volume fiasco happened because they don't specify under what conditions their numbers apply. Well, with luck we can go through the list of elements one-by-one and bring them up to featured quality, fixing the numbers in the process. --Andrew 13:37, May 4, 2005 (UTC)

Wow, good job. If this information has reached a consensus state, would someone mind including it in the corrosion article? There's a thin little subsection on inhibitors, and this weird example would be a fun addition. A corrosion inhibitor article would also be a place to put the full information on passivating film layers, and I would help collaborate on fleshing it out with more mundade examples. On a slightly related note, if anyone could upload an open-source Pourbaix diagram, I would have a lot of uses for it.--Joel 22:02, 2 Jun 2005 (UTC)

Dear All,

I am sure that TcO4- is an anodic corrosion inhibitor which will function the same way as chromate or molybdate. In answer to Jan van Male these high valent metal complexes are able to inhibit corrosion by preventing the anodic reaction (metal oxidation) from occuring. These anodic inhibitors work by forming a passive film on the steel surface. The high valent metal complexes will be reduced by the metal surface, by this chemical reaction will be formed a insoluble Tc/Cr/Mo compound which will stick to the surface and block the active sites at which the corrosion would otherwise occur at.

This chemistry can be used in a slightly different way, by placing a large surface area of a steel or iron in contact with a solution of pertechnate or chromate can be used as a means of removing the Tc or Cr from the solution.

Please see the following references which are close to primary sources and are quite definative, if you want more I can dig out more references.

As an alternative, activated carbon can be used to remove TcO4- from water

http://www.lbl.gov/Education/CSEE/cup/abstracts/SU04_Truong.html

Cadmium 20:39, 27 December 2005 (UTC)

Can't say anything of importance since this definitely is where my chemistry ends, but thanks for the links! Femto 21:31, 27 December 2005 (UTC)

Mario: As said above, Tc has some similar properties to Mo, Ru, Re, so the corrosion inhibition relates to the other elements too, and some of them are used on that way. But it is a very exotic use of a very exotic element and it is worth to be on a side-note :)

Simple explanation could be that the TcO4- is chemically stable and not acidic enough, so that a KTcO4 salt solution exhibits caustic reaction (pH factor). —Preceding unsigned comment added by 84.47.97.12 (talk) 15:58, 18 October 2007 (UTC)

Mario: I found another link indirectly supporting this, quote: " It is generally known, that the number of inorganic corrosion inhibitor species available for chromate replacement is limited essentially to a few, and specifically to MoO4--, PO4---, BO2-, Si04--and NCN-. As a consequence, all commercial non-chromate corrosion inhibitor pigments are molybdates, phosphates, borates, silicates or cyanamides, or combinations of these compounds. In comparison to Cr04--, inherent limitations of their corrosion preventing mechanism render these above-specified species less effective inhibitors of corrosion, in general, and specifically of atmospheric corrosion of aluminum."

So radioactive paint with TcO4-- ions would be even better than with molybdenate or chromate ions. Chromating is used to passivate metals and to protect from corriosion, the same can be done with salts of other elements, like Mo, Tc, Si, B, P.

http://www.wipo.int/pctdb/en/wo.jsp?IA=WO2002092880&DISPLAY=DESC

Corrosion of steel takes place only on grain boundaries and on boundaries of different elements - Fe and C form electric battery in electrolyte and accelerate the corrosion. If you plug these spots by any means, the corrosion is stopped. That explains why only little TcO4-- salts was needed.

Question from reader's point of view

"Technetium plays no natural biological role and is not normally found in the human body."

This may be a stupid, but I'm slightly confused by "not normally found in the human body." Does that mean personnel who come in to contact have it inside their body? THROUGH FIRE JUSTICE IS SERVED! 02:18, 16 November 2007 (UTC)

That would be a yes depending on the method of exposure and of course the isotope.GreatMizuti 13:00, 16 November 2007 (UTC)

Technetium 2,8,18,13,2. looks very similar to Manganese 2,8,13,2. and we know that shellfish, lobsters etc. absorb it. "Manganese is an essential trace nutrient in all forms of life" The rat tests were conducted over a few weeks. indicating no long term tests. We are well aware of cheque-book pseudo-science! where clinical trials are deliberately engineered to produce the desired conclusions. It might be wise to subject these rat tests to peer review? Without Manganese, our bones would be very brittle! we know that Strontium will replace Calcium preferentially, due to it's similar electron configuration. Technetium does not occur in nature, yet marine life uptake is ubiquitous. The precautionary principle may apply here? and a systematic review may be justified?

References

Jas. Lewis Howe (1909). "Recent Work in Inorganic Chemistry" (^{[dead link]}). Journal of the American Chemical Society. 31 (12): 1284–1305. doi:10.1021/ja01942a006. Gives the original place of the work of Ogawa.

Frederik A. A. de Jonge, Ernest K. J. Pauwels (1996). "Technetium, the missing element". Zeitschrift European Journal of Nuclear Medicine and Molecular Imaging. 23 (3): 336–344. doi:10.1007/BF00837634. gives a good overview of the whole story.--Stone (talk) 14:27, 9 March 2008 (UTC)

"Could find use" - clarify please

The last sentence of the first paragraph says technetium "could find use" in a certain application. Is it being used? Is there evidence that it will be used? If not, the sentence might be original research. 71.174.226.117 20:33, 15 October 2007 (UTC)

There are a couple of patents that mention Technetium as a corrosion resistant coating. Patent 4,123,338 and Patent 4,522,844. A Google seach might turn up a few more applications. Mr.Z-man 21:03, 15 October 2007 (UTC)

Use in corrosion inhibition is discussed further in the section on industrial applications, where more detail is given on the suggestions which have been made and the experiments which have been done. So I have replaced the words "could eventually find use" by "has been suggested" in both the intro and the applications section. However the info in the applications section is not sourced, so I have also added a "citation needed" notice. Dirac66 (talk) 15:41, 22 May 2008 (UTC)

Stability of technetium isotopes

The below section was removed b/c it has been uncited for a year. It needs to be cited and cleaned-up before it is put back. --mav (talk) 00:51, 3 October 2008 (UTC)

Technetium and promethium are unusual light elements in that they have no stable isotopes. The reason for this is somewhat complicated.^[1]

Using the liquid drop model for atomic nuclei, one can derive a semiempirical formula for the binding energy of a nucleus. This formula predicts a "valley of beta stability" along which nuclides do not undergo beta decay. Nuclides that lie "up the walls" of the valley tend to decay by beta decay towards the center (by emitting an electron, emitting a positron, or capturing an electron).

For a fixed odd number of nucleons A, the graph of binding energies vs. atomic number (number of protons) is shaped like a parabola (U-shaped), with the most stable nuclide at the bottom. A single beta decay or electron captures then transforms one nuclide of mass A into the next or preceding one, if the product has a lower binding energy and the difference in energy is sufficient to drive the decay mode. When there is only one parabola, there can be only one stable isotope lying on that parabola. ^{[citation needed]}

For a fixed even number of nucleons A, the graph is jagged and is better visualized as two separate parabolas for even and odd atomic numbers, because isotopes with an even number of protons and an even number of neutrons are more stable than isotopes with an odd number of neutrons and an odd number of protons.

