Tb₃Sn₇: polymorphism and crystal structure of high-temperature modification

The temperatures of non-variant transformations in the tin-rich side of the Tb–Sn binary system were refined using differential scanning calorimetry. The crystal structure of βTb₃Sn₇ was determined for the first time from single-crystal diffraction data. The structures of α- and β-modifications were analysed and a possible mechanism of polymorphic transformation proposed.

Crystal and magnetic structures of hexagonal YMnO₃

The available data on the structural and magnetic transitions in hexagonal YMnO₃ have been reviewed, making use of computer-aided symmetry analysis to list possible crystal and magnetic structures, and taking account of the capability of different methods to distinguish them. A favoured transformation sequence is presented.

Single-crystal metastable high-temperature C2/c clinoenstatite quenched rapidly from high temperature and high pressure

The single crystal of the C2/c HT-CEn end-member is synthesized by rapid pressure–temperature quenching. It is suggested that the single crystal has been formed from the high-pressure clinoenstatite.

Modulated crystal structure of Pr₂SbO₂

The crystal structure of commensurately modulated Pr₂SbO₂ was solved in the orthorhombic superspace group Immm(0β0)000 from a crystal twinned by reticular pseudomerohedry. The formation of Zintl-type Sb²⁻–Sb²⁻ dumbbells in Pr₂³⁺Sb²⁻O₂²⁻ is considered to be responsible for its semiconducting properties.

Applicability study of the structure-factor phase method for determining the polarity of binary semiconductors

The applicability of the structure-factor phase method in determining the polarity of binary semiconductors is investigated by dynamical simulations of convergent-beam electron diffraction. It was found that this method is efficient to determine the polarity of a sphalerite structure under certain conditions, and, reversely, limited to determine the polarity of a wurtzite structure.

Cationic radii from structures of extremely compressed solids

A novel system of cationic radii for metals is proposed, based on the compressibilities of solids at ultra-high pressures.

Kermesite, Sb₂S₂O: crystal structure revision and order–disorder interpretation

The structure of kermesite, Sb₂S₂O, was refined and interpreted as an order–disorder (OD) structure of layers. The maximum-degree-of-order (MDO) polytypes are derived, twinning explained, and desymmetrization discussed and evaluated. The interpretation requires the use of a non-standard pseudo-monoclinic octuple unit cell with extra centering points. Its relation to the primitive triclinic cell is displayed in the picture.

Sodium manganese fluoro­sulfate with a triplite structure

The crystal structure of NaMnSO₄F fluorosulfate compound has been solved, refined and compared with other alkali metal fluorosulfates and naturally occurring triplite-type minerals.

Orientation domains in vacancy-ordered titanium monoxide

Twelve orientation domain variants in vacancy-ordered titanium monoxide TiO_x and the crystallographic relationships among them were analyzed systematically by combining the group theory analysis and the electron diffraction technique.

Ferroelectric glycine silver nitrate: a single-crystal neutron diffraction study

The crystal structure of glycine silver nitrate (GSN) in a ferroelectric phase has been obtained by single-crystal neutron diffraction. It is suggested that the second-order Jahn–Teller behavior of the Ag ion in GSN leads to the structural phase change.

Alkali metal complexes of 6-methyl-2-pyridone: simple formulae, but not so simple structures

Polymeric alkali metal compounds with the simple formulae M(pyridonate)(solvent)_n display some novel structural features, including bridging of two metal ions by the N atom of a pyridonate ligand and quadruple bridging by water molecules.

Supramolecular association via Sb⋯S and C—H⋯S interactions in dimeric tris(N,N-di­methyldi­thiocarbamato-S,S′)antimony(III): an approach to overcome the concept of steric bulk on such interactions

Analysis of the supramolecular interactions found in some dimeric tris(alkyl and/or aryldithiocarbamato)antimony(III) compounds.

Charge density distribution of 3-(1-amino­ethyl­idene)-2-meth­oxy-2-oxo-2,3-di­hydro-2λ⁵-benzo[e][1,2]oxaphosphinin-4-one

Experimental and theoretical electron densities of an oxaphosphinane derivative are presented. The existing intramolecular hydrogen bond is found to be an isolated hydrogen bond as opposed to a possible resonance-assisted hydrogen bond. P—O bonds are found to possess a high degree of ionicity.

Clarification of possible ordered distributions of trivalent cations in layered double hydroxides and an explanation for the observed variation in the lower solid-solution limit

The sequence of hexagonal ordered distributions of trivalent cations that are possible in the octahedral layer of layered double hydroxides is clarified, including the link between the composition and the supercell a parameter. A plausible explanation is provided for the observed variation in the lower solid-solution limit.