Talk:Neptunium

Image

There used to be an image of a neptunium sphere. Now it’s got replaced by liquified neptunium. Why is this? Legoplanecrash5383 (talk) 22:21, 3 August 2024 (UTC)

Because: "Changed infobox image because the previous image was a nickel-clad sphere, we weren't seeing actual neptunium metal". –LaundryPizza03 (dc̄) 00:44, 4 August 2024 (UTC)

It's not liquefied neptunium, it's solid. Source: HertzDonuts (talk) 05:57, 4 August 2024 (UTC)

@HertzDonuts: Though, this site claims that the Np image is not real. (Though it includes a real one, with a long-since dead source.) Double sharp (talk) 15:05, 20 August 2024 (UTC)

If that Np is fake, it should be deleted, just like other fake element pictures. But after that we have no more pictures of Np left except the original nickel-clad sphere. Nucleus hydro elemon (talk) 15:29, 20 August 2024 (UTC)

@Nucleus hydro elemon: There is a real Np pic here. Double sharp (talk) 16:12, 20 August 2024 (UTC)

That image appears to have been created during the research for paper which has been published under a CC license, but the image wasn't part of the paper and is copyright a japanese nuclear institute, so we can't use it. Mrfoogles (talk) 17:53, 20 August 2024 (UTC)

We could under fair use if it's really true that there's no free equivalent. We already do that for curium, after all. Double sharp (talk) 03:25, 21 August 2024 (UTC)

I've uploaded that picture of neptunium. Nucleus hydro elemon (talk) 10:43, 3 September 2024 (UTC)

Thank you! Double sharp (talk) 10:44, 3 September 2024 (UTC)

This website claims that it's a photo of caesium. Mrfoogles (talk) 17:41, 20 August 2024 (UTC)

It can't possibly be that: caesium is golden. Double sharp (talk) 03:32, 21 August 2024 (UTC)

Also, the Np image is by LLNL, which is a US Government contracter, and its employees are not employees of the federal government, so I think that the license is incorrect. I'm pretty sure that LLNL publishes its images under a CC-BY-NC license. Mrfoogles (talk) 17:47, 20 August 2024 (UTC)

I've removed the picture, due to concerns (see above) over whether it's real or not. Double sharp (talk) 15:37, 2 September 2024 (UTC)

There is a picture of a neptunium fragment in a Japanese lab. Why does the image keep frequently changing? 2603:8080:D03:89D4:4CEA:FD5B:6E65:90A (talk) 02:18, 10 September 2024 (UTC)

Because we found out that the first picture didn't show visible Np (because it was nickel-plated), and then we found out that the second picture didn't show visible Np either (because it's a computer-generated imitation). So this seems to be the best we can do. Double sharp (talk) 02:22, 10 September 2024 (UTC)

I think I've found a real image of Neptunium metal that isn't copyrighted: https://www.flickr.com/photos/jsjgeology/54040270387/in/album-72177720320871189/

It comes from the same source as the Protactinium image ~2026-19883-06 (talk) 13:42, 31 March 2026 (UTC)

Change oxidation states in infobox

I propose the common oxidation states in the infobox be changed to +4, +5, and +6. Please read the discussion here.

UnbihexiumFan (talk | contribs) 18:19, 27 May 2026 (UTC)

Could you provide relevant sources? Keres🌕Luna ^edits! 02:52, 28 May 2026 (UTC)

: states that while +5 is the most common oxidation state in environmental conditions, but +4 and +6 are also found.

: states that structures of +4, +5, and +6 are more common whereas those of +3 and +7 are rare.

pp. 91–2: states that Np(VII) is unstable and reduces, slowly in highly basic media and quickly in acidic media

pp. 752–55: states that NpO2+2 is stable in acidic solution and that Np³⁺ is readily oxidized in ambient conditions

: states that Np³⁺ is readily oxidized in ambient conditions

UnbihexiumFan (talk | contribs) 02:58, 28 May 2026 (UTC)

Sorry I don't think these source establish your claim.

