Chromium oxide or chromia occurs in nature as a rare mineral called eskolaite and is a highly insoluble compound with high thermal stability, having the properties of both an acid and a base.
Manufacturing Process
It is produced through the reduction of sodium dichromate using sulfur at high temperatures indicated by the redox reaction
Na2Cr2O7 + S → Na2SO4 + Cr2O3
Ammonium dichromate, on heating, decomposes into chromium (III) oxide, water, and nitrogen
(NH4)2Cr2O7 → Cr2O3 + N2 + 4H2O
Chromium (iii) carbonate is heated to form chromium (III) oxide and carbon dioxide:
Cr2(CO3)3 → Cr2O3 + 3CO2
Ink, Glass, and Paint Industry
- used as the green pigment
Ceramic Industry
- colorant
- used to produce a faint green tinge in glazes
Leather Industry
- abrasive for polishing or stropping the edges of razors, knives, and surfaces of optical devices
