Cover illustration: The crystal packing of catena-poly[[[heptaaqualanthanum(III)]--1,3-dioxo-2-oxa-1H,3H-phenalene-6,7-dicarboxylato-2O6:O7] hemi(4,8-dicarboxynaphthalene-1,5-dicarboxylate) dihydrate], omitting the H atoms. The lanthanum ions and water molecules of crystallization are depicted as small spheres. See Koner & Goldberg [Acta Cryst. (2008), C64, m264-m266].
NaIO2F2 is a new type of iodine(V) oxyfluoride with full O/F ordering and stereochemical activity of the lone pair, E, of iodine(V). A comparison with both homologous tellurium(IV) phases and rutile is presented.
Ce20Mg19Zn81 is a new structure type for rare earth–transition metal–magnesium intermetallic compounds, with a large cubic unit cell containing 480 atoms. Four different construction units following the geometric concept of nested polyhedral units are identified to simplify the structure.
The fundamental building unit for the title compound is the isolated anionic [B5O10]5− group. The local mm2 point symmetry of the ideal B5O10 group is broken, as the terminal O atoms have a small deviation from the corresponding six-membered ring planes.
The crystal structures of the new phases ScTeO3F and InTeO3F belong to two different structural types that also differ from that of the recently published series MTeO3F (M = Fe, Ga and Cr). A comparison is made of the three MTeO3F types.
Crystals of of Rb2Cu(VO2)2(PO4)2 have a novel structure type with a porous mixed framework formed by Cu, V and P oxo complexes. VO5 polyhedra in a trigonal bipyramidal configuration and PO4 tetrahedra share vertices to form eight-membered rings, which lie in layers perpendicular to the a axis of the monoclinic unit cell. Cu atoms at centres of symmetry have square-planar coordination and link these layers along  to form a three-dimensional anionic framework.
The structure of LiBaAlF6 is reported. Correlations between cationic radii and formula volumes for the known members of the LiAIIBIIIF6 family are developed that allow the prediction of crystal symmetry and space group based on the identities of the A and B cations.