2229. Chromic Potassium Sulfate

Nomenclature

CAS number: 10141-00-1
Sulfuric acid chromium(3+) potassium salt (2:1:1); potassium chromic sulfate; potassium disulfatochromate(III); chromium(III) potassium sulfate.
CrKO8S2; mol wt 283.22.
Cr 18.36%, K 13.80%, O 45.19%, S 22.64%.
KCr(SO4)2.

Description and references

Dodecahydrate produced by reduction of K2Cr2O7 with SO2: Copson in ACS Monograph Series no. 132, entitled “Chromium,” vol. 1, M. J. Udy, Ed. (Reinhold, New York, 1956) p 281; electrolytic manuf: Nishihara et al., JP 60 2164 C.A. 55, 5200e (1961).

Derivative

Dodecahydrate.

Nomenclature

CAS number: 7788-99-0
Chrome alum.
CrKO8S2.12H2O; mol wt 499.40.
Cr 10.41%, K 7.83%, O 64.07%, S 12.84%, H 4.84%.

Description and references

K[Cr(SO6H4)2(H2O)2].6H2O: Duval, Chim. Anal. (Paris) 44, 102 (1962), C.A. 57, 9479d (1962).

Properties

Large, violet-red to black, octahedral, cubic crystals; ruby-red under transmitted light. d25 1.83. mp 89°; at 400° loses all its H2O. Sol in 4 parts cold, 2 parts boiling water; practically insol in alcohol. The aq soln is violet when cold, green when hot. The violet color returns after a few weeks at room temp.

Use

Mordant for dyeing fabrics uniformly; tanning leather; printing calico; rendering glue and gum insol; manuf ink, other chromium salts; waterproofing fabrics; hardening photographic emulsions.