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The following is an archived discussion of a featured article nomination. Please do not modify it. Subsequent comments should be made on the article's talk page or in Wikipedia talk:Featured article candidates. No further edits should be made to this page.

The article was not promoted by SandyGeorgia 21:13, 27 February 2010 [1].

Caesium

[edit]

Caesium (edit | talk | history | protect | delete | links | watch | logs | views)

Nominator(s): Nergaal (talk) 06:06, 14 February 2010 (UTC); Stone[reply]
Toolbox

There hasn't been a chemical element up for FAC in quite some time. I believe this article is complete, well organized and well referenced. There should be only a few touchups remaining which will hopefully be caught in this FAC. Nergaal (talk) 06:06, 14 February 2010 (UTC)[reply]

Note: This is a WikiCup nomination. To the nominator: if you do not intend to submit this article at the WikiCup, feel free to remove this notice. Ucucha 12:57, 14 February 2010 (UTC)[reply]
Alt text issues fixed. The 055 Caesium.svg alt text is a tricky issue to fix as the template used there is very complex and automatically adds that text depending on the element page present. Nergaal (talk) 21:21, 14 February 2010 (UTC)[reply]
Thanks, much better, except that File:Cs-137-decay.svg still lacks alt text and there are a few instances of WP:ALT #Phrases to avoid, namely "The diagram shows", "The image shows", and "An image of". As for the alt text of File:Electron shell 055 Caesium.svg, on second thought, since that image is completely illegible how about if we just remove it? I can easily modify the template to do that. Eubulides (talk) 21:40, 14 February 2010 (UTC)[reply]
Fixed all instances of "image of". The decay image actually has alt text, and you can see it in the actual article (not the alt checker). Feel free to make it work, as there seems to be some issue with how alt syntax works in this instance. The electron shell is standard for all of the chemical element articles. In most instances, the image is large enough for clear readability, but in the late element chases this is not achieved very well. I see no point in removing it. Nergaal (talk) 23:15, 14 February 2010 (UTC)[reply]
Standardization is not a good idea when it harms the article. At this size, the electron shell image is virtually useless, and dilutes the value of other more useful images. Ucucha 23:20, 14 February 2010 (UTC)[reply]
The point I was making is that the infobox uses a complex set of commands which automatically produce such entries like this one. The template used to be wider such this type of images were fine. With a thinner template, this is somewhat of an issue for later elements. Nevertheless, this is not a quickfix and feel free to raise the issue at wp:Elem or even try to fix it yourself. I think this is well beyond the point of this FAC, and I would much rather focus on the article improvement rather that bog this down with nitpicking. Ner"In the past FAC was all about making the references look pretty; now it became cool to slow down reviews with hidden options such as alt text that way less than 5% of the users ever use"gaal
I checked other articles, and the electron shell image was unreadable everywhere, so I removed it from the template (please see Template talk:Elementbox #Electron shell image unreadable and inaccessible for details). The decay image does not have alt text: its wiki markup is merely [[File:Cs-137-decay.svg|thumb|right|250px|Decay scheme of caesium-137]] and there's no alt text there; could you please add it? It's true that most readers don't need alt text, but the people who need it really need it. Eubulides (talk) 06:34, 15 February 2010 (UTC)[reply]
I did actually add the text, but some user overwrote my edit. It should be back in now. Ner"Wikipedia also needs more users who contribute because they enjoy it, not more who get exhausted by more and more obscure MOS-ish rules"gaal (talk) 08:39, 15 February 2010 (UTC)[reply]
That fixes all the alt text problems I found. Writing alt text can be both relaxing and entertaining, but (like other aspects of Wikipedia article writing) it's not for everybody. Thanks again for writing it. Eubulides (talk) 08:58, 15 February 2010 (UTC)[reply]
fixed Nergaal (talk) 16:21, 14 February 2010 (UTC)[reply]
OK, external links fine now. Ucucha 23:20, 14 February 2010 (UTC)[reply]

Otherwise, images appear to comply with policy. –Juliancolton | Talk 16:05, 14 February 2010 (UTC)[reply]

