Chromium(IV) oxide

Chromium dioxide

Brown to black solid

Fixed

4.89 g · cm -3

Decomposition above 250 ° C.

Insoluble in water

Attention

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Chromium ( IV) oxide ( CrO2 chemical formula ) is the oxide of the tetravalent chromium.

Production and representation

First synthesized, it was purified by Norman L. Cox, a DuPont chemist, by the decomposition of chromium ( VI) oxide in the presence of water at temperatures around 500 ° C and a pressure of 200 MPa.

Properties

Chromium ( IV) oxide is a brown to black solid. It crystallizes in a tetragonal rutile structure.

Use

The ferromagnetic and electrically conductive crystals of acicular shape, which makes them suitable for their use as magnetic pigment in magnetic tapes. Commercially, it was brought by DuPont in the late 1960s as a recording material under the brand name Crolyn on the market.