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|Section2= |Section3= |Section4= |Section5= }} Chromium(III) oxide is the inorganic compound of the formula Cr2O3. It is one of the principal oxides of chromium and is used as a pigment. In nature, it occurs as the rare mineral eskolaite. ==Structure and properties== Cr2O3 adopts the corundum structure, consisting of a hexagonal close packed array of oxide anions with 2/3 of the octahedral holes occupied by chromium. Similar to corundum, Cr2O3 is a hard, brittle material (Mohs hardness 8-8.5).〔 It is antiferromagnetic up to 307 K, the Neel temperature.〔J.E Greedan, (1994), ''Magnetic oxides'' in Encyclopedia of Inorganic chemistry R. Bruce King, Ed. John Wiley & Sons. ISBN 0-471-93620-0〕〔A. F. Holleman and E. Wiberg "Inorganic Chemistry" Academic Press, 2001, New York. ISBN 0-12-352651-5.〕 It is not readily attacked by acids or bases, although molten alkali gives chromates (salts with the CrO anion, not to be confused with the related mineral chromite). It turns brown when heated, but reverts to its dark green color when cooled. It is also hygroscopic. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Chromium(III) oxide」の詳細全文を読む スポンサード リンク
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