The experimental Li56La24Zr16O96 crystal structures adopted for these calculations were the acentric cubic (I-43d), cubic (Ia-3d), and tetragonal (I41/acd). For the cubic modifications disordered lithium distributions were selected to satisfy experimental occupancies and to avoid unfavorable nearest-neighbor occupations. The resulting Li occupancies in the I-43d space group for the 12a/12b and 48e sites were 1.0 and 0.667, respectively; for the Ia-3d space group, the 24d and 96h site occupancies were 0.542 and 0.448, respectively. Cobalt was positioned on the 12a and 48e lithium sites in the I-43d structure, on the 24d/96h sites in Ia-3d, and on 8a and 16f sites in I41/acd. The lithium concentration in the simulation cell was adjusted to accommodate the Co 2+ and Co 3+ oxidation states.