Talk:Cerium

Tarnishes rapidly or slowly?

"Immediately after lanthanum, the 4f orbitals suddenly contract and are lowered in energy to the point that they participate readily in chemical reactions;"

Isn't this the exact opposite of what you want to say? The lanthanide contraction makes the 4f orbitals less likely to participate in chemical reactions, not more likely,72.200.200.2 (talk) 02:31, 5 April 2019 (UTC)

Well, I have corrected it since then (actually it happens already at La, not after La), but the point is correct: up till barium 4f is too high up to participates. At the early lanthanides it contracts and is lowered to the point that allows ready participation. Then as you progress through the lanthanide series they contract further than that and it becomes harder and harder to use them until ytterbium. At lutetium it becomes impossible. Double sharp (talk) 12:38, 26 January 2021 (UTC)

How hard is cerium? It cannot simultaneously be soft enough to cut with a knife and have a hardness similar to silver.

In the first paragraph I read: and it is soft enough to be cut with a steel kitchen knife

And in the "Physical" section I read: It is a ductile metal with a hardness similar to that of silver. I know silver cannot be cut with a knife. This statement has a credible citation labelled with the number 5.

I don't personally have any metallic cerium to try, but one or the other of these statements is true, but not both. I would tend to go with the one that has the citation, rather than the one labelled "citation needed". — Preceding unsigned comment added by Frostybeard (talk • contribs) 08:20, 22 January 2022 (UTC)

Section on Ce+4 not existing

I've removed this section: Despite the common name of cerium(IV) compounds, the Japanese spectroscopist Akio Kotani wrote "there is no genuine example of cerium(IV)". The reason for this can be seen in the structure of ceria itself, which always contains some octahedral vacancies where oxygen atoms would be expected to go and could be better considered a non-stoichiometric compound with chemical formula CeO_2−x. Furthermore, each cerium atom in ceria does not lose all four of its valence electrons, but retains a partial hold on the last one, resulting in an oxidation state between +3 and +4. Even supposedly purely tetravalent compounds such as CeRh₃, CeCo₅, or ceria itself have X-ray photoemission and X-ray absorption spectra more characteristic of intermediate-valence compounds. The 4f electron in cerocene, Ce(C
₈H
₈)
₂, is poised ambiguously between being localized and delocalized and this compound is also considered intermediate-valent. because the sources do not appear to endorse it. And I can't find the opening quote anywhere. Jo-Jo Eumerus (talk) 21:27, 23 January 2022 (UTC)

Pinging Double Sharp who added this section a few years ago; perhaps they can clarify. Jo-Jo Eumerus (talk) 21:31, 23 January 2022 (UTC)

It is right there. From the transcript in the RSC podcast: Indeed the great Japanese spectroscopist Akio Kotani once wrote that 'there is no genuine example of Cerium 4'. (That's how you say "Ce(IV)" out loud; presumably whoever wrote the transcript was not aware of this.) For ceria, we have from that source: Ceria is also very hard which has made it a useful roche or polish for lens. If you happen to want to grind or polish your own telescope, then cerium dioxide is probably what you will use. But what makes the oxide really interesting is it misbehaves. Although the formula may appear to be CeO₂, one cerium 2 oxygens in reality the compound always has slightly less than 2 oxygens; the surface is peppered with defects, gaps where an oxygen atom should be and the degree of imperfection varies.

For cerocene, the Nature source reads Another fun aspect of element 58 engendered by its redox activity is the somewhat unconventional and controversial electronic structures of its compounds, such as cerocene (Ce(C8H8)2), an 8-fold symmetric, eclipsed sandwich complex. The most accurate picture of the valence at its cerium cation has remained somewhat ambiguous. Energy decomposition analysis suggests a strong ionic interaction between the cerium centre and each cyclooctatetraene ring, and X-ray absorption spectroscopy indicates that cerocene has a ground state that is strongly multiconfigurational — so much so that the compound is now described as 'intermediate valent'. It is trapped between configurations of Ce(III) and Ce(IV) character that are quantum-mechanically admixed and comprise a strongly stabilized open-shell singlet ground state. ... The simultaneous local/non-local character of the 4f-electron in cerocene is reminiscent of f-element superconductors' behaviour, and investigations on cerium compounds can provide insight on how local behaviour gives rise to exotic materials properties. I'd do the same for the last source about the intermetallics, but I'd have to quote quite a lot of it.

