[en] The use of ab initio molecular orbital calculations to aid in the characterization, i.e., structures and energies, of metal halide complexes present in high temperature salt vapors has been investigated. Standard LCAO-SCF methods were used and calculations were carried out using the minimal STO-3G basis set. The complexes included in this study were Al₂F₆, Al₂Cl₆, AlF₃ NH₃, AlCl₃ NH₃, and AlF₃ N₂. The Al₂X₆ complexes are found to have D/sub 2h/ symmetry in agreement with most experimental results. A planar form was found to be considerably higher in energy. The AlX₃ NH₃ complexes are found to have C/sub 3v/ symmetry with a small barrier to rotation about the Al-N axis. The AlF₃ N₂ complex is found to be weakly bound together with a binding energy of -8.2 kcal/mole at the STO-3G level