  • Comments -
  • Need to italicise the Handbook of Chemistry and Physics in the infobox ref
  • Current ref 34 (Cesium Atoms..) lacks a publisher
  • Newspaper titles in the refs should be in italics (I noted current ref 40 and 76 but there may be others)
Otherwise, sources look okay, links checked out with the link checker tool. Ealdgyth - Talk 16:24, 14 February 2010 (UTC)[reply]
I've fixed the italicizations for both the infobox reference and the newspaper titles. The latter was a result of some templates using the publisher parameter when they should have been using the newspaper parameter. I have not done anything with ref 34. {{Nihiltres|talk|edits|⚡}} 17:38, 14 February 2010 (UTC)[reply]
Fixed ref 34. Nergaal (talk) 19:41, 14 February 2010 (UTC)[reply]
  • Strong oppose. All sorts of problems. Here's my selection from the first quarter of the article: And I've now looked elsewhere. There appear to be significant issues with close paraphrasing and unreliable sourcing of facts. I don't think the editing work being done by nergaal can address my concerns. Please understand that I am not accusing nergaal of having introduced the plagiarism / close paraphrasing etc, but the article has problems that will need significant examination. My main concern is that this article represents plagiarism of the USGS source to an unacceptable degree. See below for some examples. hamiltonstone (talk) 03:47, 22 February 2010 (UTC)[reply]
  • No citation for "The radioactive element francium may also have lower melting point".
  • "At temperatures below 650 °C, it alloys with cobalt, iron, molybdenum, nickel, platinum, tantalum or tungsten.[3] On the other hand,..." Why is the phrase "on the other hand" used here? A dichotomy of some sort does not appear to be what is being described.
  • "reaction with water is explosive even at temperatures as low as −116 °C." That is not what the sources says. It indicates explosive reaction with water, and re-action (not explosive) with ice (not water) as low as -116 degrees. This makes me concerned whether other errors have crept in.
  • An article which provides a wikilink for "liquid" but not for "borosilicate glass" is in serious need of its links being reviewed.
  • Have another look. A glance showed "Mercury (element)" linked twice, "alkali metal" linked three times and "metal" linked, which seemed to me excessive in this article. And all that was just in the first couple of sections. hamiltonstone (talk) 10:58, 19 February 2010 (UTC)[reply]
  • I'll let other editors comment on whether this represents plagiarism or excessively close paraphrasing of the source, but it fails in my view:
  • Source (quoting parts of 2 separate paras): "Because of this reactivity, cesium is classed as a hazardous material and must be stored and transported in isolation from possible reactants... is stored and shipped in dry mineral oil or in other dry saturated hydrocarbons or in an inert atmosphere or vacuum in sealed borosilicate glass ampoules. In quantities of more than about 100 grams (g), cesium is shipped in hermetically sealed stainless steel containers. When glass ampoules are used, they are shipped wrapped in foil and packed in an inert cushioning material, such as vermiculite, each in a metal can."
  • WP Article: "Because of its high reactivity, caesium metal is classified as a hazardous material and must be stored and transported in isolation from possible reactants. It is stored and shipped in dry mineral oil or in other dry saturated hydrocarbons, or in an inert atmosphere (such as argon or nitrogen) or vacuum, in sealed borosilicate glass ampoules which are shipped wrapped in foil and packed in an inert cushioning material, such as vermiculite, each in a metal can. In quantities above 100 grams, caesium is shipped in hermetically sealed stainless steel containers".
