Title: Chromium(VI) Oxide
CAS Registry Number: 1333-82-0
CAS Name: Chromium oxide (CrO3)
Additional Names: chromic anhydride; chromium trioxide
Molecular Formula: CrO3
Molecular Weight: 99.99
Percent Composition: Cr 52.00%, O 48.00%
Literature References: Produced commercially by the action of concd H2SO4 on a soln of chromate or dichromate: Faith, Keyes & Clark's Industrial Chemicals, F. A. Lowenheim, M. K. Moran, Eds. (Wiley-Interscience, New York, 4th ed., 1975) pp 270-274.
Properties: Dark red, deliquesc bipyramidal prismatic crystals, flakes or granular power. d 2.70. mp 197°. Dec at 250° to Cr2O3 and O2. Very sol in water; sol in H2SO4. Powerful oxidizer; oxidizes alcohol and most other organic substances, sometimes with dangerous violence. Contact with combustible material may cause fire.
Melting point: mp 197°
Density: d 2.70
CAUTION: Potential symptoms of overexposure are respiratory system irritation, nasal septum perforation; liver and kidney damage; leukocytosis, leukopenia, monocytosis, eosinophilia; eye injury, conjunctivitis; skin ulcers, sensitization dermatitis. See NIOSH Pocket Guide to Chemical Hazards (DHHS/NIOSH 97-140, 1997) p 70. Chronic overexposure may lead to severe liver damage, CNS involvement and lung cancer. See Clinical Toxicology of Commercial Products, R. E. Gosselin et al., Eds. (Williams & Wilkins, 5th ed., 1984) Section II, p 108. See also Patty's Industrial Hygiene and Toxicology vol. 2C, G. D. Clayton, F. E. Clayton, Eds. (Wiley-Interscience, New York, 4th ed., 1994) p 1973-1985. Chromium hexavalent compounds are listed as known human carcinogens: Report on Carcinogens, Eleventh Edition (PB2005-104914, 2004) p III-63.
Use: Chromium plating; copper stripping; aluminum anodizing; corrosion inhibitor; photography; purifying oil and acetylene; hardening microscopical prepns; oxidizing agent in organic chemistry.
Therap-Cat-Vet: Has been used in solution as a topical antiseptic and astringent.