What is "cro3"

Chromic \Chro"mic\, a. (Chem.) Pertaining to, or obtained from, chromium; -- said of the compounds of chromium in which it has its higher valence.

Chromic acid, 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.

Chromic anhydride, a brilliant red crystalline substance, CrO3, regarded as the anhydride of chromic acid. It is one of the most powerful oxidizers known.