When there are two parabolas, that is, when the number of nucleons is even, it can happen (rarely) that there is a stable nucleus with an odd number of neutrons and an odd number of protons (although there are only 4 truly stable examples as opposed to very long-lived: the light nuclei: ²H, ⁶Li, ¹⁰B, ¹⁴N). However, if this happens, there can be no stable isotope with an even number of neutrons and an even number of protons.^{[citation needed]}

For technetium (Z=43), the valley of beta stability is centered at around 98 nucleons. However, for every number of nucleons from 95 to 102, there is already at least one stable nuclide of either molybdenum (Z=42) or ruthenium (Z=44).^{[citation needed]} For the isotopes with odd numbers of nucleons, this immediately rules out a stable isotope of technetium, since there can be only one stable nuclide with a fixed odd number of nucleons. For the isotopes with an even number of nucleons, since technetium has an odd number of protons, any isotope must also have an odd number of neutrons. In such a case, the presence of a stable nuclide having the same number of nucleons and an even number of protons rules out the possibility of a stable nucleus.^[2]

Technetium not synthetic

See http://en.wikipedia.org/wiki/Technetium_star . —Preceding unsigned comment added by 72.192.217.236 (talk) 19:57, 2 August 2009 (UTC)

It is synthetic in the sense it is not naturally encountered on Earth. Materialscientist (talk) 22:37, 2 August 2009 (UTC)

It is synthetic in that is was the first element to be discovered by artifical creation. It is found on earth in trace quantities in unusual circumstances. Jokem (talk) 21:27, 21 August 2009 (UTC)

Technetium

Why is it radioactive? Attinio (talk) 12:39, 21 September 2009 (UTC)

Isotopes_of_technetium#Stability_of_technetium_isotopes might help.--Stone (talk) 16:56, 21 September 2009 (UTC)

Organic complex

An "organic complex", which looks like a chemical molecule level extension of a periodic element unique to Technetium, as per the image on the page: File:Technetiumkomplex.png, seems like something that should have it's own article and page and be something highly important (a bridge or link of sorts between molecular drug chemistry and elemental particle physics? Is this unique to Technetium? What is this?) 4.242.174.81 (talk) 11:55, 15 October 2009 (UTC)

I added a reference and name: 3,3,9,9-Tetramethyl-4,8-diazaundecane-2,10-dione dioximato-oxotechnetium(V). As I understand, it is just an organic carrier of technetium for medical applications. Perhaps someone can elaborate on why this configuration is special. Materialscientist (talk) 01:24, 16 October 2009 (UTC)

Comments by Cryptic C62

Resolved comments

~~"In spite of the importance of understanding its toxicity in animals and humans, experimental evidence is scant." Huh?~~
(starting from the beginning) " It is a quasi-synthetic element with the atomic number 43 and is given the symbol Tc." What does "quasi-synthetic" mean? Synthetic element doesn't adequately explain it either.
Clarified. Materialscientist (talk) 08:09, 29 September 2009 (UTC)
"Technetium occurs in nature only in trace amounts as a spontaneous fission product of uranium and therefore is produced synthetically." This is definitely clearer, but it isn't entirely clear why technetium is produced synthetically. I assume that synthesis occurs so as to obtain more technetium than would be possible from harvesting it naturally; if so, the sentence should clarify this. --Cryptic C62 · Talk 17:45, 1 October 2009 (UTC)
Rewrote again. Materialscientist (talk) 07:44, 2 October 2009 (UTC)
"The pertechnetate ion (TcO−4) has been suggested as a strong anodic corrosion inhibitor for mild steel in closed cooling systems." I think the lead should focus on applications that are actually in use, not those that have been "suggested".
Agree and deleted from the lead - we can't use all potential applications there. Materialscientist (talk) 08:09, 29 September 2009 (UTC)
~~"Mendeleev noted a gap in his periodic table and called the undiscovered element ekamanganese (Em)." Why? What does "ekamanganese" mean?~~

Added: Mendeleev gave it the name ekamanganese, eka- from the Sanskrit words for one, because the predicted element was one place down from the known element manganese.--Stone (talk) 18:50, 1 October 2009 (UTC)

That is helpful, but I was referring to the fact as it appears in the lead. Ideally, the lead should not introduce terms that an unfamiliar reader won't understand. --Cryptic C62 · Talk 01:35, 4 October 2009 (UTC)

Ekamanganese should be treated just as a name. Its origin is explained further and it is by no means notable for the lead. Materialscientist (talk) 07:20, 4 October 2009 (UTC)

Okay. What about adding "provisional" to the sentence? This would help the reader understand the relationship between the names "ekamanganese" and "technetium". --Cryptic C62 · Talk 16:12, 5 October 2009 (UTC)
Added. Materialscientist (talk) 01:51, 6 October 2009 (UTC)

"In 1937 its isotope ⁹⁷Tc became the first predominantly artificial element to be produced, hence its name (from the Greek τεχνητός, meaning "artificial")." This sentence seems to contradict itself, as it refers to ⁹⁷Tc as both an isotope and an element. I suggest splitting this into two sentences for clarity: The first sentence would describe when ⁹⁷Tc was synthesized and by whom. The second sentence would mention that it was the first artificially-produced element and explain how it was named.
Elements occur as isotopes, so it's no contradition to say that a nuclide like Tc-97 is both. The word nuclide could be used instead of isotope, but isotope is being used in the correct sense, above, to refer to one of two-or-more nuclides of the same element. That said, rewriting wouldn't hurt.S B H arris 02:58, 2 October 2009 (UTC)
Agree that formulation could be better and tried to rephrase. Materialscientist (talk) 07:44, 2 October 2009 (UTC)
"No isotope of technetium has a half-life longer than 4.2 million years (⁹⁸Tc), so its detection in red giants in 1952 helped bolster the theory that stars can produce heavier elements." The first clause is a confusing way of stating that ⁹⁸Tc has the longest half-life at 4.2 million years. I do not understand the relationship between the first fact and the star theory.
The clause is not a way of restating something else-- it's meant to point out that Tc cannot last longer than a few multiples of its longest half-life, without some fresh source of production. Since the star is likely to be considerably older than 5-10 half-lives of Tc (20-40 million years) that means all the Tc would be undetectable there, if it weren't being freshly produced in the star.S B H arris 02:58, 2 October 2009 (UTC)
"On Earth, technetium occurs in trace but measurable quantities as a product of spontaneous fission in uranium ore or by neutron capture in molybdenum ores." This is the third instance in which this fact is discussed in the lead.

