Chromic Oxide (chromium(III) oxide; chromia; chromium sequioxide; green cinnabar).
Crâ‚‚03. CAS: 1308-38-9.
Properties: Bright-green, extremely hard crystals; d 5.2; mp 2435C; bp 4000C; insoluble in water, acids, and alkalies.
Derivation:
(a) By heating chromium hydroxide,
(b) by heating dry ammonium dichromate,
(c) by heating sodium dichromate with sulfur and washing out the sodium sulfate.
Hazard: Toxic by ingestion and inhalation. TLV: 0.5 mg/m³ of air.
Use: Metallurgy, green paint pigment, ceramics, catalyst in organic synthesis, green granules in asphalt roofing, component of refractory brick, abrasive.