In fairness, I cannot find where Kotani originally wrote that. However, I somehow doubt the Royal Society of Chemistry would've made it completely up. Double sharp (talk) 22:00, 23 January 2022 (UTC)

@Jo-Jo Eumerus: Double sharp (talk) 22:13, 23 January 2022 (UTC)

@Double sharp:Thanks for solving this; the problem with using audio sources is that they are harder to use. I am not sure that I would interpret the sources as implying Furthermore, each cerium atom in ceria does not lose all four of its valence electrons, but retains a partial hold on the last one, resulting in an oxidation state between +3 and +4, however; as far as I know a non stoichiometric compound is a different thing from "partial hold" and -ocene compounds to my understanding often have charge-valence peculiarities.

Incidentally, even after solving this issue I see there are other uncited sentences, stubby paragraphs and unsourced paragraphs here. Perhaps this should be sent to a good article review. Jo-Jo Eumerus (talk) 10:21, 24 January 2022 (UTC)

@Jo-Jo Eumerus: That bit is in the RSC podcast too: But if you take an even closer look at Ceria it becomes more confusing. At first sight it looks like a no-brainer. Cerium looses 4 electrons handing them over to the surrounding oxygen leaving aside defects, this means it has a 4+ oxidation state. But on very close inspection with x-ray spectroscopy its clear that the cerium hangs on to at least some of those four electrons and its true oxidation state is in a quantum mechanical limbo some where between 3 and 4.

I admit I haven't really kept a close eye on this article since I pushed it to GA in 2016; if you feel it should be sent to GAR, please feel free to do so. :) I see that most of the cn tags are for stuff about applications and biology; unfortunately the sources I have access to at the moment are mostly on chemistry, so I may not be able to fix them, but I can try looking. Double sharp (talk) 11:47, 24 January 2022 (UTC)

OK, I'll proceed. Jo-Jo Eumerus (talk) 16:37, 24 January 2022 (UTC)

References

GA Reassessment

This discussion is transcluded from Talk:Cerium/GA2. The edit link for this section can be used to add comments to the reassessment.

The article has several uncited sentences, stubby paragraphs and unsourced paragraphs and thus doesn't really reflect the WP:GA criteria. There are also some broken citations. Jo-Jo Eumerus (talk) 16:39, 24 January 2022 (UTC)

Seems like nothing happened since then. I'll delist this. Jo-Jo Eumerus (talk) 18:37, 2 February 2022 (UTC)

Omission of use of cerium in grinding optics

The article appears to omit the widespread use of cerium oxide as a polishing agent for the manufacture of accurate lenses and mirrors. A suspension of cerium oxide particles is used instead of much harder silicon carbide or even harder diamond grains on the surface of a tool made with polishing pitch, especially in hand polishing, because you want a hardness closer to the softness of the glass surface being polished, to avoid the over-removal of glass from the surface being polished. David Spector (talk) 19:48, 12 November 2022 (UTC)

GA Review

This review is transcluded from Talk:Cerium/GA3. The edit link for this section can be used to add comments to the review.

Reviewer: Szmenderowiecki (talk · contribs) 16:20, 1 August 2023 (UTC)

Note. The nominator has withdrawn from the GA assessment, so I had no choice but to ✗ Fail this nomination. Anyone with significant contributions to this article may restart the review from the place where it ended. Szmenderowiecki (talk) 02:45, 19 August 2023 (UTC)

