Talk:Cerium/Archive 1

Liquid Range
The line ' ''Cerium has the longest liquid range of any non-radioactive element: 2648 C° (795 °C to 3443 °C) or 4766 F° (1463 °F to 6229 °F). (Thorium has a longer liquid range, but is radioactive)'' ' troubles me as whilst it is factually correct, it is a forced distinction that seems to imply (by association) that the liquid range of an element is somehow intrinsically related to its radioactivity. If thorium were synthetic, then it would be important to make a natural/synthetic distinction, however this is not the case. Accordingly, I will be bold and change this statement to 'Cerium has the second-longest liquid range of any element: 2648 C° (795 °C to 3443 °C) or 4766 F° (1463 °F to 6229 °F) (Thorium has the longest liquid range.)' Eutactic (talk) 02:39, 2 June 2010 (UTC)
 * There were several ways to fix that, I would do it differently, but your way is Ok - length of the liquid range is a very minor distinction, IMO; it is not like an olympic gold medal, or highest melting point. Materialscientist (talk) 03:42, 2 June 2010 (UTC)

Electron Configuration
The electron configuration is given as [Xe]4f26s2. Should it not be [Xe]4f15d16s2? Source: http://www.webelements.com/cerium/atoms.html. I'm not a chemist so perhaps there is some subtlety I am missing. —Preceding unsigned comment added by 142.103.140.57 (talk) 18:47, 31 August 2010 (UTC)
 * A general answer is, it is not obvious which electronic configuration is more stable (for a free atom), thus a reliable reference is required. Webelements per se is not such a source, unless they cite a proper reference. Materialscientist (talk) 22:31, 31 August 2010 (UTC)


 * Ok, thank you. should the Electrons Per Shell be changed to be consistent with the configuration? "2, 8, 18, 19, 9, 2" to "2, 8, 18, 20, 8, 2", or is the discrepancy left to point to the uncertainty of the actual configuration? —Preceding unsigned comment added by 142.103.140.57 (talk) 20:04, 1 September 2010 (UTC)
 * I have corrected the infobox data to "2, 8, 18, 19, 9, 2" per quoted source, which is also supported by (page 1-14).

Orphaned references in Cerium
I check pages listed in Category:Pages with incorrect ref formatting to try to fix reference errors. One of the things I do is look for content for orphaned references in wikilinked articles. I have found content for some of Cerium's orphans, the problem is that I found more than one version. I can't determine which (if any) is correct for this article, so I am asking for a sentient editor to look it over and copy the correct ref content into this article.

Reference named "Emsley": From Ruthenium:  From Pnictogen:  From Tellurium:  From Chromium:  From Tantalum:  From History of the periodic table:  From Osmium:  From Astatine: </li> <li>From Rhenium: </li> <li>From Protactinium: </li> <li>From Erbium: </li> <li>From Iridium: </li> <li>From Cornubian batholith: </li> <li>From Actinide: </li> </ul>

I apologize if any of the above are effectively identical; I am just a simple computer program, so I can't determine whether minor differences are significant or not. AnomieBOT ⚡ 23:27, 2 February 2013 (UTC)

Physical properties / Allotrope descriptions
I had trouble understanding some of the description of the solid-state phase changes, so I dug out some old references and extended the description here. I also did some formatting and rearranging. An unfortunate consequence of trying to remain correct is that I have had to qualify temperatures with many "approximately"s and "about"s. Those transformation temperatures can really only be accurately stated in the context of specific cooling or heating rates. I have not seen any references with detailed time-temperature-transformation plots, nor continuous cooling transformation plots. The one detail I removed was the statement about transformation to &alpha; being complete only at -269&deg;C. I cannot find that statement published, but I am certain it would only be correct under specific experimental conditions and not a general property. Alloy730 (talk) 15:10, 10 December 2013 (UTC)

