Title: Boric Anhydride
CAS Registry Number: 1303-86-2
CAS Name: Boron oxide
Synonyms: boron trioxide; boric oxide; boron sesquioxide
Molecular Formula: B2O3
Molecular Weight: 69.62
Percent Composition: B 31.06%, O 68.94%
Literature References: Prepn of crystalline form: McCulloch,
J. Am. Chem. Soc. 59, 2650 (1937). Review of toxicology and human exposure:
Toxicological Profile for Boron (PB93-110674, 1992) 110 pp.
Properties: Colorless, brittle, vitreous, semitransparent, hygroscopic lumps or hard, white crystals. d (amorph) 1.8; d (cryst) 2.46. mp (cryst) 450°. Slowly sol in 30 parts cold, or 5 parts boiling water; sol in alcohol, glycerol.
Keep dry.
Melting point: mp (cryst) 450°
Density: d (amorph) 1.8; d (cryst) 2.46
NOTE: Has been improperly called
anhydrous boric acid or
fused boric acid.
CAUTION: Potential symptoms of overexposure are irritation of eyes, skin, respiratory system; cough; conjunctivitis; skin erythema.
See NIOSH Pocket Guide to Chemical Hazards (DHHS/NIOSH 97-140, 1997) p 30.
Use: In metallurgy; in analysis of silicates to determine SiO2 and alkalies; in blowpipe analysis.