Okay, one of the others can go. It's okay to repeat things in the LEAD, which is a summary.S B H arris 02:58, 2 October 2009 (UTC)

Deleted one instance. Materialscientist (talk) 07:44, 2 October 2009 (UTC)

"For a number of years there was a gap in the periodic table between molybdenum (element 42) and ruthenium (element 44)." Is there a date range that could be added here to provide more context for the reader?
Tried that. One problem is that its hard to say when periodic table did appear. Materialscientist (talk) 07:20, 4 October 2009 (UTC)
"Dmitri Mendeleev predicted that this missing element, as part of other predictions, would occupy the empty place below manganese and therefore be chemically similar to manganese. Mendeleev gave it the name ekamanganese, eka- from the Sanskrit words for one, because the predicted element was one place down from the known element manganese." I feel that this chunk should be placed closer to the beginning of the paragraph, perhaps immediately after the first sentence.
Questionable, but I agree and moved it up. The point of separation is that Mendeleev's was prediction, but others tried to find the element experimentally. Thus I feel date sequence might be "broken" there. Materialscientist (talk) 07:20, 4 October 2009 (UTC)
I added a clause which I think helps to clarify the chronology. --Cryptic C62 · Talk 16:12, 5 October 2009 (UTC)
~~Why is "element 75" italicized throughout this section? None of the other elements are italicized.~~
Now several others are. Per MoS we shouldn't bold them, but it is useful to distinguish unconventional names. Minor point though. Materialscientist (talk) 07:20, 4 October 2009 (UTC)
Perhaps it wasn't clear what I was referring to. "element 75" is always italicized, but "element 42", "element 43", and "element 44" are not. --Cryptic C62 · Talk 16:12, 5 October 2009 (UTC)
Oh. Deitalized all "element xx" for uniformity - they are not really names (like ekamanganese) but rather "serial numbers" Materialscientist (talk) 01:51, 6 October 2009 (UTC)
~~"Contemporary experimenters could not replicate the discovery" What does "contemporary experiments" mean?~~
Changed to later for simplicity. Further alterations are welcome. Materialscientist (talk) 07:20, 4 October 2009 (UTC)
~~"However, the Noddack's experimental results" Should either be "However, Noddack's experimental results" or "However, the Noddack team's experimental results".~~
Changed to the latter version. I wasn't sure Noddack was the leader, but apparently he really was. Materialscientist (talk) 07:20, 4 October 2009 (UTC)
"In the summer of 1936 Segrè and his wife visited the United States" Is Segrè's wife relevant to the experiment? If so, this has not been made clear in this section. If not, I suggest removing her from this sentence.
Don't see her in publications, thus removed. Materialscientist (talk) 01:51, 6 October 2009 (UTC)
"This discovery was made by B.T. Kenna and P.K. Kuroda." An awkwardly terse sentence, especially since neither of the two discoverers is notable enough to have an article. Suggest either removing or incorporating their names into another sentence.
Agree. Removed. Materialscientist (talk) 23:35, 7 October 2009 (UTC)
"meaning its magnetic dipoles align with external magnetic fields even though technetium is not normally magnetic." The phrase "though technetium is not normally magnetic" is unclear. Does it mean that technetium does not produce its own magnetic field? Or that it only produces a field under non-normal conditions?
It was correct, but unclear. Changed to "..align with external magnetic fields, but will assume random orientations once the field is removed"
"Reaction of technetium with hydrogen produces anionic, negatively charged hydride [TcH9]2−." Anions are always negatively charged, are they not? This seems redundant and somewhat lacking in good grammar.
Yes, deleted anionic. Materialscientist (talk) 06:15, 14 October 2009 (UTC)
"Its oxides are TcO₂ and Tc₂O₇... Many technetium oxides are known." Unless I'm missing something, these two sentences seem to contradict each other.
The latter is incorrect and is deleted. Materialscientist (talk) 06:15, 14 October 2009 (UTC)
"It has characteristic spectral lines at 363 nm" What does "characteristic" mean here?
IMO, it is acceptable jargon. "Characteristic" means the dependence of intensity on wavelength has specific shape ("signature"). Materialscientist (talk) 06:15, 14 October 2009 (UTC)
Why does pertechnetic acid get its own subsection? Unless some explanation of its notability is given within the article, I suggest removing or merging it.
Merged into "oxides and hydrides". Oxides are basic compounds, and this acid is obtained just by reacting an oxide with water, thus it is a basic Tc compound and I wouldn't remove it. Materialscientist (talk) 06:15, 14 October 2009 (UTC)
"A few hydrogens (~2) can be replaced by sodium (Na+) or potassium (K+) ions." This seems totally irrelevant.
Why? That out of 9 of hydrogen atoms in an anion, ~2 can be replaced by Na+ or K+, producing another hydride, is a non-trivial fact. Materialscientist (talk) 06:15, 14 October 2009 (UTC)
Non-trivial to whom? This paragraph discusses this hydride and its variants in (as I see it) unnecessary detail without ever explaining the significance of these compounds. Are they useful? Do they have unusual properties? Also, what does "~2" mean? We're dealing with single-digit numbers, surely a precise range could be specified rather than leaving the reader to guess. --Cryptic C62 · Talk 19:39, 14 October 2009 (UTC)
Clarified more. We need to keep some tolerance in judging what is interesting to whom. For scientists (of any scope and level), hydrides are notable, and this one is remarkable in that it has the highest coordination number (9) of Tc. Materialscientist (talk) 00:32, 15 October 2009 (UTC)
"Every Tc atoms makes six bonds the remaining valence electrons can be saturated by one axial and two mu-bridging halogen atoms such as chlorine or bromine" This sentence seems to be missing some words/punctuation between "six bonds" and "the remaining". Also, is there something to which "mu-bridging" can be linked?
Added a word and a link. Materialscientist (talk) 05:59, 17 October 2009 (UTC)
"The bond length between Tc atoms, 303 pm, is larger than the distance between two atoms in metallic technetium." What is significant about this? I feel like this sentence asks more questions than it answers.
Added a bit. The difference means there is substantial charge transfer between the Tc and CO species. Two Tc atoms get "charged" and repel each other. Materialscientist (talk) 05:59, 17 October 2009 (UTC)
"where oxygen atom can be replaced by nitrogen" missing word before "oxygen".
Added. Materialscientist (talk) 05:59, 17 October 2009 (UTC)
"Two main technetium clusters are known, Tc6 and Tc8" The use of "main" implies that there are other non-main clusters known. If this is the case, I suggest specifying which ones. If this is not the case, I suggest removing "main".
Added a bit there. Materialscientist (talk) 05:59, 17 October 2009 (UTC)
Better, but now it isn't clear why these are considered the "main" clusters. Are they the most common? The most stable? Naturally-occurring? --Cryptic C62 · Talk 19:15, 18 October 2009 (UTC)
More stable. Changed. Materialscientist (talk) 04:24, 19 October 2009 (UTC)
"An example of a technetium complex with an organic ligand is shown in the right figure and is used in nuclear medicine." Article prose shouldn't refer to pictures or their locations. Not everyone will have access to the images or to this layout.
Removed "right". Mentioning that the figure is reflected in the text might help visually impaired, who read only (alt) texts in the figures. Materialscientist (talk) 05:59, 17 October 2009 (UTC)
I'm pretty sure there are mobile phone browsers which don't display images or their alt text, in which case mentioning a figure will simply confuse the user. --Cryptic C62 · Talk 19:15, 18 October 2009 (UTC)
Not a big deal. I think the note is useful and mobile reading is crippled in many other ways. Materialscientist (talk) 04:24, 19 October 2009 (UTC)
"Technetium is one of the two elements in the first 82" The meaning of this will be unclear to someone who is not already familiar with the periodic table. What is the significance of 82? What determines the order of the elements?
"(in fact, it is the lowest-numbered element that is exclusively radioactive)" This is arguably more important than the preceding statement. I suggest rewriting to avoid the use of parentheses and "in fact".
My rewrite might fix both. Materialscientist (talk) 04:24, 19 October 2009 (UTC)
"For isotopes lighter than the most stable isotope, 98Tc, the primary decay mode is electron capture, giving molybdenum. For the heavier isotopes, the primary mode is beta emission, giving ruthenium, with the exception that 100Tc can decay both by beta emission and electron capture" Redundant sentence. Most of this information is already presented in the first paragraph of this section. I suggest removing one of the two instances.
Certainly. Done. Materialscientist (talk) 00:07, 23 October 2009 (UTC)
"About 49,000 TBq (78 metric tons) of technetium is estimated to have been produced in nuclear reactors by 1994," Starting from when? A start date (even a rough estimate) would be helpful.