Transition to C-class
Don't any one of you think that this article is long and has enough meaningful content to be upgraded into a C-class article? I mean, I've reviewed the criteria, and I suppose that this would be a good addition to the C-class articles. Even compared to other C articles, it seems to be comparable and it surpasses all of the wikipedia criteria for being a C article. That's just my opinion, though. --Geo7777 (talk) 15:43, 1 May 2011 (UTC)
 * Right, although the referencing is very weak it might be OK to give it a C-Class rating--Stone (talk) 21:01, 1 May 2011 (UTC)
 * I think WP:ELEM is rather strict with the rating of articles compared with most other WPs, say element 126 would be B-class if not for the referencing. But then, hey, this is what makes our articles properly excellent when they become FA, right? :-) Lanthanum-138 (talk) 12:55, 11 May 2011 (UTC)
 * Although I do agree that you do need to get used to this state of affairs when you first start off with us. When I first started I was at first upgrading articles' ratings without doing anything to them first because I felt they weren't that bad. Unfortunately, that wasn't to last, although my upgrades of Mt and Rg from Start to C still stand :-). Lanthanum-138 (talk) 12:58, 11 May 2011 (UTC)
 * Not anymore. Double sharp (talk) 07:39, 23 December 2011 (UTC)
 * ...although they are both GAs now. Double sharp (talk) 11:29, 17 July 2014 (UTC)

Is this element radioactive?
When I read it, I thought it was radioactive, and I thought it was element 96. I thought it was named after Pierre Curie. I'm confused.

- Erbium Is Awesome (talk) 03:17, 26 April 2015 (UTC)
 * You're thinking of curium. Cerium is element 58, and was named after the dwarf planet Ceres. Double sharp (talk) 03:37, 26 April 2015 (UTC)

Cerium 140 Spontaneous fission??
On the isotopes list, the decay mode for Cerium 140 is spontaneous fission.

Shouldn't it be stable?
 * Right under that list: "Decay modes in parentheses are predicted, but have not yet been observed". And the half-life is expected to be extremely long, so that we can't yet observe it. Double sharp (talk) 18:29, 24 July 2015 (UTC)

Early changes
Article changed over to new WikiProject Elements format by Fonzy, Gaz, Mkweise, and Dwmyers 15:01 Mar 3, 2003 (UTC). Elementbox converted 10:53, 10 July 2005 by Femto (previous revision was that of 13:46, 9 July 2005).

Information Sources
Some of the text in this entry was rewritten from Los Alamos National Laboratory - Cerium. Additional text was taken directly from USGS Cerium Statistics and Information, USGS Periodic Table - Cerium, from the Elements database 20001107 (via dict.org), Webster's Revised Unabridged Dictionary (1913) (via dict.org) and WordNet (r) 1.7 (via dict.org). Data for the table was obtained from the sources listed on the subject page and WikiProject Elements but was reformatted and converted into SI units. --

Talk
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It seems unlikely to me that Berzelius would have named Cerium after an asteroid. Ceres was goddess of agriculture (or grain) and the element is one of the rare-earth elements; also Tellus, earth goddess was sometimes confounded with Ceres. Seems to me more likely that the discovery of the asteroid brought Ceres to Berzelius' attention and so stimulated him to name the element after Ceres - but I do not, of course, know. Pdn 04:07, 20 Mar 2005 (UTC)

Certainly I have always read that it was named after the asteroid- but I guess we can't be totally sure. If you look in Chemistry of the Elements (Greenwood & Earnshaw), a pretty authoritative text, it is given the asteroid explanation. I actually don't find it that surprising- from what I remember of astronomy, Ceres was the first asteroid to be discovered, so there was probably a lot of excitement aoming scientists at the time. Walkerma 23:14, 22 Mar 2005 (UTC)

The asteroid was named after the goddess, and then the element was named after the asteroid. The same sequence occured for palladium and the asteroid Pallas.

The element is described as silvery white, but the picture looks brownish black...
 * Well, it is rather reactive. You're not going to have very long to admire the shine, I'm afraid. Double sharp (talk) 16:20, 9 July 2016 (UTC)

Decompose
"Cerium decomposes slowly in cold water and rapidly in hot water."

