Chromium(II) sulfate

Chromium(II) sulfate
IUPAC name
Chromium(2+) sulfate
Other names
chromous sulfate, chromous sulphate
15928-77-5 (pentahydrate)
19512-13-1 (trihydrate)
13825-86-0 (anhydrous)
ChemSpider 55589
PubChem 61686
CrSO4·5 H2O
Molar mass 238.13 (pentahydrate)
Appearance blue solid (pentahydrate)
21 g/100 mL (0°C, pentahydrate)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references

Chromium(II) sulfate refers to inorganic compounds with the chemical formula CrSO4·n H2O. Several closely related hydrated salts are known. The pentahydrate 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.[1]

The salt is produced by treating chromium metal with aqueous sulfuric acid:[2]

Cr + H2SO4 + 5 H2O → CrSO4·5 H2O + H2

It can be produced through the reaction of sulfate salts and chromium(II) acetate[3] or, for in situ use, the reduction of chromium(III) sulfate with zinc.[1]


In aqueous solutions chromium(II) sulfate forms metal aquo complexes, presumably with six water ligands. The structures of the crystalline salts are similar to the corresponding hydrates of copper(II) sulfate: pentahydrate, trihydrate, monohydrate, and anhydrous derivatives of chromous sulfate are known. In all of these compounds, the Cr(II) centre adopts octahedral coordination geometry, being coordinated to six oxygen centers provided by a combination of water and sulfate ligands.[4][5]


  1. 1 2 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
  2. Handbook of Preparative Inorganic Chemistry, 2nd Ed. Edited by G. Brauer, Academic Press, 1963, NY. Vol. 2. p. 1365.
  3. Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. ISBN 0-08-037941-9.
  4. Hitchman, Michael A.; Lichon, Michael; McDonald, Robbie G.; Smith, Peter W.; Stranger, Robert "Crystal and molecular structure of chromium(II) sulfate pentahydrate and single-crystal electronic spectra and bonding of CrSO4·5 H2O, copper sulfate pentahydrate and CuSO4·5 D2O" Journal of the Chemical Society, Dalton Transactions 1987, pp. 1817-22. doi:10.1039/DT9870001817
  5. Dahmen, T.; Glaum, R.; Schmidt, G.; Gruehn, R. "Preparation and crystal structure of chromium(2+) sulfate trihydrate" Zeitschrift für Anorganische und Allgemeine Chemie 1990, volume 586, pp. 141-8. doi:10.1002/zaac.19905860119

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