1336. Boric Acid

Nomenclature

CAS number: 10043-35-3
Boric acid (H3BO3); boracic acid; orthoboric acid; Borofax (Burroughs Wellcome).
BH3O3; mol wt 61.83.
B 17.49%, H 4.89%, O 77.63%.
H3BO3.

Description and references

Occurs in nature as the mineral sassolite. Manuf: Faith, Keyes & Clark's Industrial Chemicals, F. A. Lowenheim, M. K. Moran, Eds. (Wiley-Interscience, New York, 4th ed., 1975) pp 153-158. Toxicity study: Smyth et al., Am. Ind. Hyg. Assoc. J. 30, 470 (1969). Review of toxicology and human exposure: Toxicological Profile for Boron (PB93-110674, 1992) 110 pp.

Properties

Colorless, odorless, transparent crystals, or white granules or powder; slightly unctuous to the touch. mp ≈171°. d 1.48. Phase diagram for the B2O3.H2O system: Kracek et al., Am. J. Sci. 35A, 143 (1938). Volatile with steam. pH: 5.1 (0.1 molar). One gram dissolves in 18 ml cold, 4 ml boiling water, in 18 ml cold, 6 ml boiling alcohol, in 4 ml glycerol; soly in water is increased by HCl, citric or tartaric acids. Soly of boric acid in glycerol solns of various concns: Sciarra, Elliott, J. Am. Pharm. Assoc. Sci. Ed. 49, 116 (1960). LD50 orally in rats: 5.14 g/kg (Smyth).

Caution

Potential symptoms of overexposure by ingestion or absorption are vomiting, diarrhea, abdominal cramps, erythematous lesions on skin and mucous membranes, circulatory collapse, tachycardia, cyanosis, delirium, convulsions, coma. Chronic use may cause borism (dry skin, eruptions, gastric disturbances). See E. Browning, Toxicity of Industrial Metals (Appleton-Century-Crofts, New York, 2nd ed., 1969) pp 90-97.

Use

For weatherproofing wood and fireproofing fabrics; as a preservative; manuf cements, crockery, porcelain, enamels, glass, borates, leather, carpets, hats, soaps, artificial gems; in nickeling baths; in buffers; cosmetics; printing and dyeing, painting; photography; for impregnating wicks; electric condensers; hardening steel. Also used as insecticide for cockroaches and black carpet beetles.

Therapeutic Category

Astringent, antiseptic.

Therapeutic Category (Veterinary)

Antibacterial and antifungal. Used chiefly in aqueous solution or powders for external use.

Keywords

Antiseptic/Disinfectant; Astringent