What does "decompose" mean when referring to an element? RodC 11:49, 25 May 2005 (UTC)

You're quite right, an element can't chemically decompose (unless going to s simpler allotrope), but sometimes people use the word rather casually to mean "react"- in the sense here that the physical structure of the cerium is falling apart. I've altered the text to say "oxidise." Walkerma 17:44, 25 May 2005 (UTC)

Looks like it's been changed back to "decompose". I don't like the casual use of the word at all. Words should be used specifically as their denotations indicate. —Preceding unsigned comment added by 76.118.30.201 (talk) 21:58, 24 May 2009 (UTC)


 * Looks like language issue (casual use). I changed a bit and welcome rewriting. In other instances, sublimation could be called decomposition, though it does not need chemical reaction.Materialscientist (talk) 01:19, 25 May 2009 (UTC)

Reaction w/ Zinc, Bismuth & Antimony
Anyone have a source for the statement about cerium reacting with zinc, bismuth and antimony? This sounds false to me - I would expect them to alloy, potentially, but not to chemically react. dryguy 13:47, 17 January 2006 (UTC)


 * The following PDF verifies this fact. www.espi-metals.com/msds's/cerium.pdf. It doesn't seem that unlikely that it would react; nickel, palladium, and platinum react exothermically with aluminum to form metal aluminides.

Thanks for the MSDS. I was really wondering if anyone knows of a peer reviewed publication mentioning specific cerium compounds of zinc, bismuth or antimony, or reporting measurements of the heat output when cerium is mixed with said elements. Unfortunately, I have seen MSDS sheets before with wildly incorrect statements; I have the impression that there is no process to review them for accuracy. dryguy 23:35, 5 May 2006 (UTC)

"compression or cooling of the metal can change its oxidation state from about 3 to 4".

I don't understand the "about" bit... I think clarification is in order. 203.118.183.221 09:19, 9 August 2006 (UTC)

The word "It" is unclear in these two sentences in "Notable Characteristics": "Among rare earth elements only europium is more reactive. It tarnishes readily in the air." Please change "It" to Cerium or other if needed.Tullywinters (talk) 18:37, 29 January 2008 (UTC)

I have to admit
that part of the article is somewhat of a lie to children. I feel slightly guilty about it, but if Greenwood and Earnshaw are fine with it, it should not be a problem. But I will have to explain briefly what the problem is. Akio Kotani once wrote that "there is no genuine example of cerium(IV)", and that is because, even in seemingly well-behaved compounds like CeO2, cerium does not quite lose its hold on the last electron, and instead its valence is somewhere between +3 and +4 on average, never quite getting to the top end like one would think it should. This also shows in the electronic structures of its compounds, such as cerocene. So I will have to add a little section talking about this problem with calling the higher oxidation state of cerium "cerium(IV)". Double sharp (talk) 06:50, 25 July 2016 (UTC)
 * OK, added. Double sharp (talk) 07:07, 25 July 2016 (UTC)

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Tarnishes rapidly or slowly?
The essay is contradictory on this. Needs to be fixed. Isambard Kingdom (talk) 09:13, 28 March 2017 (UTC)
 * I've removed the qualitative slow/rapid description. Poking around the internet, I can find a wide variety of qualitative descriptions on this, not all consistent, so removed. Isambard Kingdom (talk) 13:02, 28 March 2017 (UTC)

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Removing my revisions
I just wanted to repeat (as my revisions were removed...), that names like "monazite" or "bastnäsite" are wrongly used here, because these are mineral GROUP names and not mineral (species) names. The correct ones are, monazite-(Ce), bastnäsite-(La), etc. My revisions DID HAVE references, but I assume there is Wikipedia AND mineralogy, right?Eudialytos (talk) 20:05, 26 September 2018 (UTC)

Misch metal was very important in Steelmaking
Cerium, Tellurium, and Magnesium in modern metallurgy is added to cast iron which has higher carbon content. Normally the carbon precipitates in stringers that propagate cracks. The above metals modify the carbon into tiny round balls that stop cracks, increasing usable strength. Cerium is usually fed as Misch Metal, the mixed reduced rare earth ore, of ~15% Cerium and other rare earths metal and Thorium which are inoccuos or improve iron carbon structure. Expensive separation of Rare Earth metals balancd by easy access to Misch metal. Reason Rare Earths were no longer mined in US was fall of US steel industry. Magnesium is also used for that purpose (50 ppm) but boils 900 degrees before iron melts so alloying TaylorLeem (talk) 01:15, 28 September 2020 (UTC)