2225. Chromic Hydroxide

Nomenclature

CAS number: 1308-14-1
Chromium hydroxide; chromic oxide gel; chromic oxide, hydrous.
CrH3O3; mol wt 103.02.
Cr 50.47%, H 2.94%, O 46.59%.
Cr(OH)3.

Description and references

Occurs only as hydrates. Prepn: Ruthroff, Inorg. Synth. 2, 190 (1946); Hein, Herzog in Handbook of Preparative Inorganic Chemistry vol. 2, G. Brauer, Ed. (Academic Press, New York, 2nd ed., 1965) pp 1345-1346.

Derivative

Trihydrate.
Cr(OH)3.3H2O; mol wt 157.06.
Cr 33.11%, O 61.12%, H 5.78%.

Properties

Or Cr2O3.9H2O, blue-green powder. Practically insol in water. Sol in dil mineral acids when freshly prepd, giving blue or green soln; becomes insol in acids on aging. Cr(OH)3.nH2O, shining, vitrous, jet-black particles. Useful as catalyst in dehydrogenation of alcohols and paraffins, hydrogenation of olefins.

Use

As pigment; in tanning industry; as mordant; as catalyst for organic reactions.