Rate	Attribute	Review Comment
1. Well-written:
	1a. the prose is clear, concise, and understandable to an appropriately broad audience; spelling and grammar are correct.	No questions wrt spelling and grammar, but the text needs to be a bit less technical as we are writing for the general audience. For example, there are a lot of unfamiliar signs on the phase diagram (cF4, cI2, oC4 etc.) which need explanation (just like the α prime and α bis forms of cerium at high pressures and relatively low temperatures); in Cerium (IV) complexes, bidentate might need explanation. Make other such changes as you may see fit. Will do later. 141Pr {contribs} 14:36, 4 August 2023 (UTC) Cerium nitrates also form 4:3 and 1:1 complexes with 18-crown-6 (the ratio referring to that between cerium and the crown ether). -> you mean nitrate instead of cerium?  Done 141Pr {contribs} 14:36, 4 August 2023 (UTC) Cerium was the first of the lanthanides to be discovered, in Bastnäs, Sweden, by Jöns Jakob Berzelius and Wilhelm Hisinger in 1803, and independently by Martin Heinrich Klaproth in Germany in the same year. - I think it would be better to split the sentence in two - first about the early discovery of cerium; the other about the people who discovered it.  Done 141Pr {contribs} 14:36, 4 August 2023 (UTC)
	1b. it complies with the Manual of Style guidelines for lead sections, layout, words to watch, fiction, and list incorporation.	In extreme cases, cerium(IV) can form its own minerals separated from the other rare-earth elements, such as cerianite (Ce,Th)O 2(correctly named cerianite-(Ce)). - too many refs, too weirdly placed refs... Otherwise seems pretty OK I have amended that bit, hopefully it looks a bit less misplaced. 141Pr {contribs} 14:36, 4 August 2023 (UTC)
2. Verifiable with no original research:
	2a. it contains a list of all references (sources of information), presented in accordance with the layout style guideline.	For infobox cerium, if possible, I would format the first two refs (atomic weight and ionisation energies) to be consistent with the rest of the article; also, it is strange that you are using two different editions of CRC Handbook of Chemistry and Physics, one of which is patently out-of-date and the other probably so. There is easy access on the internet to the 97th ed (2016) (Template:RubberBible97th) or you can grab a newer one at a good scientific library, particularly since you declare to be living in the UK. If you need to cite the data, I think it would be better to do so to as newer the compilations of data as possible. I can help you out with the access if you need it. You may also want to consult the newer Holleman and Wiberg edition (103 ed., 2017), to which you may have access via the Wikipedia Library (De Gruyter), but this one is only in German. I'll try. 141Pr {contribs} 14:36, 4 August 2023 (UTC) I refer to oldid 1168714074 for my analysis of refs. NUBASE2016 can be easily updated to NUBASE2020, as is already the case in the infobox. Refs 13, 45, 48, 60 and 65 need more data to be filled in. Ref 52 would benefit from pointing the page where the info is located and you should probably merge it with ref 57; Ref 53 needs additional data (ISBN 0-87171-644-5). Merge refs 66 and 70. Remove ref 50 as it only gets you to the general page of mindat.org. If you want to retain ref 51, change it to http://cnmnc.units.it and find the relevant information supporting the sentence about cerianite. Still, I don't see the point of retaining it because there are already so many refs there. You can probably find some better ones as well if you want. I don't get why the article "Rare Earth Elements Recovery from Waste Fluorescent Lamps: A Review" is in an invisible comment - either cite it somewhere if relevant or remove it.
	2b. reliable sources are cited inline. All content that could reasonably be challenged, except for plot summaries and that which summarizes cited content elsewhere in the article, must be cited no later than the end of the paragraph (or line if the content is not in prose).	I noted all places which I believe should be cited with citation needed tags (just a couple of passages). The quality of sources is good, so this is almost a pass.
	2c. it contains no original research.	Once the cn tags are replaced with refs, or the relevant text is removed, it will be a pass.
	2d. it contains no copyright violations or plagiarism.	The article doesn't appear to have such issues.
3. Broad in its coverage:
	3a. it addresses the main aspects of the topic.	Well, this is something I have most questions about. There are some elements (like history) which are reasonably broadly covered (probably even to the degree of it being comprehensive), but some stuff IMHO is lacking. I compared to what is supposed to be the gold standard of our articles, namely caesium, niobium and yttrium (the latter is the closest we have to cerium), and I know we are at the GA not FA stage, but we should strive for FA at the end of the day, right? I won't be an asshole if you just write one or two sentences instead of whole paragraphs (that's GA, after all), but I will definitely be happy with comprehensive descriptions. Basically I'd expect as a reader to get the following info from an encyclopedia describing a chemical element: (cf. Britannica entry for cerium) What is the pure and commercially sold form of element, and why does commercial-grade element differ from purest form, if it does? Status: we only describe the pure form. How do we prepare the commercial-grade cerium we can buy from merchants (or maybe it's not that important as CeO2, for example)? Status: we have procedures describing how to get to CeO2, so we should make it clear that the pure metal is probably not as important. Because unlike gold, it's a metal which doesn't really exist alone in the earth's crust: how does it get mined, which minerals generally get mined in the world if a company wants to profit from cerium extraction (or maybe it's only separated from remnants of other minerals, is retrieved from waste, or maybe cerium alone isn't attractive enough and they extract the whole palette of rare earths, as it appears to be the case...?), how much of that do we mine and where are the principal areas where cerium minerals get extracted, and, if in a different place, purified? Also, it would be good if we knew more or less the breakdown of where cerium goes (how much goes to steel, how much to catalytic converters etc.) Status: we have a historical desription of how cerium got discovered and the principal minerals from which we extract cerium, but nothing more. We don't need to be too detailed, because some of the info is already available in the mineral articles, but I think we have to mention it. Maybe there's a stock exchange trading cerium, like there is for copper, lead or other metals? If so, how much does it cost per tonne? (A minor question, so I won't be upset if there is nothing you can find.) What compounds does it create and how does it react? Well, we have just about enough info for that, though adding a sentence or two won't hurt. Maybe there are some alloys that it can create and are commercially useful? I saw a lot of technical information in this quite old publication, but it says little of what is useful in industry. There is some info in the article already, in the section "Applications", but let me know if you find anything more. Where is it used? You may want to see if there are any more applications than those already mentioned. Niche uses may be easily placed within "other uses" category. Hazardous/biological role? This section is generally fine, but the sentence about the bacterium needing cerium as a cofactor for its proteins is unnecessarily mentioned twice. How it got discovered? This section is pretty fine as well, but it only stops at the stage of purifying ceria (CeO2), and we also need pure Ce metal. There has been a lot of literature published on rare earths lately and probably on cerium specifically, at least as it appears from the internet query into pdfs of books I made yesterday. I can help you with finding sources and also will suggest a couple to include a bit later, both from these and from Google Scholar.
	3b. it stays focused on the topic without going into unnecessary detail (see summary style).	The size is OK. There are a couple of topics I think we need to add/expand, but unless you are going to expand the article x3 or so, it should be OK. The article stays focused on the topic.
	4. Neutral: it represents viewpoints fairly and without editorial bias, giving due weight to each.	No problems with that.
	5. Stable: it does not change significantly from day to day because of an ongoing edit war or content dispute.	No problems with that, either.
6. Illustrated, if possible, by media such as images, video, or audio:
	6a. media are tagged with their copyright statuses, and valid non-free use rationales are provided for non-free content.	Generally OK. The image in the infobox uses CC 3.0 Unported license, not 1.0 license as provided - a minor detail that may need change. File:Cerium phase diagram.jpg will definitely benefit from converting to svg, if you know how to do just that - it will also be good if you provided info about the critical temperature and junctions in the phase diagram, if you can find this info in the literature.
	6b. media are relevant to the topic, and have suitable captions.	Add alt captions to each image whenever appropriate (accessibility).  Done 141Pr {contribs} 08:50, 12 August 2023 (UTC) Yeah, I corrected the alt descriptions somewhat but that's a pass. Szmenderowiecki (talk) 15:03, 12 August 2023 (UTC)
	7. Overall assessment.