  • I have rephrased it; now it says: Due to its high reactivity, the metal is classified as a hazardous material. Storing and shipping is usually done in dry mineral oil, or in other dry saturated hydrocarbons, or in sealed borosilicate glass ampoules under an inert atmosphere (such as argon or nitrogen) or vacuum, and packed in an inert cushioning material such as vermiculite in a metal can. Hermetically sealed stainless steel containers are used for quantities above 100 grams Nergaal (talk) 08:36, 15 February 2010 (UTC)[reply]
  • No source for the following: "Some small differences arise from the fact that Cs is heavier and more electropositive than other (non-radioactive) alkali metals. Caesium is the most electropositive stable chemical element, and of all the known elements, only francium may be more electropositive (as francium is highly radioactive, it cannot be isolated in observable quantities yet). Relativistic effects can lower the reactivity and raise the electronegativity of francium, as suggested by its value of the first ionization energy" Happy as long as the tag you've added stays until a source is found. hamiltonstone (talk) 01:21, 17 February 2010 (UTC)[reply]
  • The para beginning "Because of its large ionic radius, caesium is one of the incompatible elements" has just one footnote at the very end of a lot of material. I scanned the abstract and did a few searches of the journal article in question. I couldn't find any of the WP article facts in the source.
  • The section beginning "Acid digestion is the principal commercial method used and usually employs..." again cites the USGS paper but again looks to me like unacceptable close paraphrasing or plagiarism. Example:
  • Source: "The alum is roasted with 4 percent carbon and then leached to yield a Cs2SO4 solution; the sulfate may then be converted to CsCl."
  • WP Article: "The alum is roasted with 4% carbon and then leached to yield a Cs2SO4 solution, which may then be converted to CsCl."
Tried again. Nergaal (talk) 21:08, 18 February 2010 (UTC)[reply]
I haven't read further. hamiltonstone (talk) 23:42, 14 February 2010 (UTC)[reply]
I went and fixed a lot of the issues. I added several fact tags where I thought the text still needs referencing and I will find some tomorrow. Feel free to add fact tags directly into the text where you feel it is necessary. I also went through the parts of the text which may have relied too much on paraphrasing the USGS report, and I've tried to cleanup them. Let me know if there are still such instances left. Nergaal (talk) 08:36, 15 February 2010 (UTC)[reply]
Thanks for working hard on the article. I remain concerned at the level of paraphrasing of, and reliance on, the USGS source. Other fixes look sound. hamiltonstone (talk) 01:21, 17 February 2010 (UTC)[reply]
The US Geological Survey report is supposed to be a great tool for the occurrence and for the production sections, and I think should be considered as one of the most reliable sources possible here. Asides from that and the part of the uses, I think it is only rarely used in other sections. As this not-that-important element didn't receive much attention in the literature, it couldn't find other reviews on the its uses. Do you have any suggestions about finding other respectable reviews? Nergaal (talk) 03:21, 17 February 2010 (UTC)[reply]
I have tried to reduce the amount of dependency on the USGS source. While there are still a through z occurances, it is probably about 1/3 less than before. Is it ok now? Nergaal (talk) 21:02, 18 February 2010 (UTC)[reply]

