Cover illustration: A view of the molecular structure of bis(2,2'-methyliminodiethanolato)tetrakis(propane-1,3-diolato)trititanium(IV). Only the major conformations for the N-methyldiethoxoamine rings are shown. Displacement ellipsoids are drawn at the 30% probability level and H atoms have been omitted for clarity. See Kemmitt, Gainsford & Robson-Marsden [Acta Cryst. (2002), C58, m310-m312].
The crystal structures of monoclinic α-, orthorhombic β- and orthorhombic γ-Cu(H2PO2)2 have been determined at different temperatures. Despite having different space groups, the structures of the α- and β-polymorphs are very similar. The structures of the polymeric layers in the γ-polymorph are quite different.
A Rietveld refinement of a new γ polymorph for sodium gallate is reported. The structure shows the normal distribution of cations over two different sets of tetrahedral sites, as normally presented by other γ structures in many tetrahedral oxides.