Chromium(III) sulfate

Chromium(III) sulfate
Names
	IUPAC name Chromium(III) sulfate
	Other names Basic chromium sulfate, chromic sulfate
Identifiers
CAS Number	10101-53-8 ;
3D model (JSmol)	Interactive image;
ChemSpider	19951509 ;
ECHA InfoCard	100.030.217
PubChem CID	24930;
UNII	Y0C99N5TMZ ;
CompTox Dashboard (EPA)	DTXSID20890642 ;
	InChI InChI=1S/2Cr.3H2O4S/c;;31-5(2,3)4/h;;3(H2,1,2,3,4)/q2+2;;;/p-6 Key: LPRGTYRWAKBNSY-UHFFFAOYSA-H ; InChI=1/2Cr.3H2O4S/c;;31-5(2,3)4/h;;3(H2,1,2,3,4)/q2+2;;;/p-6 Key: LPRGTYRWAKBNSY-CYFPFDDLAG;
	SMILES [Cr+2].[Cr+2].[O-]S(=O)(=O)[O-].[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O;
Properties
Chemical formula	H24Cr2S3O24
Molar mass	392.16 g/mol ; 716.45 g/mol (octadecahydrate)
Appearance	reddish-brown crystals (anhydrous), purple crystals (hydrated)
Density	3.10 g/cm3 (anhydrous) ; 1.86 g/cm3 (pentadecahydrate) ; 1.709 g/cm3 (octadecahydrate)
Melting point	90 °C
Boiling point	decomposes to chromic acid
Solubility in water	insoluble (anhydrous) ; soluble (hydrated)
Solubility	soluble in alcohol ; practically insoluble in acid
Hazards
NFPA 704 (fire diamond)	1 0 0
Flash point	Non-flammable
	Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). verify (what is ?) Infobox references

Chromium(III) sulfate usually refers to the inorganic compound with the formula Cr₂(SO₄)₃ • 12(H₂O). This consists of the hydrated sulfate salt of the metal aquo complex with the formula [Cr(H₂O)₆]³⁺, which is responsible for the purple color of this salt. It is widely used in the tanning of leather, with associated environmental damage.^{[citation needed]}

Properties

Heating chromium(III) sulfate leads to partial dehydration to give a hydrated green salt (CAS#10031-37-5) and eventually the anhydrous derivative (CAS#10101-53-8).

Production

Basic chromium sulfate is produced from chromate salts by reduction with sulfur dioxide, although other methods exist.^[1] The hydrous form may be formed by the reaction of chromium(III) oxide and sulfuric acid.

Cr₂O₃ + 3 H₂SO₄ → Cr₂(SO₄)₃ + 3 H₂O

References

^ Gerd Anger, Jost Halstenberg, Klaus Hochgeschwender, Christoph Scherhag, Ulrich Korallus, Herbert Knopf, Peter Schmidt, Manfred Ohlinger. "Chromium Compounds". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.a07_067. ISBN 978-3527306732.{{cite encyclopedia}}: CS1 maint: multiple names: authors list (link)

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[Ullmann-1] Gerd Anger, Jost Halstenberg, Klaus Hochgeschwender, Christoph Scherhag, Ulrich Korallus, Herbert Knopf, Peter Schmidt, Manfred Ohlinger. "Chromium Compounds". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.a07_067. ISBN 978-3527306732.{{cite encyclopedia}}: CS1 maint: multiple names: authors list (link)

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