Break, and resuming my oppose (as it were)
I have concerns about this article - i am not saying they are with the nominator. I've started to look more closely at selected spots.

  • In the first sentence under "compounds", is this: "Caesium hydroxide (CsOH) is hygroscopic and a very strong base, and will rapidly etch the surface of glass or quartz". The citation is what i would consider a fairly obscure patent application. i would not rate it as the best of sources at FAC. But, leaving that aside, I was unable to locate this fact on two read-throughs.
    I rewrote the sentence in question and replaced the ref with two others, one for the basic characteristics and one for the etching. --Cryptic C62 · Talk 18:26, 24 February 2010 (UTC)[reply]
  • Next, take the second para under "compounds", which currently begins "Caesium chloride is an important source..." There is only one footnote, at the end of the para. The combination of a lack of context here, and an odd turn of phrase ("The chloride atoms lie upon the lattice points...") makes me suspicious that this has been inappropriately plagiarised or close paraphrased from the source (or from elsewhere). I would be grateful if someone with access to this book would take a look.
  • Here is one of the most telltale examples of a problem in this article. Under "History", we find this in the WP article:
"It found no significant application until it was added into radio vacuum tubes in the 1920s as a getter, a scavenger of the trace amounts of oxygen remaining in the tube after manufacture, and as a coating on the heated cathode to increase the amount of electric current that could flow through the tube. Caesium became recognized as a functional, high-performance industrial metal in electronics in the 1950s." It is footnoted to a 1957 paper.
Meanwhile, we find this in the USGS source:
"The element found no significant application until it was used in radio vacuum tubes in the 1920s as a getter, which is a scavenger of the trace amounts of oxygen remaining in the tube after manufacture, and as a coating on the heated cathode to increase ... the amount of electric current that could flow through the tube. Cesium became recognized as a functional, high-performance industrial metal in the field of electronics in the 1950s (Strod, 1957)." The quote, including a source not actually viewed by the reviewer, has been plagiarised from the USGS paper.
I have rewritten this paragraph to avoid close paraphrasing. --Cryptic C62 · Talk 18:00, 25 February 2010 (UTC)[reply]
  • Also in the history section, which begins "In 1860, Robert Bunsen and Gustav Kirchhoff discovered caesium in mineral water from Dürkheim, Germany". There is no cite at the end of this particular sentence. But, guess what: here's a sentence from the USGS report: "Cesium, which was the first element discovered by using emission spectroscopy, was detected in water from mineral springs in Germany by Robert Bunsen and Gustav Kirchhoff in 1860".
    • We can substitute it by the sentence from the article written in mid 2002 so two years before the USGS report and one year before the EPA report: This would that be:Cesium (L. caesius meaning sky blue) was spectroscopically discovered by Robert Bunsen and Gustav Kirchhoff in 1860 in mineral water from Durkheim., but for me this sentnce will always being very similar, because inthis sentence you cannot say that In 1912 Wilhelm Müller found the caesium in the mineral pollucite bay mass spectroscopy. --Stone (talk) 21:15, 24 February 2010 (UTC)[reply]
  • Under "petroleum exploration" we have this: "The high density of the caesium formate brine (up to 2.3 g/cm3, or 19.2 pounds per gallon), coupled with the relatively benign nature of most caesium compounds, reduces the requirement for toxic high-density suspended solids in the drilling fluid—a significant technological, engineering and environmental advantage. Unlike the components of many other heavy liquids, caesium has minimal radioactivity because it is almost entirely composed of a stable isotope and is relatively environment-friendly". These sentences are cited to a 2006 paper, the abstract of which is online. I've looked at the abstract, and it appears to support part of the first sentence, but not the second sentence - the one after which it appears. Meanwhile, the first part of the sentence, including the density figures, appear to come from the USGS paper, which has not been footnoted in this location at all. It is not clear to me that the fact about minimal radioactivity is sourced to either of these references.
    • I moved the ref up, close to the numbers, and checked it for most of the facts, the low radioactivity is only mentioned as a low activity of the potassium-40 which is present as impurity, I look for a better source or I will remove the radioactivity bit. --Stone (talk) 21:15, 24 February 2010 (UTC)[reply]
  • This phrase under "other uses" - "Concerns about the corrosive action of caesium on spacecraft components, have pushed development in the direction of use of inert gas propellants" - is a verbatim quote from the source (USGS), while other material is a close paraphrase. At the same time, the USGS material has been broken up with this sentence: "It used a method of ionization to strip the outer electron from the propellant by simple contact with tungsten". This fact, however, is in fact not in the USGS study at all, and is therefore completely uncited.

I haven't time to go through everything else, but i think this article has some serious problems, and I would recommend the nominator withdraw it at FAC. I will leave them an message. hamiltonstone (talk) 03:47, 22 February 2010 (UTC)[reply]

