The cation distribution in several CoGa_xAl_2–xO₄ solid solutions with x ranging from 0.00 to 2.00 has been studied by magnetic susceptibility, reflectance spectroscopy, lattice parameter variation and analysis of some reflections whose intensities are particularly sensitive to variation in the cation positions.

The results show that there is a small but definite change towards a random cation distribution when the preparation temperature is increased from 873 to 1473 K.

The X-ray and magnetic results show, moreover, that the fraction of Co²⁺ ions in octahedral sites varies with gallium and aluminium contents for the whole temperature series; this variation is, however, not linear. For samples quenched from 873 K, CoAl₂O₄ is 16% inverse; with increasing x, cobalt octahedral occupation first decreases up to x≈ 0.25 and then continuously increases reaching an inversion of 78% for the pure CoGa₂O₄ spinel.

The influence of x on cation distribution is explained in terms of anion polarization and/or crystal field stabilization energy effects.