Talk:Technetium

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May 3, 2005	Featured article candidate	Promoted
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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).

[edit] 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.

[edit] 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)

[edit] 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)

[edit] Bq ->g

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

1 TBq is $1012$ 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)

[edit] 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)

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

^{[edit] 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)}

^{[edit] 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)}

^{[edit] 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)}

^{[edit] 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)}

^{[edit] 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)}

^{[edit] tungsten and bismuth}

^{I removed some edit that claimed tungsten and bismuth were unstable elements. While bismuth is technically unstable it is not special because it is the boundary of stablity. Tungsten on the other hand is quite stable. environmentalchemistry.com --metta, The Sunborn 16:52, 2 Jun 2005 (UTC)}

^{This is technically not true about Tungsten http://en.wikipedia.org/wiki/Tungsten Naturally occurring tungsten consists of five isotopes whose half-lives are so long that they can be considered stable.}

^{[edit] 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 Ilmenium was the pre-discovery name for element 61 (Promethium)}

^{[edit] 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}

^{[edit] 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)}

^{[edit] 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)}

^{[edit] 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)}

^{[edit] 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)}

^{[edit] 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)}

^{[edit] 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.

[edit] 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?

[edit] 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)

[edit] 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)

[edit] Refs

R. C. L. Mooney (1948). "Crystal structure of element 43". Acta Cryst. 1: 161-162. DOI:10.1107/S0365110X48000466.
Schwochau K. (1948). "The Present Status of Technetium Chemistry". Radichimica Acta 21 (1-3): 139-152.

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