Octahedral-tetrahedral framework structures of InAsO4•H2O and Pbln(AsO4)(AsO3OH)

Indium arsenate(V) monohydrate, InAsO4 center dot H2O, (I), crystallizes in the structure type of MnMoO4 center dot H2O. The structure is built of In2O8(H2O)(2) dimers (mean In - O = 2.150 angstrom), corner-linked to slightly distorted AsO4 tetrahedra (mean As - O = 1.686 angstrom). The linkage results in a three-dimensional framework, with small voids into which the apical water ligand of the InO5(H2O) octahedron points. The hydrogen bonds in (I) are of medium strength. Lead(II) indium arsenate(V) hydrogen arsenate(V), PbIn(AsO4)(AsO3OH), (II), represents the first reported lead indium arsenate. It is characterized by a framework structure of InO6 octahedra corner-linked to AsO4 and AsO3OH tetrahedra. The resulting voids are occupied by Pb2O10(OH)(2) dimers built of two edge-sharing highly distorted PbO6(OH) polyhedra (mean Pb - O = 2.623 angstrom). The compound is isotypic with PbFeIII(AsO4)(AsO3OH). The average In - O bond length in (II) is 2.157 angstrom. In both arsenates, all atoms are in general positions.