The effective formation energies and effective formation volumes of atomic defects in an ordered compound with the D03 structure were calculated by using statistical mechanics and  ab initio  electron theory. In Sb-rich compounds, the structural defect was a Ni vacancy on the a sub-lattice. The stoichiometric compound was a pentadefect system where, on average, four Ni vacancies were generated on the a sub-lattice plus one Ni antistructure atom. The calculations strongly supported conclusions drawn from neutron-scattering experiments.

Atomic Defects in D03-Ni3Sb: an ab initio Study G.Bester, B.Meyer, M.Fähnle: Physical Review B, 1998, 57[18], R11019-22