  • Comments:
    • Section Compounds; 3rd paragraph, sentence starts "Noteworthy,..." sounds a little awkward. Would "Notably" or just "Note,..." mean the same thing and sound better? If not, I'd like to see it changed some way.
    • Section History; has "first element to be discovered spectroscopically" and then later in the 3rd paragraph "first element to be discovered by spectrum analysis"... assuming these mean the same thing is this an undesirable repetition?
      They do mean the same thing, and I think it ought to be reworded too. I'm outlining a logical flow below that should work, but I'm not familiar with which references are being used to verify which facts (and the computer I'm typing this on is an ungodly slow* thin client, so looking up each reference is unwieldy at best), so I don't feel comfortable implementing it just yet. (*Typing this sentence took me <10 seconds, but it took at least 15 to 20 to display on the screen. :/)
      1. Caesium was discovered in 1860 by Bunsen and Kirchhoff.
      2. Caesium was first isolated from the huge amount of mineral water by the given process
      3. Caesium was identified in the residue by spectroscopy
      4. Caesium was the first element to be so identified.
      5. Caesium was identified, and named for, the blue lines in its emission spectrum.
      {{Nihiltres|talk|edits|⚡}} 17:10, 15 February 2010 (UTC)[reply]
    Tried to rearrange the history section, I hope it has a better flow now.--Stone (talk) 07:37, 16 February 2010 (UTC)[reply]
    • Section Atomic clocks; "...control and regulate information flow on the internet". That sounds interesting to me as a non-chemist layman. But no further information is given. It made me curious. Could it be expanded with a brief sentence explaining how it does this?
      • the source says: The time determined by the Master Clock is then used, through a variety of methods, to set the time for the networks that control cellular telephone transmissions and those that regulate information flow on the Internet. I am not sure how to expand this. Nergaal (talk) 19:33, 15 February 2010 (UTC)[reply]
        • Hmmm. I guess you have a few options; put a {{clarify}} tag on it and hope someone comes along and helps but I guess that will mean it will fail as Featured. You could research it yourself (I've tried a couple of Google searches to see what I can find, but haven't been able to find anything). You could ask at WP:Reference Desk or you could just leave it as it is and let it remain enigmatic :o) The other option is, of course, to remove the claim but that seems a shame as you have a reference for it and it sounds like it would be interesting to our readers once we know what it means. --bodnotbod (talk) 23:59, 15 February 2010 (UTC)[reply]
          • Perhaps this is some help [2] or any of these results [3]. --bodnotbod (talk) 00:04, 16 February 2010 (UTC)[reply]
            • I am not sure I get your point: remove it because it made you curious? Let me think; ummm, no. This article is supposed to present the element and for that it clearly explains that it is used for timing of internet devices; by going deeper and explaining how that is actually done is way besides the point of the article. When an article on caesium clocks will be submitted to FAC, I am sure it will have all those explanations, but now that is not the case. Nergaal (talk) 01:43, 16 February 2010 (UTC)[reply]
              • Removal was only a mild suggestion, one that I basically wrote off as being a bad idea even as I mentioned it, so let's forget about that. What continues to bug me is that the claim apparently is not understood by you and nor has any other editor so far come out who knows what the claim means. From my personal perspective, if I had an article up for review I would be quite keen to ensure that I understood everything in it. But, as I say, it's not a deal-breaker; I wouldn't damn the article for it, so I am quite content if you leave that section as it is. --bodnotbod (talk) 09:47, 16 February 2010 (UTC)[reply]
    • Section Other uses; sentence regarding fibre optics + night vision, no citation is given. --bodnotbod (talk) 11:47, 15 February 2010 (UTC)[reply]
  • Oppose per criterion three:
  • Comment image issues resolved. Эlcobbola talk 15:50, 18 February 2010 (UTC)[reply]
    • File:Cs-137-decay.svg - Data presented should have a source.
    • File:Nistf1ph.jpg - Copyvio. NIST site says "Some of the photographs available through this gallery are owned by the photographer who took the pictures, not by NIST. These photographs are marked as copyrighted..." This image is copyright Geoffrey Wheeler, per this page.
      • I have added the correct author. Are images listed under this news release available for public use?If you go on the subpages you will get a text saying "To download hi-res jpeg versions Shift Left Mouse click on images." Does this imply that they may be used as long as the copyright is stated? Nergaal (talk) 18:51, 15 February 2010 (UTC)[reply]
        • It's not just an issue of attribution. The non-NIST images are not free per that site (they retain restrictions on use), so this image can't be used. Making available a high resolution version doesn't indicate copyright status, but the aforementioned site does state that images without a specific copyright credit are NIST works. Thus the image here might be ok (I'd have to look a bit more closely), but the images here are not ok (they credit a copyright holder). Эlcobbola talk 23:51, 15 February 2010 (UTC)[reply]
    • File:Usno-mc.jpg - Source does not attribute an author. How can we confirm federal authorship? Is there a general disclaimer stating all media used on this site are PD?
    • File:Bunsen-Kirchhoff.jpg - Unsupported PD claim based on life of subject, not of author. Reasonable scenarios exist which would make this not PD (for example, 25 year old author took this image in 1885. Author thus born ca. 1860, could have died in 1941, aged 81. Image would not be PD in this circumstance). How can we confirm the author indeed died 70 or more years ago? Эlcobbola talk 17:30, 15 February 2010 (UTC)[reply]
