Chromium trioxide

The acid anhydride of chromic acid is chromium trioxide or chromium(VI) oxide; industrially, this compound is sometimes sold as "chromic acid". This compound is an intensely-colored dark red/orange brown, water-soluble, granular solid which is stable by itself, but is a strong oxidant which will react when mixed with many things that can be oxidized. Ethanol, for example, will ignite on contact with it.

Production
Chromium trioxide is produced commercially by the reaction of sodium dichromate with concentrated sulfuric acid.

Structure and chemistry
Chromium trioxide consists of chains of tetrahedrally coordinated chromium atoms that share vertices. Each chromium atom therefore has "half share of two oxygen atoms" and two oxygen atoms that are not shared, giving an overall stoichiometry of 1:3.

Chromium trioxide decomposes above 197°C liberating oxygen eventually giving Cr2O3. The reaction of chromium trioxide with organic substances is potentially explosive. In spite of this, CrO3 is used in organic chemistry as an oxidant, often dissolved in acetic acid, or acetone in the case of the Jones oxidation.

Safety
Chromium trioxide is highly toxic, corrosive, and carcinogenic.