Abstract
Crystals of Pb(AsO2)Cl [a = 6.933(1) Å, b = 9.923(2) Å, c = 11.374(2) Å; space group P212121; Z = 8] and Pb2(AsO2)3Cl [a = 5.368(1) Å, b = 8.189(3) Å, c = 19.51(1) Å; space group Pmcn; Z = 4] were synthesized under hydrothermal conditions. The crystal structure determination by direct methods and Fourier summations yielded R values of 4.6% resp. 4.8%.
Both compounds contain As(III)O3 pyramids linked by common O atoms to single AsO2 chains. The structure of Pb(AsO2)Cl is built up by formal AsO2 vierer single chains which are connected by PbO3Cl4 polyhedra to a framework. In the structure of Pb2(AsO2)3Cl formal AsO2 open-branched zweier single chains and PbO8Cl resp. PbO3Cl2 polyhedra are connected to layers parallel to (001); these layers are combined by weak van der Waals contacts only. This atomic arrangement explains the good cleavage parallel to (001).