      • This is the original website; anybody willing to email them about using this image (and perhaps some other ones) on wikipedia? Nergaal (talk) 18:42, 15 February 2010 (UTC)[reply]
      • While I can't conclusively say that the image is PD, I find the assertion that it's not PD highly dubious. What you're saying is that if the image was taken a mere two years before Kirchhoff's death, and the author was a rather young 25 at the time, then it will be PD only one year from now based on the death plus seventy years rule. Given that Kirchhoff and Bunsen are only middle-aged at worst in that image, I would find it quite odd if it was taken in 1885, because Bunsen would then be quite well-preserved for a 74-year-old man. I would find it much more likely that the picture was taken 1875 or earlier, in which case the hypothetical 25-year-old photographer would have to make it to 91 for the image to not yet be in the public domain now by the death-and-seventy-years rule. That's also completely ignoring the change in copyright law over time; IANAL, but there may be a case for it to be public domain either way. Yes, we should try to find more data on when the image was made and by whom, but it's highly unlikely that the image is not PD by now. {{Nihiltres|talk|edits|⚡}} 21:26, 15 February 2010 (UTC)[reply]
        • Please read critically. I've said the claim is unsupported, not that it's not PD. Verifiability, not truth, is the threshold of inclusion. I've merely given a scenario, however unlikely, that could cause the claim to be false (i.e. to demonstrate the folly of relying on the subject's date of death). Speculation is not acceptable in establishing copyright status. Media seeking inclusion in Wikipedia's best work must have verifiable, not speculative, support. Эlcobbola talk 23:51, 15 February 2010 (UTC)[reply]
          • The original publishers state The Annenberg Rare Book And Manuscript Library, which houses these images, does not hold copyright to them. In making them accessible through SCETI, the library acts as owner of these physical objects only. It assumes no responsibility for copyright, where applicable. To obtain letters of permission for the publication of these materials, write directly to Lynne Farrington, Curator of Printed Books, lynne@pobox.upenn.edu. If this doesn't work, is File:Kirchhoff Bunsen Roscoe.jpg ok? Nergaal (talk) 01:30, 16 February 2010 (UTC)[reply]
  • Comment—Overall I support this article as it looks well-researched and meets most of the FA criteria. I do have a few minor issues:
    • "Caesium is a very soft, very ductile..." Is there a ductility value for Caesium? Pehaps compare it to other metals as per the ductility article.
      • I had no idea that ductility can be quantified. If that is the case it may be worth adding some entry into the element infoboxes. Nergaal (talk) 07:00, 20 February 2010 (UTC)[reply]
        • Does Caesium really have a Mohs hardness of 0.2? That really is extraordinarily soft. Interesting.—RJH (talk)
    • There are some seemingly unnecessary instances of 'even', 'On the other hand', 'In contrast', 'originally' and 'in reality'. In many cases, removing these shouldn't hurt and will tighten up the text.
    • The relevance of much of the sentence that begins "Francium may be more electropositive..." is unclear to me.
    • The Production section mentions 'direct reduction' but doesn't appear to explain it.
      • It is covered under Albeit not commercially feasible, the ore mineral may be directly reduced by heating it with calcium, potassium, or sodium metal in a vacuum or an inert atmosphere, which yields an impure caesium metal (right after the second method is detailed) Nergaal (talk) 06:53, 20 February 2010 (UTC)[reply]
        • Sorry, I missed that because it is in a paragraph that starts with a different subject.—RJH (talk)
    • Is there any information about why caesium was used for the definition of a second and also why caesium is specifically used for atomic clocks?
      • Because of it exists as a single isotope, it is easy to vaporize (the reading is done in the gas/plasma pahse), and I think because it has a heavy nucleus. I need to find some clear references about this though, as rubidium clocks (only recently created) appear to be more precise. Nergaal (talk) 06:53, 20 February 2010 (UTC)[reply]
        • Okay. I think that would be of interest to some readers.—RJH (talk)
          • This discussion looks like a good copy of a similar discussion on the German wiki for the FA status there. 1) Hydrogen similar atoms are not the only ones possible for clocks and the planned systems use other elements. 2) The used transition is not more stable than others and can be influenced by magnetic fields. 3) The low boiling point is not the good thing, because even high melting metals form atomic beams, but the fact that the atomic beam is at a low temperature and therefore has a minimal broadening. 4) Several isotopes are not a problem due to the wide distance between the lines compared to the observed transits. 5) The point which is the only valid is that the 9GHz was right at the boarder of what normal electronics could do and this was the way to go because the highest possible frequency gives the most precise results.--Stone (talk) 19:39, 21 February 2010 (UTC)[reply]
            • Per chance, is there a synopsis and a cite available for the article?—RJH (talk)
    • The article includes both em-dashes (e.g. Occurrence section) and en-dashes (E.g. Petroleum exploration) in sentences. Please be consistent and use one or the other, as per the MoS recommendation.
    • The article might mention that caesium is produced by the slow neutron capture process (S-process) in stars; primarily AGB stars.

