cro3

from The Collaborative International Dictionary of English v.0.48
Chromic \Chro"mic\, a. (Chem.)
   Pertaining to, or obtained from, chromium; -- said of the
   compounds of chromium in which it has its higher valence.
   [1913 Webster]

   {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.
      [1913 Webster]
    

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