Quetzalcoatlite:: A new octahedral-tetrahedral structure from a 2 x 2 x 40 μm3 crystal at the Advanced Photon Source-GSE-CARS Facility

The structure of quetzalcoatlite, Zn6Cu3(TeO3)(2)O-6(OH)(6)(AgxPby)Clx+2y, x + y less than or equal to 2, Z = 1, was solved and refined using data collected at the Advanced Photon Source-GSE-CARS facility, using a 2 x 2 x 40 mu m(3) single crystal. The structure is trigonal, space group P (3) over bar 1m, a = 10.145(1), c = 4.9925(9) Angstrom, V = 445.0(1) Angstrom(3). and was refined to R = 5.1 for 395 unique observed reflections. Te6+O6, octahedra and Jahn-Teller distorted Cu2+O4OH)(2) octahedra share edges to form Layers parallel to (001), and ZnO2(OH)(2) tetrahedra share vertices to form six-member rings parallel to (001). Layers of octahedra and tetrahedra alternate along c, and form a new framework structure by vertex sharing. Channels through the framework parallel to ( are occupied by Ag, Pb, and Cl ions. Electron microprobe analysis revealed Ag and Cl overlooked in the original microchemical analysis. Up to one-third of the Ag was substituted by Pb, and a Pb-rich analog may exist.