Added. It was clearly written in the source. Materialscientist (talk) 04:50, 26 October 2009 (UTC)
"By 1994, an estimated 160 TBq ..." This could also use a start date.
Added. Materialscientist (talk) 04:50, 26 October 2009 (UTC)
"and some seafood contains tiny but measurable quantities." I suspect that the source does not use "tiny", as it is a very unencyclopedic adjective. Is there another adjective or, even better, specific numbers that could be used instead? I suppose a specific number would also be useful in the lobster sentence that follows this one.
Added numbers, left "tiny" to avoid panic - otherwise people might stop eating Scottish sea products. Materialscientist (talk) 04:50, 26 October 2009 (UTC)
The Occurrence section uses several different methods for referring to isotopes: technetium-99, Mo-99, ⁹⁶Ru. These should be consistent.
1st and 3rd are both allowed on WP and in science and are mixed up. Not to say it is good, but 1st looks nicer in the beginning of the sentence, and 3rd is more scientific. I tried to remove 2nd - it is more of a slang (though it is used in scientific articles), but indeed, three versions are too many. This refers to all other articles too. Materialscientist (talk) 07:20, 31 October 2009 (UTC)
"long-term disposal of high-level radioactive waste" What does "high-level" refer to here? I suspect it means a high level of radioactivity, but it isn't entirely clear.
Yes, high radioactivity, but IMO, it was unnecessary there, and I just deleted that. Materialscientist (talk) 07:20, 31 October 2009 (UTC)
"many of the processes designed to remove fission products from medium-active" Do "high-level" and "medium-active" refer to the same scale? If so, I suggest making choosing either "level" xor "active".
Same solution as above. Materialscientist (talk) 07:20, 31 October 2009 (UTC)
"The anionic pertechnetate and iodide are less able to absorb onto the surfaces of minerals so they are likely to be more mobile" More mobile than what?
Corrected. No comparison intended, just to say they will get into solution and become mobile (simply put, will be washed away). Materialscientist (talk) 07:20, 31 October 2009 (UTC)
"Current disposal options favor burial in geologically stable rock." Not a very logically-written. If geological repositories are a disposal option, then what this sentence essentially says is "Current disposal options favor [a disposal option]." Suggest rewriting to avoid the use of "favor".
There are several disposal options, viable are two - continental and sea based. The second is currently snowed because of legal barriers. I added a word there. The phrasing is not optimal. Feel free to correct. Materialscientist (talk) 07:20, 31 October 2009 (UTC)
I think it would help to explain why this is the most favorable option. --Cryptic C62 · Talk 02:19, 1 November 2009 (UTC)
It is in wikilinked in the word "burial" - legal rather than technical issues, thus IMO, too boring for elements articles :-) Materialscientist (talk) 05:14, 1 November 2009 (UTC)
"By comparison plutonium, uranium, and caesium are much more able to bind to soil particles." This is a bad way to start a paragraph, because the sentence itself doesn't make any sense without having read the end of the previous paragraph. Suggest reorganizing the paragraphs or rewriting this sentence to more specifically discuss technetium.
Yes. Tweaked. Materialscientist (talk) 01:41, 3 November 2009 (UTC)
"The PUREX raffinate will contain a high concentration of technetium" Huh? I think some effort should be made to reword or explain the jargon in this sentence.
Rephrased. Materialscientist (talk) 00:55, 5 November 2009 (UTC)
"The vast majority of the 99mTc used in medical work "is produced by irradiating HEU [highly enrighed uranium] targets in a reactor, extracting 99Mo from the targets, and collecting the 99mTc that is produced when 99Mo decays."" Why does this sentence need a direct quote from the source?
Indeed. Removed. Materialscientist (talk) 00:55, 5 November 2009 (UTC)
Simply removing the quotation marks and spelling out HEU is insufficient: assuming the original sentence was correctly quoted from the source, the current sentence is plagiarism.
I've changed a couple of words and believe this should do: only a part of the original sentence was "quoted" (the quote was not exact actually). Materialscientist (talk) 06:32, 7 November 2009 (UTC)
"(meaning that about fifteen sixteenths of it decays to 99Tc in 24 hours)" I suggest using a percentage rather than a fraction, as it is more precise and less likely to cause confusion.
Done. Materialscientist (talk) 06:32, 7 November 2009 (UTC)
"Klaus Schwochau's book Technetium lists 31 radiopharmaceuticals" Unless this book is notable in its own right (which I suspect it is not), I suggest simply presenting the information without mentioning the book or its author. Perhaps something like "There are at least 31 commonly-used radiopharmaceuticals based on..."
Thanks. Done. Materialscientist (talk) 06:32, 7 November 2009 (UTC)
"Immunoscintigraphy incorporates 99mTc into a monoclonal antibody, an immune system protein," It may be unclear to readers whether "a monoclonal antibody" is one iteration of "an immune system protein" or if "a monoclonal antibody" and "an immune system protein" are members of a short list.
Corrected. Materialscientist (talk) 06:32, 7 November 2009 (UTC)
"higher concentrations indicate where the tumor is." Unless I'm misinterepreting how this technology works, I suggest replacing with either "a higher concentration indicates where the tumor is" or "higher concentrations indicate where the tumors are."
Corrected. Materialscientist (talk) 06:32, 7 November 2009 (UTC)
"These modified antibodies are sold by the German company Hoechst (now part of Sanofi-Aventis) under the name "Scintium"." Overly promotional and non-encyclopedic. Suggest removing.
Kept but trimmed: it is important in science to demonstrate that something is not just a lab reasearch, but is produced commercially. Hoechst is a huge company, mentioning such would rather mean recognition than company promotion. Materialscientist (talk) 06:32, 7 November 2009 (UTC)
Okay, that works for me. Follow-up query: Is Hoechst the only company that produces these antibodies? If so, the sentence is fine, but if not, I would suggest making it clearer.
Good point. Hoecht actually developed (and was selling) those antibodies, and this fact got into summary of Tc in academic sources on chemistry, thus I feel it is worth keeping. Don't feel like researching who is selling the product. Trade name could be kept or removed - no hard feeling here. Materialscientist (talk) 02:55, 10 November 2009 (UTC)
"Typical quantities of technetium administered for SPECT diagnostic tests range from 10 to 30 mCi for adults" I have two problems with this sentence. First, it introduces a technical term without explaining it. Second, it explains a very specific detail about an application without ever explaining what the application is.
Tweaked. Materialscientist (talk) 00:50, 13 November 2009 (UTC)
"The sulfur colloid of technetium-99m is scavenged by the spleen" Is "scavenge" the right word here? Spleen does not include any instances of "scavenge", nor could I find a relevant article to which "scavenged" could be linked.
Replaced by accumulated. "Scavenged" meant to accentuate the function of spleen - to accumulate some toxic substances. Materialscientist (talk) 00:50, 13 November 2009 (UTC)
"its quick decay into the far-less radioactive technetium-99 results in relatively less total radiation dose to the patient per unit of initial activity after administration." Relatively less? Relative to what?
To other radioisotopes. Tweaked. Materialscientist (talk) 00:50, 13 November 2009 (UTC)
"For these reasons, it is a NIST standard beta emitter, used for equipment calibration" Incorrect comma use introduces an ambiguity: "It is a NIST standard beta emitter used for equipment calibration" or possibly "It is a NIST standard beta emitter; it is used for (among other things) equipment calibration". In other words, does NIST specifically endorse it for equipment calibration? Or does NIST endorse it as a beta emitter and it happens to find use in equipment calibration?
Tweaked. There is no real problem here: NIST does not really endorse per se, it assesses and certifies, but. Because of NIST's high reputation, anything it certified automatically becomes a widely accepted standard. Materialscientist (talk) 00:53, 18 November 2009 (UTC)
"Under certain circumstances, a small concentration (55 ppm) of potassium pertechnetate(VII) in water protects steel from any corrosion." Confusing. What are these "certain circumstances"? The spatial relationship between the potassium pertechnetate, the steel, and the water is unclear; is the steel submerged in the water?
This was really obscure and is rewritten. Thanks. Materialscientist (talk) 00:53, 18 November 2009 (UTC)
"For example, no significant change in blood formula, body and organ weights, and food consumption could be detected for rats which ingested up to 15 µg of technetium-99 per gram of food for weeks." Unnatural ending. I suggest adding either hard data, such as "10 weeks", or a word like "several".
Yes, several weeks. No exact number because there were several experiments. Materialscientist (talk) 03:46, 20 November 2009 (UTC)