BTW, I have another GA review to finish, so I might not spend much time on this for now. ¹⁴¹Pr {contribs} 14:39, 4 August 2023 (UTC)

Take your time, and keep up your work on holmium. I also don't have much time lately, but you will see my remarks when I'm ready. Szmenderowiecki (talk) 19:35, 4 August 2023 (UTC)

Praseodymium-141, my review is ready. I put this GA nomination on hold pending improvements to the article. Because you are busy with other reviews, don't rush here yet, I'd just ask you to go through the review in a reasonable time, when you are done with your other duties. I have proposed some articles and books that may further enhance the article, and it would be a big bonus if you incorporated the material I compiled. Some of these articles may improve other rare earth metal entries, so you may want to use them there as well. Obviously, if you want to make your own research and find a couple of scholarly works I didn't mention, go ahead and do so. Szmenderowiecki (talk) 14:05, 5 August 2023 (UTC)

@Szmenderowiecki: I'm very busy in real life, is it ok if I pass this reivew to other WP:ELEM editors? I've already requested in the project talk page. ¹⁴¹Pr {contribs} 10:10, 17 August 2023 (UTC)

Yeah, I'll make the formal steps for that in a couple of hours. Szmenderowiecki (talk) 19:29, 17 August 2023 (UTC)

Sorry about that. I'm too busy in real life. You review was great. (keep this up!) 😅 ¹⁴¹Pr {contribs} 16:18, 18 August 2023 (UTC)

Sources for consideration

Journals

• Czerwinski, Frank (2020-01-01). "Cerium in aluminum alloys". Journal of Materials Science. 55 (1): 24–72. doi:10.1007/s10853-019-03892-z. ISSN 1573-4803. - brilliant intro
• Gao, Ying; Gao, Fei; Chen, Kan; Ma, Jin-lu (2014-05). "Cerium oxide nanoparticles in cancer". OncoTargets and Therapy: 835. doi:10.2147/OTT.S62057. ISSN 1178-6930. PMC 4043807. PMID 24920925. {{cite journal}}: Check date values in: |date= (help)CS1 maint: PMC format (link) CS1 maint: unflagged free DOI (link)
• Rajeshkumar, S.; Naik, Poonam (2018-03-01). "Synthesis and biomedical applications of Cerium oxide nanoparticles – A Review". Biotechnology Reports. 17: 1–5. doi:10.1016/j.btre.2017.11.008. ISSN 2215-017X.
• Cassee, Flemming R.; van Balen, Erna C.; Singh, Charanjeet; Green, David; Muijser, Hans; Weinstein, Jason; Dreher, Kevin (2011-03). "Exposure, Health and Ecological Effects Review of Engineered Nanoscale Cerium and Cerium Oxide Associated with its Use as a Fuel Additive". Critical Reviews in Toxicology. 41 (3): 213–229. doi:10.3109/10408444.2010.529105. ISSN 1040-8444. {{cite journal}}: Check date values in: |date= (help) - should be available on Wikipedia Library.
• Zhang, Mengzhen; Zhang, Chao; Zhai, Xinyun; Luo, Feng; Du, Yaping; Yan, Chunhua (2019-11-01). "Antibacterial mechanism and activity of cerium oxide nanoparticles" (PDF). Science China Materials. 62 (11): 1727–1739. doi:10.1007/s40843-019-9471-7. ISSN 2199-4501.
• Feng, Na; Liu, Ying; Dai, Xianglin; Wang, Yingying; Guo, Qiong; Li, Qing (2022). "Advanced applications of cerium oxide based nanozymes in cancer". RSC Advances. 12 (3): 1486–1493. doi:10.1039/D1RA05407D.
• Allahkarami, Ebrahim; Rezai, Bahram (2021-02-01). "A literature review of cerium recovery from different aqueous solutions". Journal of Environmental Chemical Engineering. 9 (1): 104956. doi:10.1016/j.jece.2020.104956. ISSN 2213-3437. - should be available on Wikipedia Library
• Binnemans, Koen; Jones, Peter Tom; Blanpain, Bart; Van Gerven, Tom; Yang, Yongxiang; Walton, Allan; Buchert, Matthias (2013-07). "Recycling of rare earths: a critical review". Journal of Cleaner Production. 51: 1–22. doi:10.1016/j.jclepro.2012.12.037. {{cite journal}}: Check date values in: |date= (help) - mostly about rare earths rather than Ce specifically, but you can add a sentence or two about efforts to recycle Ce (or lack thereof)
• Montini, Tiziano; Melchionna, Michele; Monai, Matteo; Fornasiero, Paolo (2016-05-25). "Fundamentals and Catalytic Applications of CeO 2 -Based Materials". Chemical Reviews. 116 (10): 5987–6041. doi:10.1021/acs.chemrev.5b00603. ISSN 0009-2665. - cerium-based materials used in catalysts in cars
• Royal Society of Chemistry - how they made pure cerium
• Tyler, Germund (2004-12-01). "Rare earth elements in soil and plant systems - A review". Plant and Soil. 267 (1): 191–206. doi:10.1007/s11104-005-4888-2. ISSN 1573-5036. - absorption of rare earths, including cerium, by plants

In medical fields, I tried to select review articles, but still pay particular attention to WP:MEDRS (not that the article currently violates it).