This looks decent:

Busso, M.; Gallino, R.; Wasserburg, G. J. (1999). "Nucleosynthesis in Asymptotic Giant Branch Stars: Relevance for Galactic Enrichment and Solar System Formation" (PDF). Annula Review of stronomy and Astrophysics. 37: 239–309. Retrieved 2010-02-20.

There's an example on p. 256, a table of short-lived isotopes on p. 280, a model graph on p. 291. This ref. includes some discussion of caesium:

Lugaro, Maria. "Isotopic Compositions of Strontium, Zirconium, Molybdenum, and Barium in Single Presolar SiC Grains and Asymptotic Giant Branch Stars". Astrophysical Journal. 593: 486–508. Bibcode:2003ApJ...593..486L. doi:10.1086/376442. {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)

Here's a ref. on isotopic evidence from the early Solar System:

Hidaka, H.; Ohta, Y.; Yoneda, S.; Delaeter, J. R. (July 2000). "Isotopic Evidence of Live Cesium-135 in the Early Solar System" (PDF). Meteoritics & Planetary Science. 35: A72. Bibcode:2000M&PSA..35Q..72H. Retrieved 2010-02-20.

Interestingly, there was also a study of Caesium in the atmosphere of a brown dwarf, where it was used to probe the atmospheric chemistry:

Griffith, Caitlin A.; Yelle, Roger V. (March 2000). "Equilibrium Chemistry in a Brown Dwarf's Atmosphere: Cesium in Gliese 229B". Bibcode:2000ApJ...532L..59G. doi:10.1086/312550. {{cite journal}}: Cite journal requires |journal= (help)

But that's a little off topic.—RJH (talk)