Unresolved issues

"It appears to have low chemical toxicity." Not a particularly strong sentence. I suggest removing this sentence and adding a toxicity paragraph/section sourced with an MSDS. I may try to do this later on. ~~In fact, much of the later information in Characteristics probably belongs in a Toxicity section.~~
Added a note with numbers. Materialscientist (talk) 09:56, 29 September 2009 (UTC)
"The chemical properties of this silvery gray, crystalline transition metal are intermediate between rhenium and manganese." A fairly useless sentence unless the reader is already familiar with rhenium and manganese.
Left, as I don't know how to improve that. There is an intrinsic relation between all elements of the periodic table. Materialscientist (talk) 08:09, 29 September 2009 (UTC)
Hmm, perhaps something about technetium's oxidation states? --Cryptic C62 · Talk 17:45, 1 October 2009 (UTC)
"three distinct decay periods (90, 80, and 50 days) that eventually turned out to be two isotopes, ⁹⁵Tc and ⁹⁷Tc," How is it that three decay periods become two isotopes? What happened to the third decay period?
Can't access the original ref. For a given isotope, there could be different modes of decay having different lifetimes, thus this is not a contradiction per se. Materialscientist (talk) 23:35, 7 October 2009 (UTC)
"It adopts a centrosymmetric corner-shared bi-tetrahedral structure, in which the terminal and bridging Tc-O bonds are 167 pm and 184 pm respectively and the O-Tc-O angle is 180°" Incredibly technical language, no links or explanations in sight, though my preference would be remove this entirely.
Yes. Simplified. Materialscientist (talk) 06:15, 14 October 2009 (UTC)
The language is still too technical for me to understand, and even if I were able to figure out what each term meant, I would wager that I still wouldn't see the significance of it. What about this heptoxide makes it notable enough to be discussed in this amount of detail? --Cryptic C62 · Talk 19:39, 14 October 2009 (UTC)
It is a compromise in terms of keeping information but trimming it to basic terms like bond length, bond angle, existence of a certain oxide, etc. IMO, this information could stay. Materialscientist (talk) 00:32, 15 October 2009 (UTC)
Stay on Wikipedia, yes. In this article, I think not. Perhaps in Technetium(VII) oxide, but as I see it, the information is utterly useless here.
I wouldn't argue over this one minor sentence. Materialscientist (talk) 05:59, 17 October 2009 (UTC)
"This is because of a quirk in nuclear structure" Is quirk the word that is used in the literature? It seems a tad unencyclopedic to me.
Tweaked. Materialscientist (talk) 04:24, 19 October 2009 (UTC)
More encyclopedic, but still vague. Is there any way to explain the "specificity" without using too much technical jargon?
Sorry, I'm not competent (better say not confident) enough to explain that. Materialscientist (talk) 00:07, 23 October 2009 (UTC)
"as it is a major product of the fission of uranium-235" This contradicts the first sentence of the next section: "only minute traces occur naturally in the Earth's crust as a spontaneous fission product of uranium" Is it minute or is it a major product?
The issue here is that total yields of fission are minute, even for "major products". Materialscientist (talk) 00:07, 23 October 2009 (UTC)
Remember that spontaneous fission is very rare in U-235, and natural neutron-induced fission (see natural nuclear fission reactor was only seen 2 billion years ago, and the Tc from that is long gone. It never happens today because U-235 enrichment is so low in modern U deposits. S B H arris 02:08, 23 October 2009 (UTC)
Then I think this should be more fully explained in the article. --Cryptic C62 · Talk 23:51, 25 October 2009 (UTC)
"Its decay, measured in becquerels per amount of spent fuel, is dominant at about 10⁴ to 10⁶ years after the creation of the nuclear waste" - I don't understand this sentence. How can 10⁴ years be a measurement of becquerels/fuel?
Becquerel, by definition, is one decay per second. Decay is quantified in two ways: by the number of decays/s and by the time its takes to reduce activity 1/e times. Materialscientist (talk) 04:50, 26 October 2009 (UTC)
I still don't understand. What does "dominant" mean in this context? --Cryptic C62 · Talk 16:48, 26 October 2009 (UTC)
Sbharris should know much better. I think there are many fuel decay processes going in parallel (that is many other elements); and that initially, Tc is insignificant, but after those 10⁴ years, the primary decay products are gone, and the Tc becomes dominant. Materialscientist (talk) 23:49, 26 October 2009 (UTC)
"During fuel reprocessing, it appears in the waste liquid" What is a waste liquid?
In that case, liquid left after processing the fuel, mostly water with all kind of dissolved impurities - a mix of everything. PS I've provided refs and thus uncommented some text. It was hidden and I have just noticed that. Sorry. Materialscientist (talk) 04:50, 26 October 2009 (UTC)
I think it should be made clearer exactly what is being reprocessed and what the waste liquid is. --Cryptic C62 · Talk 16:48, 26 October 2009 (UTC)
Ha, my practice is nobody wants to tell what is in their garbage, especially if its is radioactive and related to national security. :-) They probably have to specify max content of this and that, but not the composition. Materialscientist (talk) 23:49, 26 October 2009 (UTC)
Okay, but as the sentence is currently written, it just seems a bit mysterious. --Cryptic C62 · Talk 01:36, 31 October 2009 (UTC)

That's it for me! Good work as usual, mate. --Cryptic C62 · Talk 06:36, 20 November 2009 (UTC)

Stability

Here is an interesting link that explains something about why this element is radioactive but the ones around it are stable.

http://book.nc.chalmers.se/KAPITEL/CH03NY3.PDF

OK. I have a PhD in Astrophysics, but I really didnt understand the stability section! Could someone add some graphs or pictures showing the stability valleys, and also add the way it relates to nuclear spin, since I think this will make it make more sense... Fig (talk) 00:21, 23 November 2007 (UTC)

