Talk:Europium/Archive 1

Source needed
"A salt of Europium is a component of the newer phosphorescent powders and paints, some of which will glow for days after a few minutes of exposure to light." I don't think this is possible (allthough it may be). I have commented it out in article page (< !-- -->). Please find some relevant source. --Borislav Dopudja 16:09, 14 September 2006 (UTC)

How is Europium used in screening for Down's Syndrome?--Syd Henderson 17:54, 1 October 2006 (UTC)

In a very generic way: by tagging, with europium, the antibodies for a relevant protein; reacting the antibodies with a serum sample; and then testing for presence of europium. Fortunately, the concentration of various proteins at specific times in pregnancy give a statistical signal for Down's syndrome. See (PDF):. At any rate, it's very misleading to give such attention to Down's syndrome and this whole sentence is clumsy. Also United Nuclear appears to proudly sell a new line of Europium glow powder/paint with a shine-time of 12 hours: --Tteravai (talk) 03:38, 27 August 2008 (UTC)

Vague Phraseology
What is meant by the comment: "...deliveries of the metal element in solid form..." in the Characteristics section? I'm certain that the author can come up with a better way of phrasing this. R N Talley (talk) 19:06, 23 December 2008 (UTC)
 * I've changed "deliveries" to "samples". --Itub (talk) 20:22, 23 December 2008 (UTC)

Water is a liquid
H2O (g) is probably a typo.

While it is possible that H2O (aq) (i.e. water vapor in a solution of water) may be what actually reacts in the 2 Eu + 6 H2O, I suspect that 2 Eu (s) + 6 H2O (l) →  ... would suffice.


 * Water vapor dissolved in water? Heh... never heard of that. Wouldn't it just condense immediately? Anyway, fixed all the lanthanoid articles that had this error (it is clearly stated that it's cold water and hot water, so I'm assuming that it can't be referring to steam -- besides, the point was that these metals are quite reactive towards water, which wouldn't be the case if they required &gt; 100°C to react). The joys of copy-n-paste... &mdash;Tetracube (talk) 03:40, 18 September 2009 (UTC)

Error in vapor pressure?
In the info box, shouldn't the vapor pressure at 1796K, which is nearly the boiling point, be closer to 100kPa ~1atm than 1kPa?Wikimedes (talk) 09:57, 10 June 2011 (UTC)
 * There was a typo in the code of the infobox that messed up the pressure scale of the table. Fixed. Thanks! Materialscientist (talk) 10:30, 10 June 2011 (UTC)

looks like some people were interested, but not TOO interested
Eu complexes (some details!) in the euro notes Double sharp (talk) 02:58, 25 June 2013 (UTC)

the lead
needs expansion (see Samarium for an example). Double sharp (talk) 15:41, 26 August 2013 (UTC)

Infobox
Infobox says it's silvery white. Pictures indicate it's not. Was probably copied from somewhere else and not changed. Anyone know how to properly describe it? --Jinman11 (talk) 08:57, 13 May 2010 (UTC)
 * From what I can tell, it is silvery white, but is almost impossible to observe pure, since it oxidizes in seconds (like calcium). The samples pictured here appear to be slightly oxidized; even a thin layer can drastically change the appearance. As with other metals (like bismuth, niobium, titanium, and aluminum), the oxide thickness determines the apparent color of the sample, which can vary widely. Here is a more heavily oxidized piece of Eu that appears dark bluish-green: and here is one that looks more light green: . Stonemason89 (talk) 18:18, 15 May 2010 (UTC)
 * Infobox changed to reflect the fact that Eu is rarely seen without an oxide coat. Stonemason89 (talk) 18:23, 15 May 2010 (UTC)
 * Yeah, it is definitely silvery-white, but oxidizes inconveniently quickly. Does anybody have a CC-BY-SA compatible picture of the oxide? - 2/0 (cont.) 19:10, 15 May 2010 (UTC)
 * Sure, we have File:Eu2O3.powder.jpg, and it is white and there is no doubt about it (pale red color of some powders might be due to strong luminescence of Eu oxide powder under UV light). There is also little doubt that pure Eu is white. The Eu in images is handled in Ar, but I this won't save from surface oxidation. I don't have a good answer and will search for it when time permits. An explanation is welcome.

UV 'light'? Oh, dear ...

Materialscientist (talk) 01:22, 16 May 2010 (UTC)
 * The oxide is white in bulk (as are many other oxides) but sufficiently thin layers of it can and do display colors. See anodizing for more information, specifically the sections on titanium and niobium. Any transparent material can display such colors if it is deposited in sufficiently thin layers. The underlying principle is the same as that used in manufacturing dielectric mirrors. Stonemason89 (talk) 18:50, 16 May 2010 (UTC)
 * I thought about that, but my concern was the rough surface of the material which would suppress interference (angle change constantly and thus reflected color). Yes, it should be related to the color of the oxide, and the color changes on those chunks, but I'm not sure it is just thin film interference. Materialscientist (talk) 22:29, 16 May 2010 (UTC)
 * Yes, but even for rough surfaces there's still an average angle of reflection, so the overall apparent color might be related to this average angle? Maybe I'm just grasping at straws here. For what it's worth, the image description for Eu-block.jpg says that it is polycrystalline, which would imply that its surface is not truly rough but is rather made up of many tiny, but smooth, facets.Stonemason89 (talk) 00:03, 17 May 2010 (UTC)

It shouldn't be THAT difficult to observe in a vacuum glass container, surely? Isn't that what one of the pictures shows? — Preceding unsigned comment added by 92.2.221.112 (talk) 19:13, 1 February 2014 (UTC)

"Color TV screens contain between 0.5 and 1 g of europium"
The article says, "Color TV screens contain between 0.5 and 1 g of europium." Really? That much? That sounds high.