      • Would this be OK? Caesium-133 is produced in in stars by the slow neutron capture process (S-process starting from lighter elements.
Ephraim, Bernard; Pagel, Julius (1997). Nucleosynthesis and chemical evolution of galaxies. Cambridge University Press. p. 87. ISBN 9780521559584.
        • Well it's a true statement, but I think that multiple caesium isotopes are made in that manner, which decay shortly thereafter. I checked the following source and it looks like Caesium-133 is also produced by the r-process, so supernovae could also be added to the list.
          Arnett, David (1996). Supernovae and Nucleosynthesis: An Investigation of the History of Matter, from the Big Bang to the Present. Princeton University Press. p. 527. ISBN 0-691-01147-8.
        There's a comparable example in the last paragraph of Xenon#Occurrence and production.—RJH (talk)
    • There is information available about the solar abundance of caesium. I believe it differs from the abundance in the Earth's crust. Abundances of the elements (data page).
    • Some of the ref. have slight irregularities. Holleman... ends with a semi-colon; Andreev... ends with a comma; Polyak... and Sovey... end with a double period; Kirchhoff... and Salbu... have double-commas; Timur... and Johnson... don't have periods after the initials
    Thanks.—RJH (talk) 23:41, 19 February 2010 (UTC)[reply]
  • Conditional support - COI notice: I de-stubbed this article several years ago but had nothing to do with the FA-improvement drive. Per WP:CHEMNAME, isotope labeling should be in the form of caesium-133, not 133Cs (except inside equations). Dab link to coordination needs to be fixed. External links look good. All images have alt text. Referencing looks good. Prose quality is good. Seems to cover all the major aspects of the subject. My support is conditioned on fixing the isotope labeling issue. --mav (Urgent FACs/FARs/PRs) 16:24, 20 February 2010 (UTC)[reply]
The Featured Articles Plutonium Uranium Helium Technetium follow the rule while Germanium Zinc Niobium Yttrium Iridium Titanium Xenon Oxygen use the isotope labeling like in the caesium article. Should we change the naming convention to allow both in a consistent way or should we change all?--Stone (talk) 18:19, 20 February 2010 (UTC)[reply]
To me the cited IUPAC document doesn't strictly suggest to use the expanded version. I preferred to use the symbol version here because I thought it would make the prose less repetitive, but if you guys think the opposite I would be fine with changing it. Nergaal (talk) 18:53, 20 February 2010 (UTC)[reply]
In general, I think it's more natural, simpler to read, etc. to use the recommended system ("caesium-133") than the short system ("133Cs") but there are times where it might be preferable to use the short system, e.g. in Germanium where there is a list of 5 naturally-occuring isotopes in prose. Saying "70Ge, 72Ge, 73Ge, 74Ge, and 76Ge" seems nicer than saying "germanium-70, germanium-72, <germanium-73, germanium-74, and germanium-76". For such lists, I think a short form might be justified, but there are plenty of places where we really ought to use the longer, clearer form. {{Nihiltres|talk|edits|⚡}} 19:05, 20 February 2010 (UTC)[reply]
This sounds like a very good suggestion. --Stone (talk) 19:30, 20 February 2010 (UTC)[reply]
I think this is reasonable. --mav (Urgent FACs/FARs/PRs) 04:05, 21 February 2010 (UTC)[reply]
All FA element articles should be made consistent with the MOSCHEM guidelines. But some leeway can be given when mentioning many isotopes in the same sentence. --mav (Urgent FACs/FARs/PRs) 04:08, 21 February 2010 (UTC)[reply]
I think I changed all the instances of 13xCs to caesium-13x outside the isotopes section. Did I miss anything? Nergaal (talk) 16:53, 21 February 2010 (UTC)[reply]
  • Oppose. I feel like there are still quite a few problems in this article. Here a couple of examples I stumbled upon skimming through the article:
  • "Mercury is the only metal with a melting point lower than caesium (the radioactive element francium may also have a lower melting point[5]).[6]" Seems like an odd sentence. Does francium's melting point vary or is it simply unknown? I think this would sound better: "Mercury, and perhaps francium, are the only metals with melting points lower than caesium".
    See reply to next point. {{Nihiltres|talk|edits|⚡}} 17:11, 26 February 2010 (UTC)[reply]
  • The same goes for these sentences: "Caesium is the most electropositive stable chemical element.[6] Francium may be more electropositive, but this has not been experimentally measured due to its high radioactivity. Measurements of the first ionization energy of Francium suggest that relativistic effects may lower its reactivity and raise its electronegativity above that expected from periodic trends." Also, the last sentence doesn't seem that relevant to caesium.
    I've attempted to clarify these off-topic bits by changing them into notes, since they're mostly asides anyway. It should read more naturally now. {{Nihiltres|talk|edits|⚡}} 17:11, 26 February 2010 (UTC)[reply]
  • "Using hot sulfuric acid (35% to 45%) instead yields a solution from which caesium alum (CsAl(SO4)2·12H2O) is precipitated, roasted this with 4% carbon, and then leached, to yield a Cs2SO4 solution which subsequently converted into CsCl.[3]" I don't understand this sentence.
(interjection) I think this sentence arose because I raised concerns about plagiarism / close paraphrasing of the USGS source, and an editor - i assume Nergaal has tried to modify the text to move away from the original. As i said before, sometimes it is best to quote verbatim, with quote marks or blockquotes, rather than dicking around with the text and causing comprehension problems. regards, hamiltonstone (talk) 23:21, 21 February 2010 (UTC)[reply]


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