I think the current explanation is a non-explanation - while instability of technetium is a consequence of the stability of adjacent non-technetium isobars, there is no explanation of why those are stable. The "explanation" is more like a rephrasing of the question. --JWB (talk) 06:25, 23 November 2007 (UTC)

Link has moved servers. New link: http://jol.liljenzin.se/KAPITEL/CH03NY3.PDF --Djtrindle (talk) 13:45, 21 July 2010 (UTC)

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Decay chain missing

The article states that "traces occur naturally in the Earth's crust as a spontaneous fission product of uranium", but examination of the uranium decay chain does not show Tc. I would like to see at least a reference to the decay chain by which this Tc is produced naturally on earth. Eupedia 21:55, 3 May 2006 (UTC)

The phrase is 'hideous twist of fate'. There was some found in a uranium deposit in Africa, due to a freak natural 'refiner' which created the element. I have tried to find links to it and got this little bit.

http://www.accuracyingenesis.com/technet.html

If I'm reading the Genesis article correctly, it claims that the reason Tc came from breakdown of uranium was because there was so much more of it (uranium) in the deep past. If Tc is not listed as a breakdown product of U, then how would simply greater amounts account for this? It also says that Tc was found in the Colorado Molybdenum mine, which makes more sense. 82.93.133.130 09:22, 30 November 2006 (UTC)

The decay chain pertains to the usual methods of decay: alpha, beta, k-capture, or internal transition. Fission is not deterministic in the same way as the above four decay methods are, in that (1) it doesn't always result in the same outcome, and (2) the multiple products of a fission make the "chain" branched, which then isn't a chain. However, spontaneous fission can and does occur, especially when there is a supercritical assembly as has happened naturally in the past - in a location with an especially great amount, to answer your question. But spontaneous fission has a probability of happening even absent a supercritical assembly, so naturally occuring uranium from any source can be expected to contain traces of Tc. In fact Tc it is mentioned in the fission section of the linked decay chain article as I write this today ^[3] . (99mTc, specifically.) 192.91.173.34 (talk) 19:17, 1 February 2013 (UTC)beaker

Sound Speed - much too high and likely incorrect

The sound speed given (16,200 m/s) is faster than in beryllium (12,870) or diamond (12,000), which are among the stiffest and/or least dense materials that exist. It is also much faster than manganses (5150) which breaks the usual rule that sound speed decreases as atomic weight goes up, as much else as possible remaining the same. Therefore, the number is almost certainly incorrect. 192.91.173.34 (talk) 19:18, 1 February 2013 (UTC)beaker [edited to properly add signature after posting] — Preceding unsigned comment added by 192.31.106.35 (talk) 17:38, 1 February 2013 (UTC)

"Over three hundred twenty-seven half-lives have passed..."

"This is due to the fact that Technetium's half-life is only 4.2 million years. Over three hundred twenty-seven half-lives have passed since the formation on the Earth,"

This may be a foolish question -- I'm no chemist -- but if we take the age of the Earth at around 4.5 billion years, then haven't 4.5 billion/4.2 million = ~1071 half-lives passed since the formation of the Earth? If I'm correct, I'd suggest a wording change to "Over a thousand...." michael5000 (talk) 21:11, 14 August 2013 (UTC)

Looks wrong to me. A source would be better, but unless someone adds one I've corrected the figures from a recalculation; 1081 half-lives using 4.54 billion years (Age of the Earth), which gives 3.98942x10^-326. WP:CALC — Reatlas (talk) 09:01, 15 August 2013 (UTC)

infinitesimal?

How can a real-world quantity be infinitesimal? Shouldn't it just read "very small but measurable"? michael 02:09, 2 Jun 2005 (UTC)

I thought this too, so I changed it. Infinitesimals should be left for maths students and madmen to consider. Dmn / Դմն 08:18, 2 Jun 2005 (UTC)

How dare you call me a madman. (I'm a maths student.) Attinio (talk) 12:33, 21 September 2009 (UTC)

(since it was extremely unclear: tongue was firmly in cheek for that comment: now editing under new username) Double sharp (talk) 13:33, 8 February 2014 (UTC)

Hello Attinio (or whoever) I gather that my original comment on this (whose intended humour clearly misfired) offended you. But the fact remains that you have not been called a madman, though it is clear that you admit to being a maths student. You have committed a non-sequitur by assuming that the category 'madmen' includes 'all maths students' (though it might include some). I hesitate to say 'think about it' for fear of causing further offence. AJS77.96.59.93 (talk)

Scintium

Can you provide a source where Scintium by Hoechst is mentioned? If it is already included, a link to it should be added next to Scintium. I mean, I have not been able to find any useful mention of Scintium using Google neither on the web page of Hoechst. Thanks. --Eleassar777 11:43, 2 Jun 2005 (UTC)

The context shows a scintillation (physics) image. That might be the intended meaning. The image used to be formed on a phosphor screen, and would form a few speckles at a time over the period of the exposure, as a function of dose, distance, and aperature.
--Wikidity (talk) 01:46, 30 September 2014 (UTC)

Electron Configuration

Electron configuration on this page is different from Electron configuration, does anyone know which is correct? Beta34 14:47, 29 October 2007 (UTC)

Both have [Kr]5s2 4d5 but the difference is the order of the s and d shells. I've always seen the higher level shell listed first when doing electron configurations [C] 20:10 19may2013 EDT

Then you've always seen it the wrong way around. Electron configurations are written in the leaving order; 5s ionizes first and so it should be [Kr]4d⁵5s². Double sharp (talk) 04:37, 30 September 2014 (UTC)

Disintegration rate of 99-Tc

The halflife 0.2111 Ma would give 6.33e8 rather than 6.2e8 disintegrations per gram and second. — Preceding unsigned comment added by 150.227.15.253 (talk) 10:41, 11 December 2014 (UTC)

Discharge of technetium into the sea

"Discharge of technetium into the sea has resulted in some seafood containing minuscule quantities of this element. For example, European lobster and fish from west Cumbria contain about 1 Bq/kg of technetium". I find it hard to believe that such tiny radioactivity is detectable. A Becquerel is one decay per second per Kg so for a 1Kg lobster this is one decay per second. I will try and find some references to do with this. Mtpaley (talk) 22:57, 3 May 2016 (UTC)

Electron configuration

Greenwood and Earnshaw are inconsistent on this. In the front cover they have [Kr]4d⁵5s², while in the chapter on Mn, Tc, and Re they have [Kr]4d⁶5s¹. Both have been quoted quite recently (first; second). I must confess that the second would be more amusing, if only for how it blows the "half-filled subshells are more stable" justification out of the water, but it would be nice to know which is the ground state, and how close they are in energy. Double sharp (talk) 09:11, 9 July 2016 (UTC)

See Tc I here: [5] Burzuchius (talk) 10:00, 9 July 2016 (UTC)

OK, so [Kr]4d⁵5s² is the ground state. I suppose [Kr]4d⁶5s¹ must be low enough to have some importance in chemistry. Double sharp (talk) 11:23, 9 July 2016 (UTC)

