STRUCTURE MAPS FOR INTERMETALLIC PHASES USING 2ND MOMENT SCALING THEORY

Second moment scaled Huckel energies have been used to construct structure maps of intermetallic compounds with the stoichiometries ZA(3) and ZA(6). Z is an electropositive element from groups I-V or a lanthanide, and A is a late transition metal or main group element. The calculations were performed only on the covalent network of the A atoms. These structure maps plot the differences of the total energy as a function of electrons per atom for the stoichiometries above. With the use of only the covalent energy of the A network, these maps correctly demarcate the zones of stability exhibited for the structure types of AuCu3, TiNi3, TiCu3, BiF3, SnNi3, NdTe3, TiS3, SmAu6, CeCu6, and PuGa6. Some of these results are explained by means of a moments analysis.