Crystal Structure of Chromium(III) oxide

Chromium(III) oxide (Cr₂O₃) is an amphoteric compound found in the rare mineral eskolaite. It is widely used in industrial products such as abrasives, refractories, semiconductors, pigments, alloys, textiles, printing, inks, catalysts, coloured glass, welded metals, and dyed polymers.

Cr₂O₃ is an antiferromagnetic crystal with a Neel temperature of 307 K. It crystallises in a corundum-type centrosymmetric trigonal structure in the R̅3c space group.Cr³⁺ combines with six equivalent O² atoms to form a mixture of corner-, face-, and edge-sharing CrO₆ octahedra.The corner-sharing octahedra have tilt angles between 47-60°. The tilt angles of the corner-sharing octahedra range from 47-60°. the Cr-O bond lengths are three shorter (1.97 Å) and three longer (2.02 Å). o²- bonds with four equivalent Cr³⁺ atoms to form a mixture of twisted corner-conjugated and edge-conjugated OCr₄ trigonal pyramids. the O²- bonds with six equivalent O² atoms to form a mixture of corner-conjugated and edge-conjugated CrO₆ octahedra.