Three new copper-lead selenite bromides obtained by chemical vapor transport: Pb5Cu+4(SeO3)4Br6, Pb8Cu2+(SeO3)4Br10, and the synthetic analogue of the mineral sarrabusite, Pb5Cu2+(SeO3)4(Br,Cl)4

Three new copper-lead selenite bromides were synthesized by chemical vapor transport reactions. Pb5Cu+4(SeO3)4Br6 is monoclinic, space group C2/m, a = 17.7248(14), b = 5.5484(5), c = 12.7010(10) Å, β = 103.398(2)º, V = 1215.08(17) Å3, R1 = 0.024; Pb8Cu2+(SeO3)4Br10 is orthorhombic, space group I222, a = 9.5893(5), b = 12.4484(9), c = 12.7927(6) Å, V = 1527.08(15) Å3, R1 = 0.027; Pb5Cu2+(SeO3)4(Br,Cl)4 is monoclinic, C2/c, a = 24.590(6) Å, b = 5.5786(14) Å, c = 14.248(4) Å, β = 102.883(7)º, V = 1905.3(9) Å3, R1 = 0.026. The crystal structure of Pb5Cu+4(SeO3)4Br6 consists of two distinct parts: corner- and edge-sharing Cu+Br4 tetrahedra form infinite [Cu+4Br6]2- layers which alternate with [Pb5(SeO3)4]2+ layers. Pb8Cu2+(SeO3)4Br10 contains positively charged unique [Pb8Cu2+(SeO3)4]10+ rod-like chains with Cu2+ cations in the core. These chains are held together by Br- anions. Pb5Cu+4(SeO3)4Br6 and Pb8Cu2+(SeO3)4Br10 belong to new structure types. Pb5Cu2+(SeO3)4(Br,Cl)4 is a synthetic analogue of the mineral sarrabusite, Pb5Cu(SeO3)4Cl4, previously known from an electron diffraction study. The investigation of this synthetic equivalent of sarrabusite by conventional single-crystal X-ray diffraction provides a distinctly improved insight in this crystal structure. Cu atom has well-defined [2O+(2O+2X)] (X = halogen) distorted octahedral coordination. PbOn and SeO3 polyhedra interconnect via common oxygen atoms into [Pb5(SeO3)4]2+ layers parallel to (001). Cu2+ cations interconnect the layers into the framework with the large cavities filled by halide X anions. In all three new compounds described, a common feature is the formation of the selenophile substructure which is terminated by a 'lone-pair' shell that faces bromide complexes thus forming the surface of a halophile substructure. [ABSTRACT FROM AUTHOR]