Cover illustration: The unit-cell contents of catena-poly[sodium(I)--tetraethoxyborato], viewed along the a axis, showing the one-dimensional polymer chains along the twofold c axis. See Gainsford & Kemmitt [Acta Cryst. (2005), C61, m417-m418].
InAsO4·H2O crystallizes in the framework structure type of MnMoO4·H2O and is characterized by In2O8(H2O)2 dimers of edge-sharing InO5(H2O) octahedra corner-linked to AsO4 tetrahedra. PbIn(AsO4)(AsO3OH) also has an octahedral–tetrahedral framework structure and is isotypic with PbFeIII(AsO4)(AsO3OH).
CsGa(H1.5AsO4)2(H2AsO4) and isotypic CsCr(H1.5AsO4)2(H2AsO4) represent a novel structure type containing decorated kröhnkite-like octahedral–tetrahedral chains and a very short hydrogen bond (O⋯O distance ∼2.51 Å) involving a split H-atom position.
AgHg3SbO6 adopts the rhombohedral K4CdCl6 structure type featuring chains of alternating face-sharing SbO6 and AgO6 octahedra along . The octahedral chains are separated by Hg2+ cations in linear coordination.
La2RuO5 shows a phase transition from a monoclinic high-temperature to a triclinic low-temperature modification at approximately 160 K. Powder neutron diffraction at 293 and 1.5 K was used to study both structures.