Crystal Structure of La3OBr[AsO3]2

Abstract

Colorless needles of the arsenite bromide La3OBr[AsO3]2 were synthesized from ammonium dihydrogen arsenate, ammonium bromide and lanthanum oxide in an NaBr/KBr flux at 900 °C. La3OBr[AsO3]2 crystallizes with the centrosymmetric tetragonal La3OCl[AsO3]2 type, space group P42/mnm. The structure was refined from single-crystal diffractometer data: a = 13.0431(15), c = 5.6127(7) Å , wR2 = 0.0454, 945 F2 values, and 39 variables. It consists of chains of trans-edge-sharing OLa4/2 tetrahedra which are coordinated by [AsO3]3− units via the oxygen atoms