Talk:Copper chromite

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Move to Copper chromite?[edit]

I am not a super expert but it appears that the Atkins catalyst is also known as copper chromite. The latter name seems more common, based on Org. Syn. This material is available with at least three CAS numbers.--Smokefoot 05:32, 5 May 2007 (UTC) This appears to be focused purely on a unique phase that is represented as Cu2Cr2O5. True copper chromite is of a different formula to that discussed on this page. Sandgk 16:54, 31 May 2007 (UTC)[reply]

The form used in hydrogenations is reduced to CuCrO2. TaylorLeem (talk) 23:36, 12 June 2020 (UTC)[reply]

preparation[edit]

Ba
₂Cu
₂(NH
₄)
₂(CrO
₄)
₅ → CrCuO3 + CuO + 2Ba + 4H
₂O + 4Cr + N
₂ + 6O
₂ i think there is a mistake, elementary barium and chromium with oxygen...? Morsagh (talk) 09:27, 7 August 2014 (UTC)[reply]

How come the 'other name' does not contain any copper?83.95.177.199 (talk) 09:47, 16 November 2018 (UTC)alexander.senning@gmail.com[reply]

The article needs substantial clean-up with respect to formulas stoichiometry relation to the spinel structure etc.150.227.15.253 (talk) 13:49, 10 September 2019 (UTC)[reply]

Further points to look at. The formula is initially written as Cu2Cr2O5, but then as CuCrO3. The formation of chromium (II) oxide CrO, which is a sensitive and very easily oxidised compound, from heating of copper ammonium chromate also needs to be confirmed. 150.227.15.253 (talk) 12:36, 21 September 2020 (UTC)[reply]

Wrong picture[edit]

Picture shows Spinel MgAl2O4 crystal structure but this compound is Cu2Cr2O5 which does not match the pattern for that xtal structure. TaylorLeem (talk) 23:33, 12 June 2020 (UTC)[reply]

The statement that copper chromite crystallizes in the spinel group deserves some further comments and explanations in the text. What I write here is my interpretation of situation. If someone can confirm it please adjust the article text accordingly. The name copper chromite and spinel structure suggest that the formula would be CuCr2O4 in analogy with the minerals chromite FeCr2O4 and magnesiochromite MgCr2O4 in the spinel group. In that case the igninition of copper chromate should also yield CuO- However, presuming that the formula CuCrO3 (Cu(II)Cr(IV)O3 or possibly Cu(III)Cr(III)O3) is correct one must conclude that it crystallizes with cation vacancies in order to make it compatible with the spinel structure, cf gamma-Fe2O3 maghemite which crystallizes in a spinel structure with vacancies. However in the maghemite case divalent ions are absent. Can there be vacancies for higher valent ions or can the copper enter positions normally held by trivalent ions? (This is probably not self-evident, even if the copper is trivalent it could be too large for those positions.) 150.227.15.253 (talk) 12:18, 21 September 2020 (UTC)[reply]

With the formula Cu2Cr2O5 (Cu(II)2Cr(III)2O5) one would need to assume both trivalent vacancies and oxygen vacacies to make it compatible with the spinel structure. Oxide structures are often based on rather dense packing of oxide ions. Wouldn't such structures be sensitive to large (stoichiometric) amounts of oxide ion vacancies collapsing into something else?150.227.15.253 (talk) 12:29, 21 September 2020 (UTC)[reply]

Please remove the non-sensical formulas.[edit]

In what universe does a reaction generate free oxygen and barium metal at the same time? In Wikipedia Outer Limits ... TaylorLeem (talk) 00:06, 13 June 2020 (UTC)[reply]

@TaylorLeem: Oh you didnt know? The universe you are referring to is called Wikipedia. In the chemistry area, it is constructed by dedicated, hard working, imperfect, assiduous editors that respond to critics like you who contribute nothing. Get back to us after your 10,000th edit, then we can talk. Or go back to FoxNews.--Smokefoot (talk) 02:59, 13 June 2020 (UTC)[reply]