Talk:Nickel chromate

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Appearance[edit]

I doubt about the appearance of the sample shown in the photo and that listed in the ChemBox. According to CRC Handbook of Chemistry and Physics, P.4-78, Section "Physical constants of Inorganic Compounds", the description for the compound is "Red solid". The powder in the photo doesn't look red at all, but somewhat brown, which may indicate the presence of a large amount of impurities. LHcheM (talk) 08:12, 26 March 2012 (UTC)

No original research[edit]

The edit summary for the creation of this article (1 Feb. 2008) reads: "I had to isolate Nickel Chromate as a chem lab and had a lot of trouble finding information on it. We performed a series of tests on the nickel chromte we isolated and decided to put our findings on w"

Sorry, but this is clearly in violation of the No Original Research policy - see WP:NOR. Subsequent edits are very minor and provide no references to external sources as required. If this is not remedied, the article will have to be deleted.

Yes, it is hard to find info on NiCrO4; I found nothing in several inorganic texts (Cotton and Wilkinson, Huheey, Jolly, Miessner and Tarr) or in the Handbook of Chemistry and Physics. If this article is to stay in Wiki, someone will have to do the work of finding info from verifiable sources - try Chemical Abstracts to start. Or perhaps go through all the Google references, most of which look irrelevant.

It would also be of interest to explain why this compound is of interest, and to provide more quantitative information. Dirac66 (talk) 03:56, 5 March 2008 (UTC)

It would be good to put a notice on the page if it is original research. Only it helped me in my home lab when I was analyzing the properties of the dissolution of Nichrome. --Chemicalinterest (talk) 11:49, 10 May 2010 (UTC)

Possibly flawed article[edit]

Although I am sure the article was created with the best of intentions, there are reasons to think that it is flawed. Nickel chromate seems usually to be a mistaken term of nickel chromite. The CAS #12018-18-7 corresponds to NiCr2O4, a spinel that has been well studied. I would expected that NiCrO4, like the sulfate, is real but I cannot find a thing on nickel(II) chromate in CAS or the inorganic pigment literature. So I was going to strongly revise this article and redirect it to the chromite.--Smokefoot (talk) 15:49, 31 March 2012 (UTC)

The Inorganic Crystal Structure Database has two entries for NiCrO4 (same structure, both published 1969, R-factors both about 0.11). So it does seem to exist. Both reports are published in journals I don't have access to (Zeitschrift für Kristallographie, Kristallgeometrie, Kristallphysik, Kristallchemie and Bulletin de la Societe Francaise de Mineralogie et de Cristallographie), so I can't tell you how they made it. I can get the crystal structure data from the database if anyone wants it or wants a picture making. The structure is as you'd expect, a big fat 3D network with octahedral Ni and tetrahedral Cr.
There's not much on "nickel chromate" on Web of Knowledge, either. The earliest mention is from 1906! M. Gröger, Z. Anorg. Allg. Chem. (1906) 51, 348–355. Not an awful lot since. --Ben (talk) 19:23, 2 April 2012 (UTC)

Here's the reference for one the 1969 crystal structure determinations: O. Muller, W. B. White, R. Roy, Z. Kristallogr. (1969) 130, 112–120. --Ben (talk) 19:29, 2 April 2012 (UTC)

Well that is a coup of searching. Sometimes CAS is just useless. I never use to inorganic database as the interface here is not so slick, maybe I should try again. I am still thinking of moving this thing to the chromite derivative (that is what the CAS# is for) because that material seems to be more heavily studied. Ullmann's does not mention NiCrO4 for anything, when I was expecting it as a pigment. Thanks, --Smokefoot (talk) 19:52, 2 April 2012 (UTC)

We're lucky to have the Chemical Database Service, which has a web-based compendium of crystallographic databases for academics in the UK. You can search the CSD, the ICSD, CrystMet and a few other databases simultaneously. I'm suprised there isn't something even bigger and better in North America. There are 23 hits on the system for NiCr2O4, I've saved them here for you: http://www.benjamin-mills.com/Wikipedia/CrystalWebHitDisplayNiCr2O4.pdf. Seems that you're right to emphasise the better characterised, more important compound in the Ni-Cr-O system. We could keep a stub here, or make it a subsection or mention at Nickel chromite. --Ben (talk) 21:19, 2 April 2012 (UTC)