• Nilsson, K., & Carlsen, L. (1989). The migration chemistry of neptunium. Risø National Laboratory. Np(V) is the most common oxidation state of neptunium to expect in the environmental pH range under moderately oxidizing conditions
• Gilson, S. E., & Burns, P. C. (2021). The crystal and coordination chemistry of neptunium in all its oxidation states: An expanded structural hierarchy of neptunium compounds. Coordination Chemistry Reviews, 445, 213994. This source is about crystals only. It may be tempting to assume that an understanding of the crystal chemistry of uranium readily applies also to neptunium, but this is not the case, as the redox chemistry of Np is distinct, and the importance of the Np(V) oxidation state is the cause of major departures from the crystal chemistry of uranium.

The remainder are negative evidence.

It think your best bet (and not a sure one) is a textbook reviewing elemental chemistry. Johnjbarton (talk) 18:47, 28 May 2026 (UTC)

• Gilson and Burns: The majority of structures contain Np(V) (149), Np(VI) (99), or Np(IV) (91) whereas structures containing Np(II), Np(III), Np(VII), or more than one oxidation state are rare.
• Nilsson and Carlsen: Under environmental conditions neptunium should exist predominantly in oxidation state V in the form NpO+2 and to some extent also as Np(IV) in the form of Np⁴⁺ and Np(VI) in the form of NpO2+2. That +5 is the most common does not mean that other states aren't common as well.

As for more sources:

• : Neptunium is known to exist in a range of oxidation states ranging from +III to +VII, of which the +IV, V and VI states are the most common in aqueous conditions.

I linked the other sources as justification for not wanting to include +3 or +7 as common.

UnbihexiumFan (talk | contribs) 20:04, 28 May 2026 (UTC)

I don't think there is a strong enough argument for +4 or +6 here.

• Yoshida, Z., Johnson, S.G., Kimura, T., Krsul, J.R. (2010). Neptunium. In: Morss, L.R., Edelstein, N.M., Fuger, J. (eds) The Chemistry of the Actinide and Transactinide Elements. Springer, Dordrecht. says The pentavalent neptunium ion, which is the most stable oxidation state in solution...

I am seeing that there isn't really a consensus on the 'common' oxidation state other than +5, In this case, the common one should be just left as +5 IMO. Keres🌕Luna ^edits! 16:15, 3 June 2026 (UTC)

I don't see a contradiction or lack of consensus. The +5 state is universally agreed to be the most stable and common, but that doesn't mean that other oxidation states aren't stable or common. I think not listing anything other than +5 implies that these aren't stable or common, when sources seem to agree that despite them being less stable/common they are still stable/common. Again, not listing +4 as a common oxidation state seems to be contradictory with the article, which states The most stable state in solution is +5, but the valence +4 is preferred in solid neptunium compounds. Yoshida et al. in the same book (p. 766) say that NpO2+2 is predominant in strong acidic solution.

UnbihexiumFan (talk | contribs) 17:40, 3 June 2026 (UTC)

On neptunium oxides

The article says Three anhydrous neptunium oxides have been reported, NpO₂, Np₂O₅, and Np₃O₈, though some studies have stated that only the first two of these exist, suggesting that claims of Np₃O₈ are actually the result of mistaken analysis of Np₂O₅. However, as the full extent of the reactions that occur between neptunium and oxygen has yet to be researched, it is not certain which of these claims is accurate. However, says that the existence of Np₃O₈ has conclusively been disproven, and says that NpO₂ and Np₂O₅ are the only stable oxides.

UnbihexiumFan (talk | contribs) 02:44, 3 June 2026 (UTC)

When I wrote the chemistry section of this article, the articles you linked to hadn't been published. Feel free to update it, it's good to know that Np₃O₈ really is mythical. :D Double sharp (talk) 06:55, 3 June 2026 (UTC)

I would like to update it myself, but I'm not sure what the best way to do it is... I was hoping someone else would be able to reword that statement.

Side note: "mythical" is a great way to describe a chemical compound

UnbihexiumFan (talk | contribs) 17:41, 3 June 2026 (UTC)

I have updated statements of Np₃O₈ and Np₄O₉. Nucleus hydro elemon (talk) 06:37, 5 June 2026 (UTC)