Boric acid

Description

A white crystalline powder that occurs in nature as the mineral sassolite. Commercially, boric acid is primarily synthesized from borax and it is used widely as an antiseptic, insecticide, flame retardant, wood preservative, and precursor to other boron compounds. It is also used to produce glass, enamels, and porcelain. As an insecticide, it is commonly used as a powder for indoor species, such as cockroaches, silverfish, ants, termites, and black carpet beetles often in a mixture with silica dust called B + S. Boric acid can also be found as a buffer in photo processing solutions, and a mordant for printing and dyeing.

FTIR

Chemical structure

Synonyms and Related Terms

boracic acid; orthoboric acid; acide borique (Fr.); borsaure; NC1-C56417; Borofax; B + S ; Kill-Off; Boozuur

Risks

• May cause toxicity by ingestion and skin contact. LD50 = 5000 mg/kg
• Noncombustible.
• ThermoFisher: SDS

Physical and Chemical Properties

• Colorless, transparent crystals or white powder
• Soluble in water, ethanol, glycerol.
• Composition = H₃BO₃ (mol.wt. = 61.8 g/m)
• CAS = 10043-35-3
• Melting Point = 171 C (dec)
• Density = 1.4347 g/ml

Resources and Citations

• MuseumPests.net: Pesticide Database
• Nancy Odegaard, Alyce Sadongei, and associates, Old Poisons, New Problems, Altimira, Walnut Creek, CA, 2005
• Richard S. Lewis, Hawley's Condensed Chemical Dictionary, Van Nostrand Reinhold, New York, 10th ed., 1993
• Van Nostrand's Scientific Encyclopedia, Douglas M. Considine (ed.), Van Nostrand Reinhold, New York, 1976
• Random House, Webster's Encyclopedic Unabridged Dictionary of the English Language, Grammercy Book, New York, 1997
• The Merck Index, Martha Windholz (ed.), Merck Research Labs, Rahway NJ, 10th edition, 1983 Comment: entry 1364
• The American Heritage Dictionary or Encarta, via Microsoft Bookshelf 98, Microsoft Corp., 1998
• G.S.Brady, Materials Handbook, McGraw-Hill Book Co., New York, 1971 Comment: p. 109
• Lynda A. Zycherman, J.Richard Schrock, A Guide to Museum Pest Control, FAIC and Association of Systematics Collections, Washington DC, 1988
• Michael McCann, Artist Beware, Watson-Guptill Publications, New York City, 1979
• G.Caneva, M.P.Nugari, O.Salvadori, Biology in the Conservation of Works of Art, ICCROM, Rome, 1991
• Susan E. Schur, Conservation Terminology: A review of Past & Current Nomenclature of Materials, Technology and Conservation, Spring (p.34-39); Summer (p.35-38); Fall (p.25-36), 1985
• Photographic chemicals: www.jetcity.com/~mrjones/chemdesc.htm
• Wikipedia: Boric acid accessed Oct. 2026