The crystal structure of choloalite

The crystal structure of choloalite, (Cu2.79Sb0.21)(Sigma 3.00)(Pb2.70Ca0.3 0)(Sigma 3.00)Te6.00O18.00Cl0.92, a 12.520(4) Angstrom, V 1963(2) Angstrom( 3), space group P4(1)32, Z = 4, has been solved by Patterson and direct met hods, and refined to an R index of 5.3% based on 956 unique reflections mea sured using MoKa radiation on an automated four-circle diffractometer. The structure consists of distorted TeO6 octahedra, Cu phi(5) square pyramids ( where phi = 0 and Cl), Pb(1)O-9 triaugmented trigonal prisms. and Pb(2)O-12 icosahedra. The Pb(1)O-9 polyhedra polymerize to form a three-dimensional network, as do the Cu phi(5) square pyramids and Pb(2)O-12 polyhedra. The t wo networks fit together in three-dimensional space, leaving voids that are filled by the TeO6 octahedra. it is likely that the ideal formula of cholo alite is CuPbTe24+O6, with CuO4 square planes as opposed to Cu phi(5) squar e pyramids.