Chromium(II) sulfate

Chromium(II) sulfate
	Crystalline sample wet with ethanol
	Structure of chromium(II) sulfate pentahydrate (CrSO4·5H2O) Chromium, Cr Sulfur, S Oxygen, O Hydrogen, H
Names
	IUPAC name Chromium(2+) sulfate
	Other names Chromous sulfate; Chromous sulphate;
Identifiers
CAS Number	13825-86-0 (anhydrous); 15928-77-5 (pentahydrate); 19512-13-1 (trihydrate);
3D model (JSmol)	anhydrous: Interactive image; pentahydrate: Interactive image;
ChemSpider	55589 (anhydrous);
PubChem CID	61686 (anhydrous);
UNII	Y0C99N5TMZ (anhydrous) ; 990MUV05EC (pentahydrate) ;
CompTox Dashboard (EPA)	DTXSID80160555 ;
	InChI Key: RYPRIXSYXLDSOA-UHFFFAOYSA-L; Key: RYPRIXSYXLDSOA-NUQVWONBAQ;
	SMILES anhydrous: [Cr+2].[O-]S(=O)(=O)[O-]; pentahydrate: [OH2+][Cr-3]([OH2+])([OH2+])([OH2+])O(S(=O)(=O)[O-]).O;
Properties
Chemical formula	CrSO4 (anhydrous); CrSO4·5H2O (pentahydrate)
Molar mass	148.05 g/mol (anhydrous); 238.13 g/mol (pentahydrate)
Appearance	Blue crystalline solid (pentahydrate)
Solubility in water	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 is an inorganic compound with the chemical formula Cr S O₄. Several hydrated salts are known (CrSO₄·nH₂O). The pentahydrate (CrSO₄·5H₂O) is a blue solid that dissolves readily in water. Solutions of chromium(II) are easily oxidized by air to Cr(III) species.

Structure

In aqueous solution, 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.^[1]^[2]

Preparation

The salt is produced by treating chromium metal with aqueous sulfuric acid:^[3]

Cr + H₂SO₄ + 5 H₂O → CrSO₄·5H₂O + H₂

It can be produced through the reaction of sulfate salts and chromium(II) acetate^[4] or, for in situ use, the reduction of chromium(III) sulfate with zinc.^[5]

Uses

Solutions of Cr(II) are used as specialized reducing agents of value in organic synthesis.^[5]

References

↑ Hitchman, Michael A.; Lichon, Michael; McDonald, Robbie G.; Smith, Peter W.; Stranger, Robert (1987). "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: 1817–22. doi:10.1039/DT9870001817.
↑ Dahmen, T.; Glaum, R.; Schmidt, G.; Gruehn, R. (1990). "Zur Darstellung und Kristallstruktur von CrSO₄·3H₂O" [Preparation and Crystal Structure of Chromium(2+) Sulfate Trihydrate]. Zeitschrift für Anorganische und Allgemeine Chemie. 586: 141–8. doi:10.1002/zaac.19905860119.
↑ Handbook of Preparative Inorganic Chemistry, 2nd Ed. Edited by G. Brauer, Academic Press, 1963, NY. Vol. 2. p. 1365.
↑ Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. doi:10.1016/C2009-0-30414-6. ISBN 978-0-08-037941-8.
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

[1] Hitchman, Michael A.; Lichon, Michael; McDonald, Robbie G.; Smith, Peter W.; Stranger, Robert (1987). "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: 1817–22. doi:10.1039/DT9870001817.

[2] Dahmen, T.; Glaum, R.; Schmidt, G.; Gruehn, R. (1990). "Zur Darstellung und Kristallstruktur von CrSO₄·3H₂O" [Preparation and Crystal Structure of Chromium(2+) Sulfate Trihydrate]. Zeitschrift für Anorganische und Allgemeine Chemie. 586: 141–8. doi:10.1002/zaac.19905860119.

[3] Handbook of Preparative Inorganic Chemistry, 2nd Ed. Edited by G. Brauer, Academic Press, 1963, NY. Vol. 2. p. 1365.

[4] Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. doi:10.1016/C2009-0-30414-6. ISBN 978-0-08-037941-8.

[OS-5] 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

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