AlVO 3, a metal-deficient spinel

Hydrogen reduction of AlVO ₄ at 1000°C yields AlVO ₃ with a metal-deficient spinel structure ( Al_{2}/{3}) [ Al_{2}/{3}V_{1 {1}/{3}}] O₄. X-ray, neutron, and electron diffraction examination of the compound showed that aluminium atoms randomly occupy two-thirds of the available tetrahedral sites within a spinel unit cell of edge 8.422 ± .003 Å. Magnetic suseptibility measurements showed a Néel point at approximately 270°K, and neutron diffraction data taken at 4.2°K is consistent with an antiferromagnetic alignment of the V ³⁺ ions in the B spinel sites such that spin cancellation occurs within the symmetry of the cubic cell. The compound is thermally stable to 1300°C, but at 100 kbar and 900°C was transformed to two corundum-type phases very close to the end-member compositions Al ₂O ₃ and V ₂O ₃.