Pronunciation

The article claims the element is "pronounced tek-nee-s(h)ee-um". This seems to be a hyper-Americanism ("hyper" in the sense that I, as an American, would not use it, but would prefer the three-syllable pronunciation, in spite of perceiving the latter as more "British-sounding"). OTOH I don't have a lot of call to use the word in my daily conversation, so my guesses here could be off. Comments? --Trovatore 15:40, 28 March 2006 (UTC)

I worked in a small hospital in West Michigan. We said "tek-NEE-see-um" as rhymes with "magnesium." Nobody said Tek-nee-shum, although a new guy who joined just before I left said "tek-NEE-zsi-um" (the voiced "s") . Hope this helps. Hope a Brit adds on. 82.93.133.130 16:57, 28 November 2006 (UTC)

In British-English it can be pronounced Tek-neh-tee-um. —Preceding unsigned comment added by Tsibuki (talk • contribs) 00:08, 20 March 2008 (UTC)

I say "tek-net-ium" too. (If only EVula got here and said this was correct.) Attinio (talk) 12:35, 21 September 2009 (UTC)

One more vore for "tek-net-ium" (stress on the middle part); I'm from the northeastern US. It wouldn't have occurred to me to change the "ti" sound to a "shi". Mark Yaima (talk) 18:18, 28 March 2011 (UTC)

From Virginia, I say 'tek-ne-shum' (similar to technician), but have decided that since original pronunciations from around the US vary, we should try to go to the source material by the discoverer. I never did, but from this article, we should try to pronounce it as an Italian speaking Greek(:-), and not be embarrassed if our co-workers glare at us.--Wikidity (talk) 02:09, 30 September 2014 (UTC)

The very suffix "ium" has TWO syllables in it, so all of you who have indicated it as one are in the wrong. That's a sloppy mistake as can be seen from the three-syllable names barium, cadmium, calcium, cesium, chromium, curium, fermium, francium, gallium, hafnium, helium, holmium, kalium, lithium, natrium, osmium, radium, sodium, strontium, and thorium.47.215.188.197 (talk) 11:03, 8 February 2017 (UTC)

I wonder what you're trying to prove by using "kalium" and "natrium"? Yes, "-ium" is supposed to be two syllables, but in fast speech it can get slurred into one pretty easily. Double sharp (talk) 12:18, 8 February 2017 (UTC)

History before Periodic Table

I have a question regarding the following information in the article:

For a number of years there was a gap in the periodic table between molybdenum (element 42) and ruthenium (element 44). Many early researchers were eager to be the first to discover and name the missing element; its location in the table suggested that it should be easier to find than other undiscovered elements. It was first thought to have been found in platinum ores in 1828. It was given the name polinium but it turned out to be impure iridium. Then in 1846 the element ilmenium was claimed to have been discovered but was determined to be impure niobium. This mistake was repeated in 1847 with the 'discovery' of pelopium.

Now my question is this: How could all these people have been looking for an element in the gap of a periodic table that had not yet been proposed? There were of course precursors of Mendelejev like Meyer, Newman, or Béguyer but to my knowledge even they published their work in the 1860s. So what exactly did the people who "found" polinium, ilmenium oder pelopium think they had found? Any answer would be appreciated --Aglarech-en 14:22, 24 Jun 2005 (UTC)

Change 1828 for 1928 etc and you have a reasonable chronology of Irene Noddack's claims to have discovered element 43. The proposed names don't ring a bell though. I will try and check it out, even though I am supposed to be on WikiVacation... Physchim62 8 July 2005 10:27 (UTC)

I thought that Ilmenium was the prediscovery name for element 61 (Promethium)

NOTE: a gap in the periodic table between molybdenum (element 42) and ruthenium (element 44). Back in those years (in 1800-1912) the concept of "atomic number" was completely unknown, and it is ridiculous to mention it right here. Only atomic masses were known back then, and those are not integers or reliable measurements from this point-of-view: even Mendeleev had to reverse some pairs of elements from their order in atomic mass, and this was part of his genius to do so. Also, if you "perceived" a gap in the Periodic Table, there was no way to decide if there were 0, 1, 2, 3, 4,... elements in that gap. When it came to the whole set of lanthanide rare earths, some chemists estimated that there could be as many as 25 of them, but this was rather a wild guess. During 1913-15, Henry Gwyn-Jeffreys Moseley developed the concept of "atomic number" from data that he collected by X-ray crystallography. Moseley was able to show that there was exactly ONE missing element between molybdenum and ruthenium, and that there was also ONE missing rare earth, and that one was promethium, which he deduced had atomic number 61. He also deduced that there were missing elements at his NEW atomic numbers 72 hafnium, 75 rhenium, both stable elements, and the very radioactive ones of francium and astatine. Francium was one was the one where mistaken results were named illinium, and astatine was the one where mistaken results were named alabamine for the Alabama Polytechnic Institute (API), renamed Auburn University since 1960. At the time of Moseley (killed in Gallipoli in 1915), the heavier radioactive metals were known, including uranium, thorium, radium, and polonium, and some of these could be tested in his X-ray tubes. Radon could not be tested since it is an inert gas, and some of the others (unknown ones) are extremely radioactive, poisonous, and corrosive even if you could get some. 47.215.188.197 (talk) 10:20, 8 February 2017 (UTC)

Ilmenium is not to be confused with illinium, named for the University of Illinois.10:46, 8 February 2017 (UTC)

I don't see how Rn's inertness stops one from testing it; this has nothing to do with chemistry, and Moseley had no problem testing the stable noble gases. Double sharp (talk) 10:58, 7 June 2017 (UTC)

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Pertechnetate or pertechnate?

I corrected what I thought was a typo by replacing pertechnate with pertechnetate only to see that pertechnate is used throughout the article. I work with the stuff and we call the O4- ion "pertechnetate". Is this a UK thing, or are both spellings correct? A quick search with google show both spellings on a range of web pages. Perhaps a chemist can enlighten us? --AjAldous 12:46, 2 Jun 2005 (UTC)

Google strongly prefers "pertechnetate", however, and since the root of the thing is "technet-", it's also arguably correct. "Pertechnate" seems to be a variant by omitting a repetitive syllable; it could be acceptable, but there's no reason to assume it is. I've taken the liberty of changing it to "pertechnetate" throughout—the burden is on the lesser-used word to prove its validity. JRM · Talk 15:36, 2005 Jun 8 (UTC)

Like phosphate. It's not "Phosphorate", right? Porygon-Z 20:52, 27 November 2018 (UTC)

No, but it makes more sense to look at the roots for elements that end in -ium like technetium. And indeed in these cases the full form is used: vanadium, vanadate; chromium, chromate; rhenium, rhenate. As such it makes sense that technetium oxyanions be technetates. Elements that don't end in -ium may differ: platinum, platinate; but molybdenum, molybdate. Double sharp (talk) 02:27, 28 November 2018 (UTC)

IUPAC says it's technetate. Burzuchius (talk) 08:49, 29 November 2018 (UTC)

....Right but where can i get technetium?Porygon-Z 19:06, 30 November 2018 (UTC) — Preceding unsigned comment added by Porygon-Z474 (talk • contribs)

Bq ->g

How many grams of metallic technetium correspond to 1 TBq? Let's see:

1 TBq is $10^{12}$ decays per second. The number of atoms remaining in a sample that starts with N atoms after t seconds is $Ne^{{\frac {t}{3.1556\times 10^{7}\times 211100}}\ln 2}=Ne^{-1.04\times 10^{-13}t}$ , so the number of decays per second is initially $-1.0405\times 10^{-13}N$ . So 1 TBq is about $9.611\times 10^{24}$ atoms, which is about $9.611\times 10^{24}\times 99/(6.022\times 10^{23})=1580$ grams. Equivalently, 0.6329 GBq/g. The most unreliable number here is the isotopic mass.