Praseodymium-141 Re this removal, I think any of the three sources could cover it well: [1] [2] [3]. The Jakupec book should cover the part about bones. Szmenderowiecki (talk) 04:37, 11 August 2023 (UTC)

Ok, I have readded the part and referenced it. ¹⁴¹Pr {contribs} 09:24, 12 August 2023 (UTC)

Books

• Kilbourn, Barry T. (2011-07-15), John Wiley & Sons, Inc. (ed.), "Cerium and Cerium Compounds", Kirk-Othmer Encyclopedia of Chemical Technology, Hoboken, NJ, USA: John Wiley & Sons, Inc., doi:10.1002/0471238961.0305180911091202.a01.pub3, ISBN 978-0-471-23896-6, retrieved 2023-08-05 - available via the Wikipedia library, good example of what the Wikipedia article could look like

The wikilibrary doesn't seem to have this book. Where do I find it? ¹⁴¹Pr {contribs} 16:20, 13 August 2023 (UTC)

Try this link. If you still cant access it, I'll send it to you by email. Szmenderowiecki (talk) 20:19, 13 August 2023 (UTC)

• Jakupec, M. A.; Unfried, P.; Keppler, B. K. (2005). Pharmacological properties of cerium compunds. Vol. 153. Berlin, Heidelberg: Springer Berlin Heidelberg. pp. 101–111. doi:10.1007/s10254-004-0024-6. ISBN 978-3-540-24012-9. Retrieved 2023-08-05. {{cite book}}: |work= ignored (help) - more about cerium in medical applications
• Scirè, Salvatore; Palmisano, Leonardo, eds. (2020). Cerium Oxide (CeO2): synthesis, properties and applications. Metal oxides series. Amsterdam Oxford Cambridge: Elsevier. ISBN 978-0-12-815661-2. - a whole book dedicated to cerium and cerium oxide, but not available at all on the internet (neither my uni nor Wikimedia give access)
• Basu, Basudeb; Banerjee, Bubun, eds. (2023-05-04). Rare Earth Elements. De Gruyter. ISBN 978-3-11-078808-2. - a couple of chapters in the end dedicated to cerium compounds, e.g. CAN. Available through the Wikipedia Library.
• Spellman, Frank R. (2023). The science of rare earth elements: concepts and applications (First edition ed.). Boca Raton London New York: CRC Press. ISBN 978-1-003-35081-1. {{cite book}}: |edition= has extra text (help) - this one has a safety profile and handling instructions on pp. 104-106; there is also a moderately useful image of rare earth metals being used in car manufacturing.
• Pöttgen, Rainer; Jüstel, Thomas; Strassert, Cristian A. (2020). Rare earth chemistry. De Gruyter STEM. Berlin Boston: De Gruyter. ISBN 978-3-11-065360-1. - they have a very good history introduction, otherwise may br worth reading for your other articles. Available through the Wikipedia Library.

Source verification: Greenwood and Earnshaw (1997). Chemistry of the Elements (2nd ed.)

Does anyone have access to the Greenwood and Earnshaw ref? I would like to verify:

• "Cerium is the most abundant of all the lanthanides, "
• "Thus, despite its position as one of the so-called rare-earth metals, cerium is actually not rare at all."
• any comparison of abundance to the abundance of other elements similar to the one in the article.

The measured abundances of less common elements varies widely with the location tested. Consequently comparisons of "relative abundance" are often meaningless. Nevertheless wikipedia editors like to read the tables of abundance and draw their own conclusions.

Tnanks! Johnjbarton (talk) 15:55, 14 April 2024 (UTC)

Sure! According to G&E pg. 1229,

Apart from the unstable ¹⁴⁷Pm (half-life 2.623 y) of which traces occur in uranium ores, the lanthanides are actually not rare. Cerium (66 ppm in the earth's crust) is the twenty-sixth most abundant of all elements, being half as abundant as Cl and 5 times as abundant as Pb. Even Tm (O.5 ppm), the rarest after Pm, is rather more abundant in the earth's crust than is iodine.

So, I guess it answers the second and third bullet points and indirectly the first (I guess?). ¹⁴¹Pr {contribs} 16:09, 14 April 2024 (UTC)