The ternary oxides CrMnGaO4, NiMnGaO4, CuMnGaO4 and ZnMnGaO4, crystallize in the cubic spinel structure with lattice parametera=8.41±0.02 Å, 8.34±0.02 Å, 8.36±0.02 Å and 8.32±0.02 Å, respectively. The oxidation state of manganese in these spinels was determined x-ray spectroscopically. The site distribution was determined from the structural properties and calculated site preference energies of cations in the lattice. The ionic structures were found to be Ga3+ [Mn2+ Cr3+] O
42−
. Ga3+ [Cu2+ Mn3+] O
42−
, Mn2+ [Ga3+ Ni3+] O
42−
and Zn2+ [Mn3+ Ga3+] O
42−
.