Ok, going to fill in amounts in the article. --Andrew 07:39, Apr 24, 2005 (UTC)

Oops, corrected arithmetic error. Going to fix the article.

The number of becquerels/gram is a handy number too; this is roughly what's in the article. --Andrew 11:12, Apr 24, 2005 (UTC)

I see your unreliable number and raise you another order of magnitude. 98.9062546(21) You also still missed some numbers, which doesn't seem to have affected the math though. I know little about the conventions regarding radioactivity. Seeing an amount of substance given as 'decays per second' feels so strange. Femto 16:33, 24 Apr 2005 (UTC)

Contradiction in Article?

The blurb at the frontpage says that technetium is a gamma-ray free source of beta rays, as it also says in the industrial applications subsection. However under medical applications it clearly says that it does not produce beta radiation, but instead gamma-radiation.

So who's right?

-- Rune Welsh ταλκ 00:15, Jun 2, 2005 (UTC)

This may shock you but elements like technetium come in different kinds, called isotopes. These isotopes behave very differently on the atomic scale while reacting (almost) identical chemically. See the new updated table for the various common isotopes of technetium, some are beta and gamma, some are only gamma and some are only beta. So in a sense and probably indicated by the article both are right.--metta, The Sunborn 03:06, 2 Jun 2005 (UTC)

They are both right - the isotope Tc99 is the beta emitter, the isotope Tc99m is the pure gamma emitter. --AjAldous 12:32, 2 Jun 2005 (UTC)

problems

Is it really a superconductor below 11K? If so, what is the "critical temperature" at 7.77K? It doesn't seem to be a critical point as linked. --Andrew 02:22, Apr 23, 2005 (UTC)

No, there was a long-published error; the transition temp. is 7.75K. It's "excellent" because it has a high field penetration coefficient (whatever that is) and it was considered one of the best choices in 1968. Now, I doubt anyone would contemplate using it for its superconductivity. --Andrew 05:55, Apr 23, 2005 (UTC)

>Its characteristic absorption maxima are at 247 and 285 mµ.

Are these absorption wavelengths? For the metal in gas phase, I guess. And is the unit supposed to be microns (µm)? That's almost a millimeter, way way into the infrared, almost to microwave. --Andrew 02:22, Apr 23, 2005 (UTC)

That would likely be "millimicrons", equivalent to SI nanometers. The use of this unit also means that the data hasn't seen any serious update since 1960 or so. Careful here. Femto 13:37, 23 Apr 2005 (UTC)

Deleted this and put in spectral lines from CRC handbook. The numbers are totally different, which is not reassuring. --Andrew 16:06, Apr 26, 2005 (UTC)

>A diphosphate ion with Tc-99m adheres to heart muscle, making it useful to gauge damage done after a heart attack.

The comment has pyrophosphate in question marks. Is it actually pyrophosphate? --Andrew 02:22, Apr 23, 2005 (UTC)

Yes. --Andrew 06:21, Apr 23, 2005 (UTC)

On what timescale is Tc eliminated from the body? Presumably not hours, but maybe days or weeks? --Andrew 02:22, Apr 23, 2005 (UTC)

"Within a few days." --Andrew 06:21, Apr 23, 2005 (UTC)

Most of the "other uses" also appear to be medical; why are they not in with the other medical uses? --Andrew 02:22, Apr 23, 2005 (UTC)

>The group bombarded columbite with a beam of electrons and deduced element 43 was present by detecting faint x-rays.

Er, you usually get X-rays when you zap something with X-rays. Presumably it was something about the X-rays that suggested Tc was present. What? --Andrew 02:22, Apr 23, 2005 (UTC)

Solved. --Andrew 10:33, Apr 24, 2005 (UTC)

>The meta stable isotope Tc-99m is produced as a byproduct from the fission of uranium in nuclear reactors and it is prepared by chemically separating it from the reactor's radioactive waste. Specifically, the radioactive isotope molybdenum-99 (half life, 67 hours) decays to Tc-99m, which in turn can be easily separated from its parent isotope.

I don't think they can separate Tc-99m from Tc-99, and it is surely infeasible to do this in a couple of hours, so I would think they'd extract the molybdenum from the waste, and then the technetium from the magnesium. --Andrew 02:22, Apr 23, 2005 (UTC)

Yes, this is what they do; we have a picture. --Andrew 10:33, Apr 24, 2005 (UTC)

>The primary decay mode before the most stable isotope, Tc-98, is electron capture and the primary mode after is beta emission with one instance of election capture during the first mode of the two mode decay of Tc-100.

By "before" and "after" I suppose you mean "smaller mass" and "greater mass"? This is also pretty unclear. I suppose everything above (and including?) Tc-98 decays primarily by beta emission, except for Tc-100. Tc-100, I gather, decays (primarily?) in two ways (equally probable?), one of which is electron capture (is the other beta emission?). --Andrew 02:22, Apr 23, 2005 (UTC)

Yeah. Solved with reference to the CRC handbook. --Andrew 15:53, Apr 26, 2005 (UTC)

Under "Precautions" it would be good to indicate that it is rapidly eliminated from the body, once numbers (or at least a concrete reference) are found for that fact (used elsewhere). --Andrew 02:22, Apr 23, 2005 (UTC)

~~What's with the duplicate 'first ionization energy/potential' entries? Femto 13:37, 23 Apr 2005 (UTC)~~

~~I don't see them anymore, is this fixed? --Andrew 15:53, Apr 26, 2005 (UTC)~~

Oh my - so many fast improvements since my expansion. Great job! I'll take a look at my sources soon to help fix the still-remaining outstanding items. Once that it is done, I'll submit this article to FAC as a truly collaborative work. --mav 17:06, 25 Apr 2005 (UTC)

Done. --mav 01:59, 27 Apr 2005 (UTC)

>> lead section: The chemical properties of this silvery gray, radioactive, crystalline transition metal are intermediate between rhenium and manganese and it is very rarely found in nature.

This reads "the metal...is (very rarely) found in nature"—which doesn't do it justice. Femto

>> every gram of the rare isotope uranium-235 burned in nuclear reactors yields 27 mg of Tc-99

U-235 isn't all that "rare", especially since "very rare" is used earlier to describe the abundance of Tc, and the difference appears to be greater than a simple 'very'. Also, we should avoid the word "burned" here, which may be understood as ordinary combustion by many people. Femto 17:48, 27 Apr 2005 (UTC)

^ http://book.nc.chalmers.se/KAPITEL/CH03NY3.PDF
^ RADIOCHEMISTRY and NUCLEAR CHEMISTRY
^ http://en.wikipedia.org/wiki/Decay_chain#Beta_decay_chains_in_uranium_.26_plutonium_fission_products

[1] ttp://book.nc.chalmers.se/KAPITEL/CH03NY3.PDF

[2] RADIOCHEMISTRY and NUCLEAR CHEMISTRY

[3] ttp://en.wikipedia.org/wiki/Decay_chain#Beta_decay_chains_in_uranium_.26_plutonium_fission_products

[1]

[2]

[3]