THE CRYSTAL-STRUCTURE OF PBFE[ASO4][ASO3(OH)]

Light green to nearly colourless crystals of PbFe[AsO4] [AsO3(OH)] wer e synthesized under moderate hydrothermal conditions (a = 4.846(2), b = 8.482(4), c = 15.560(6)Angstrom beta = 92.82(3)degrees, space group P2(1)/n, Z = 4). For a single-crystal structure determination, 110 var iable parameters were refined to R = 0.042, R(w) = 0.031 (1545 X-ray r eflections with F-0 > 3 sigma(F-0) and sin theta/lambda less than or e qual to 70 degrees). The crystal structure is characterized by a three -dimensional corner-connection of the FeO6 octahedra with the arsenate tetrahedra and the protonated arsenate groups. Each two PbO7 polyhedr a are edge-connectedto Pb2O12 dimers which are located within intersti tial holes.