It has a citation to http://www.maneyonline.com/legacy/imr/1992/00000037/00000001/art00015 which is a dead link. Archive.org has a copy here https://web.archive.org/web/20121024023056/http://www.ingentaconnect.com/content/maney/imr/1992/00000037/00000001/art00015 (which I also saved here) but it's just an abstract of a paywalled article. NCdave (talk) 05:17, 10 February 2015 (UTC)
 * I've found full text here (24 Mb). It says "color TV screen requires approximately 5–10 g yttrium oxide and 0.5–1 g europium oxide (Jackson and Christiansen 1993)", which doesn't sound unreasonable to me - back then a phosphor layer was often coated via some crude chemical procedure (roughly like painting) and consumed much material. Materialscientist (talk) 06:52, 10 February 2015 (UTC)

External links modified
Hello fellow Wikipedians,

I have just added archive links to 2 one external links on Europium. Please take a moment to review my edit. If necessary, add after the link to keep me from modifying it. Alternatively, you can add to keep me off the page altogether. I made the following changes:
 * Added archive https://web.archive.org/20150610213313/http://wwwndc.jaea.go.jp/NuC/index.html to http://wwwndc.jaea.go.jp/NuC/index.html
 * Attempted to fix sourcing for http://vector.umd.edu/links_files/Extractive%20Metallurgy%20of%20Rare%20Earths%20(Gupta).pdf

When you have finished reviewing my changes, please set the checked parameter below to true to let others know.

Cheers. —cyberbot II  Talk to my owner :Online 00:48, 26 August 2015 (UTC)

Untitled
Article changed over to new WikiProject Elements format by schnee. Elementbox converted 11:19, 10 July 2005 by Femto (previous revision was that of 13:44, 9 July 2005). 9 July 2005

Similar size of Eu2+ and Ba2+
This is not true. The ionic radius of Eu2+ is similar to the one of Sr2+ (e.g. for eightfold coordination: 0.126 nm for Sr2+ and 0.125 nm for Eu2+). The ionic radius of Ba2+ with eight ligands is 0.142 nm. All values are taken from the paper of Shannon. — Preceding unsigned comment added by 130.75.157.53 (talk) 11:46, 23 September 2015 (UTC)

Similar hardness to lead
If so, it can't be 'moderately hard' - that's a contradiction in terms.

Discovery vs. isolation
Europium was first observed spectroscopically in 1896, but does that not count as the discovery? The page on 1901 in science says that europium was discovered then. Other elements (helium, holmium, gadolinium, and probably some others) are listed by when they were first observed spectroscopically. Could we please have consistency with Eu? Squee3 (talk) 19:51, 28 December 2016 (UTC)
 * Wikipedia is not writting the history of the discovery of elements, it only reports it like it is written in books and other encyclopedias. So what do the other sources tell us? --Stone (talk) 20:57, 28 December 2016 (UTC)
 * They say 1896 or 1901. I don't want any articles here on the wiki changed regarding this anymore, and I would actually like this post to be deleted. Squee3 (talk) 17:00, 7 January 2017 (UTC)

Loparite-(Ce)
The correct mineral name is loparite-(Ce); a mineral named "loparite" does not exist. Also, bastnasite-group minerals are carbonates, xenotime is a phosphate, but loparite is NOT any of those, as it is OXIDE. Please fix this. Eudialytos (talk) 15:55, 10 June 2017 (UTC)
 * ✅ Double sharp (talk) 03:57, 11 June 2017 (UTC)

"This is because europium is divalent in the metallic state"
Metallic state is understood as essentialy ZEROvalent. Eudialytos (talk) 19:24, 23 August 2017 (UTC)
 * Strangely, this is a fairly common wording, and simply means that metallic Eu has about two electrons delocalised per atom instead of the three of most of the other lanthanides. Yb is the other one that does this. Double sharp (talk) 23:45, 23 August 2017 (UTC)
 * This case is similar to sublimation - a term used to (wrongly) describe both solid --> gas AND gas --> solid transformation; while the fist process is, indeed, a sublimation, the other one is DE-sublimation (or condensation). Having 2 or 3 delocalized electrons does not yet mean there is a bonding, and valency is used to describe bonds (although, usually, towards other = electronegatively different elements).Eudialytos (talk) 20:06, 29 August 2017 (UTC)
 * Yes it does mean there is bonding, as this attraction of the delocalised electrons to the ions that remain is precisely metallic bonding. Since these ions are Eu2+, the wording makes some sense, and I suspect it gets used because it gets irritating to say that Eu is a "metal with about two electrons delocalised per atom" instead of a "divalent metal", even though it is a bit of an abuse of language. Double sharp (talk) 23:26, 29 August 2017 (UTC)

Wrong bastnäsite formula/identity
"Bastnäsite is an orthophosphate mineral LnPO4" is obviously wrong - the formula given is that of the MONAZITE group of minerals; bastnäsite-(Ce)'s formula is (Ce,La,Nd,...)(CO3)F.Eudialytos (talk) 18:57, 15 October 2017 (UTC)

Wrong xenotime formula/identity
1. There is no such mineral like xenotime; this name refers to a GROUP; the correct name is xenotime-(Y). Also, xenotime is an important source of yttrium, ytterbium, dysprosium, gadolinium, but not necessarily of europium.

2. Xenotime-(Y)'s formula is YPO4.Eudialytos (talk) 19:01, 15 October 2017 (UTC)

To fix
Why does one heading read "Chalcogenides and pnictides," then the word "pnictides" is mentioned nowhere in that section (and, in fact, it is not mentioned anywhere in the article)? 173.88.246.138 (talk) 04:39, 18 February 2021 (UTC)