What is this Chemical?

Quote: Originally posted by woelen

Most likely the green stuff is not Cr2(SO4)3.xH2O, but a basic chromium sulfate. Basic chromium sulfate is green and its solutions also are green. When a small amount of H2SO4 or HNO3 is added and allowed to stand for a few days, then the solution turns purplish/grey. Basic chromium sulfate is present on eBay: http://www.ebay.nl/itm/1kg-Chromium-Sulphate-top-quality-/22... The formula on the bottle is wrong. In reality it best can be written as: [Cr(OH)2]Cr(SO4)2 or as [Cr(OH)]2(SO4)2 or simply [Cr(OH)]SO4 It also sometimes is written as: [CrO]Cr(SO4)2.H2O Solotions of this compound contain the green [Cr(OH)](2+) ion, the green [Cr(OH)2](+) ion and green sulfato-chromium(III) complexes. The commercial product usually contains one sodium ion besides each chromium ion (due to how it is made) and then the net formula is [Cr(OH)2]Cr(SO4)2.Na2SO4 or [Cr(OH)]2(SO4)2.Na2SO4 Also written as: [CrO]Cr(SO4)2.Na2SO4.H2O Separation from the sodium sulfate is difficult and for its application it does not really matter, so the commercial product nearly always is the one with the sodium sulfate in it.

Quote: Originally posted by The Volatile Chemist

With regards to the magnesium sulfate, you could always give it to a school or something, they always have use for the stuff in high schools. And if the compound of the year for the US Crystal growing competition is magnesium sulfate, well there you go...