chromic acid

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. A corrosive, oxidizing acid, H₂CrO₄, occurring only as salts or in solution.
2. n. The anhydride of chromic acid, CrO₃, a purplish crystalline material that reacts explosively with reducing agents and is used in chromium plating, as an oxidizing agent, and to color glass and rubber.

Wiktionary

1. n. inorganic chemistry A corrosive acid, H2CrO4, known only in solution or as its salts, the chromates (from which it may be prepared); it is a very powerful oxidizing agent.

GNU Webster's 1913

1. adj. an acid, H2CrO4, analogous to sulphuric acid, not readily obtained in the free state, but forming well known salts, many of which are colored pigments, as chrome yellow, chrome red, etc.

WordNet 3.0

1. n. an unstable acid known only in solution and as chromate salts