Structure refinement and superspace description of the system Bi_2(n + 2)Mo_nO_6(n + 1) (n = 3, 4, 5 and 6)

The system of flexible composition Bi_2(n + 2)Mo_nO_6(n + 1) is described within the superspace formalism with two models, depending on the parity of the parameter n.

Unified (3 + 1)-dimensional superspace description of the 2212-type stair-like [Bi₂Sr₃Fe₂O₉]_m[Bi₄Sr₆Fe₂O₁₆] family of compounds

Two commensurate members (m = 4, 5) of the 2212 stair-like family of compounds with the composition [Bi₂Sr₃Fe₂O₉]_m[Bi₄Sr₆Fe₂O₁₆] have been analyzed and refined in the (3 + 1)-dimensional superspace framework. Both compounds are described by a unique model, including displacive modulations. The assumption of the validity of the proposed model for a range of compositions allows a realistic prediction of the structures of other members of the family.

The natural tiling approach to cation conductivity in KAlO₂ polymorphs

A detailed analysis of correlations between structural features and cation conductivity is performed for KAlO₂ polymorphs in a wide temperature range of 300–1023 K. To explore the migration maps of K⁺ cations we have used neutron diffraction data and applied for the first time a novel algorithm based on the natural tiling concept and implemented it into the program package TOPOS.

On the charge transfer between conventional cations: the structures of ternary oxides and chalcogenides of alkali metals

The structure of ternary oxides and chalcogenides of alkali metals can be better understood by assuming the electron transfer between cations, in an extension of the Zintl–Klemm concept.

Crystallographic input data for (001)-, (110)- and (111)-oriented superlattices

The necessary crystallographic input data are given for electronic-structure calculations of supercells with the (111), (001) or (110) orientations. They are applied to calculations on GaAs/AlAs superlattices of different thicknesses.

[Ni(MeCN)(H₂O)₂(NO₃)₂]·(15-crown-5)·MeCN: detailed study of a four-phase sequence that includes an intermediate modulated phase

Acetonitrilediaqua-κ¹O-nitrato-κ²O-nitratonickel(II) 15-crown-5 acetonitrile solvate was studied by single-crystal X-ray diffraction at intervals of 10 K in the range 90–273 K as the crystal passed, without obvious damage, through three phase transitions. The phase sequence includes an intermediate modulated phase that seems to be a kind of striped hybrid of the phases stable at immediately higher and lower temperatures.

Synthesis, structure and spectroscopic properties of a novel compound bis(benzylamino)silver(I) benzylcarbamate

Bis(benzylamino)silver(I) benzylcarbamate contains silver atoms coordinated to two nitrogen atoms of amino groups from different benzylamine molecules; metal–oxygen interactions are absent in the crystal structure. The title compound exhibits fluorescence properties.

Structure determination of L-arabinitol by powder X-ray diffraction

The crystal structure of L-arabinitol at room temperature was solved from its powder X-ray diffraction pattern. The starting structural model was found by the simulated annealing method. The structure was obtained through Rietveld refinements with soft restraints on the interatomic bond lengths and bond angles. The H atoms of hydroxyl groups were localized by a minimization of the crystalline energy.

X-ray diffraction and Raman study of DL-alanine at high pressure: revision of phase transitions

Structural changes in DL-alanine at pressures up to 8.3 GPa are not related to phase transitions.

A time-resolved powder diffraction study of in-situ photodimerization kinetics of 9-methylanthracene using a CCD area detector and parametric Rietveld refinement

The kinetics of the 9-methylanthracene photodimerization reaction was examined by time-resolved powder diffraction using a CCD detector and parametric Rietveld refinement.

Cocrystals of 5-fluorocytosine. I. Coformers with fixed hydrogen-bonding sites

Cocrystallization attempts with 5-fluorocytosine yielded eight cocrystals and two structures of a single compound. In six cocrystals, the expected heterodimers held together by two or three hydrogen bonds are present. Ab initio energy calculations helped to rationalize the intermolecular hydrogen-bonding patterns observed in the crystal structures.

Cocrystals of 5-fluorocytosine. II. Coformers with variable hydrogen-bonding sites

Five cocrystals (four with 5-fluorocytosine and one with 6-aminoisocytosine) are presented to study the influence of complementary binding on conformational flexibility and the tautomeric equilibrium.

42 salt forms of tyramine: structural comparison and the occurrence of hydrate formation

A structural study of 42 salt forms of the phenylethylamine tyramine examines cation conformation, cation packing and hydrogen bonding as well as showing that hydrate formation is favoured both by higher total numbers of potential hydrogen-bond acceptors and donors and by lower donor:acceptor ratios.

Pressure-induced phase transitions in L-alanine, revisited. Corrigendum

Corrigendum to the data published in the article by Tumanov et al. [(2010), Acta Cryst. B66, 458–471].