2230. Chromic Sulfate

Nomenclature

CAS number: 10101-53-8
Sulfuric acid chromium(3+) salt (3:2); chromium(III) sulfate.
Cr2O12S3; mol wt 392.18.
Cr 26.52%, O 48.96%, S 24.53%.
Cr2(SO4)3.

Description and references

Prepn of anhydr salt by dehydration of hydrated forms: Rollinson, Bailar, Jr., Inorg. Synth. 2, 197 (1946). Toxicity data: Cavalli, Arch. Int. Pharmacodyn. 62, 330 (1939).

Properties

Peach-colored solid. d 3.012. Practically insol in water and acids. MLD in frogs, mice, rabbits (mg/kg): 37, 246.8, 215 i.v. (Cavalli).

Derivative

Hydrates.

Properties

Are known in both green and violet modifications, and have several degrees of hydration up to 18H2O: Lukaszewski, Redfern, Nature 190, 805 (1961); Udy in Chromium vol. 1, M. J. Udy, Ed., A.C.S. Monograph Series no. 132 (Reinhold, New York, 1956) pp 213-217, 288. The technical product comes in the form of a finely granular, dark-green flake or powder approximating the formula Cr2(SO4)3.10H2O. Readily sol in water. Almost insol in alc.

Derivative

Basic chromic sulfates.

Properties

Of the type Cr(OH)SO4.nH2O are of importance in the tanning industry: Udy, loc. cit. and pp 278-280, 305-308. Technical grades are available in two degrees of basicity, one-third and one-half, as finely granular dark-green flakes or powder contg about 25% Cr2O3. Readily sol in water.

Use

Insolubilization of gelatin; in catalyst prepn; as mordant in textile industry; in tanning of leather; in chrome plating; in manuf of Cr, CrO3, and Cr alloys; to improve dispersibility of vinyl polymers in water; in manuf of green varnishes, paints, inks, glazes for porcelain.