What is "chromium oxide"

Chromium oxide may refer to:

• Chromium(II) oxide, CrO
• Chromium(III) oxide, CrO
• Chromium dioxide (chromium(IV) oxide), CrO, which includes the hypothetical compound chromium(III) chromate
• Chromium trioxide (chromium(VI) oxide), CrO
• Chromium(VI) oxide peroxide, CrO
• Mixed valence species, such as Cr O

Chromium(III) oxide is the inorganic compound of the formula . It is one of the principal oxides of chromium and is used as a pigment. In nature, it occurs as the rare mineral eskolaite.

Chromium(II) oxide (CrO) is an inorganic compound composed of chromium and oxygen. It is a black powder that crystallises in the rock salt structure. Hypophosphites may reduce chromium(III) oxide to chromium(II) oxide:

It is readily oxidized by the atmosphere.

Chromium dioxide or chromium(IV) oxide is an inorganic compound with the formula CrO. It is a black synthetic magnetic solid. It once was widely used in magnetic tape emulsion. With the increasing popularity of CDs and DVDs, the use of chromium(IV) oxide has declined. However, it is still used in data tape applications for enterprise-class storage systems. It is still considered by many oxide and tape manufacturers to have been one of the best magnetic recording particulates ever invented.