Hydrofluoric acid

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An aqueous solution of Hydrogen fluoride. Hydrofluoric acid is a colorless fuming liquid, that when concentrated contains 38% hydrogen fluoride. Hydrofluoric acid is one of the few materials that will dissolve silicon dioxide and, as such, is used for etching and polishing crystal, Glass, and enamel. It is also used for cleaning precious metals and removing Efflorescence from Brick and Stone.

Synonyms and Related Terms

HF; fluohydric acid; fluoric acid; hydrogen fluoride solution


  • Toxic by ingestion and inhalation.
  • Skin contact is corrosive. Causes severe burns.
  • Fisher Scientific: MSDS

Physical and Chemical Properties

Dissolves most metals except for Platinum and Gold.

Composition HF
CAS 7664-39-3
Melting Point -71 C
Density 1.15-1.18 g/ml
Molecular Weight mol. wt. = 20.005
Boiling Point 112.2 C

Resources and Citations

  • G.S.Brady, Materials Handbook, McGraw-Hill Book Co., New York, 1971 Comment: p. 405
  • 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 4831
  • The American Heritage Dictionary or Encarta, via Microsoft Bookshelf 98, Microsoft Corp., 1998
  • Michael McCann, Artist Beware, Watson-Guptill Publications, New York City, 1979