ORDERING OF METAL ATOMS IN WURTZITE AND SPHALERITE STRUCTURES

The Zn atoms of the wurtzite or sphalerite structure ZnS) exhibit a he xagonal or cubic close packing with T-1 = 12 nearest and T-2 = 6 next- nearest neighbors. Ordered compounds such as CuFeS2, SbCu3S4, and SnFe Cu2S4 can be characterized by the self-coordination numbers T-1, T-2, and T-3 of the metal atoms and plotted on structural maps with coordin ates T-1, T-2, T-3. The three compounds, for example, are at the right border of the map which satisfies Pauling's electrovalence rule. The interaction between metal atoms is repulsive. Other compounds such as GeCu2Se3, beta-Ga2Se3, and alpha-LiSiNO are at different positions of the structure map with attractive interactions between metal atoms and violate Pauling's rule. Some new crystal structures and appropriate m etal atones are selected for the synthesis of new compounds. (C) 1998 Academic Press.