title: Particular topological complexity of lead oxide blocks in Pb31O22X18 (X = Br, Cl).
abstract: Dark-green platy crystals of the new compound Pb31O22Br10Cl8 (1) have been obtained by rapid quenching of a lead oxide halide melt. The structure of 1 (triclinic, P1, a = 12.1192(7) angstroms, b = 16.2489(10) angstroms, c = 18.3007(11) angstroms, alpha = 93.104(2) degrees, beta = 95.809(2) degrees, gamma = 111.252(1) degrees, V = 3325.4(3) angstroms3, Z = 2) can be viewed as incorporation of [PbX6]4- halide units (X = Br, Cl) into the defect PbO matrix. The latter represents a two-dimensional [O22Pb30]16+ cationic layer of OPb4 tetrahedra that can be derived from the [OPb] tetrahedral layer observed in tetragonal PbO. The layer consists of 22 symmetrically inequivalent OPb4 tetrahedra and represents the topologically most complicated arrangement of tetrahedra known to date.
authors: Department of Crystallography, St. Petersburg State University, University Emb. 7/9, 199034 St. Petersburg, Russia. skrivovi@mail.ru
authors: Sergey V
authors: SV
authors: Krivovichev
authors: Oleg I
authors: OI
authors: Siidra
authors: Evgenii V
authors: EV
authors: Nazarchuk
authors: Peter C
authors: PC
authors: Burns
authors: Wulf
authors: W
authors: Depmeier