Chromium(II) sulfate

{{Chembox

| ImageFile = Chromium II sulfate pentahydrate.jpg

| ImageCaption = Crystalline sample wet with ethanol

| ImageFile1 = CuSO4 (5aq).jpg

| ImageCaption1 = Structure of chromium(II) sulfate pentahydrate ({{chem2|CrSO4*5H2O}}){{legend|rgb(256, 92, 0)|Chromium, Cr}}{{legend|yellow|Sulfur, S}}{{legend|red|Oxygen, O}}{{legend|white|Hydrogen, H}}

| IUPACName = Chromium(2+) sulfate

| OtherNames = chromous sulfate, chromous sulphate

| Section1 = {{Chembox Identifiers

| CASNo = 13825-86-0

| CASNo_Comment = (anhydrous)

| CASNo2 = 15928-77-5

| CASNo2_Comment = (pentahydrate)

| CASNo3 = 19512-13-1

| CASNo3_Comment = (trihydrate)

| UNII_Ref = {{fdacite|correct|FDA}}

| UNII = Y0C99N5TMZ

| UNII_Comment = (anhydrous)

| UNII2_Ref = {{fdacite|correct|FDA}}

| UNII2 = 990MUV05EC

| UNII2_Comment = (pentahydrate)

| PubChem = 61686

| PubChem_Comment = (anhydrous)

| ChemSpiderID = 55589

| ChemSpiderID_Comment = (anhydrous)

| SMILES = [Cr+2].[O-]S(=O)(=O)[O-]

| SMILES_Comment = anhydrous

| SMILES1 = [OH2+][Cr-3]([OH2+])([OH2+])([OH2+])O(S(=O)(=O)[O-]).O

| SMILES1_Comment = pentahydrate

| InChI =

| InChIKey = RYPRIXSYXLDSOA-NUQVWONBAQ

| StdInChI =

| StdInChIKey = RYPRIXSYXLDSOA-UHFFFAOYSA-L

}}

| Section2 = {{Chembox Properties

| Formula = {{chem2|CrSO4}} (anhydrous)
{{chem2|CrSO4*5H2O}} (pentahydrate)

| MolarMass = 148.05 g/mol (anhydrous)
238.13 g/mol (pentahydrate)

| Appearance = Blue crystalline solid (pentahydrate)

| Density =

| MeltingPt =

| BoilingPt =

| Solubility = 21 g/(100 mL) (0°C, pentahydrate)

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| Section3 = {{Chembox Hazards

| MainHazards =

| FlashPt =

| AutoignitionPt =

}}

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Chromium(II) sulfate is an inorganic compound with the chemical formula {{chem2|CrSO4|auto=1}}. It often comes as hydrates {{chem2|CrSO4*nH2O}}. Several hydrated salts are known. The pentahydrate {{chem2|CrSO4*5H2O}} is a blue solid that dissolves readily in water. Solutions of chromium(II) are easily oxidized by air to Cr(III) species. Solutions of Cr(II) are used as specialized reducing agents of value in organic synthesis.A. Zurqiyah and C. E. Castro "Reduction of Conjugated Alkenes With Chromium(II) Sulfate: Diethyl Succinate" Organic Syntheses, Vol. 49, p.98 (1969).{{doi|10.15227/orgsyn.049.0098}}

The salt is produced by treating chromium metal with aqueous sulfuric acid:Handbook of Preparative Inorganic Chemistry, 2nd Ed. Edited by G. Brauer, Academic Press, 1963, NY. Vol. 2. p. 1365.

:{{chem2|Cr + H2SO4 + 5 H2O → CrSO4*5H2O + H2}}

It can be produced through the reaction of sulfate salts and chromium(II) acetate{{Greenwood&Earnshaw}} or, for in situ use, the reduction of chromium(III) sulfate with zinc.