Crystal structure of Cu 3Bi(TeO 3) 2O 2Cl: a Kagomé lattice type compound

Abstract

Single crystals of Cu 3Bi(TeO 3) 2O 2Cl were synthesised via a transport reaction in sealed evacuated quartz glass tubes from a starting mixture of CuO, CuCl 2, Bi 2O 3, and TeO 2. The new compound Cu 3Bi(TeO 3) 2O 2Cl crystallizes in the orthorhombic space group Pcmn, a = 6.3179 ( 8 ) , b = 9.8524 ( 12 ) , c = 14.358 ( 2 ) Å , Z = 4 . Full matrix least squares refinement gave an R1 value of 0.0372 using 936 independent reflections. The structure is a layered compound where the building units are [Cu1O 4] square planes, [Cu2O 4Cl] square pyramids, [BiO 6+2] polyhedra, and [TeO 3E] tetrahedra (E being the 5s 2 lone pair of Te(IV)), joined through sharing of edges and corners. The Cu ions in the Cu O layers resemble a distorted Kagomé lattice. The Cu O planes are only connected by the two longest Bi O bonds (2.83 Å) in the [BiO 6+2] coordination polyhedra. The Cl ions and the Te lone pairs are located in tunnels in the structure along [001].