Constrained evolutionary algorithm for structure prediction of molecular crystals: methodology and applications

A specially designed algorithm to predict the structure of complex crystals consisting of well defined molecular units is presented.

Structural chemistry of A₂MX₄ compounds (X = O, F) with isolated tetrahedral anions: search for the densest structure types

In three of the nine morphotropic A₂MX₄ series (nine different tetrahedral anions) the densest structure (spinel) is the stable structure for compounds with A cations of intermediate radius, in contrast to the classical homology rule. In some cases, denser phases have abnormally low overall binding energies.

Helical screw type magnetic structure of the multiferroic CaMn₇O₁₂ with low Cu-doping

The modulated crystal structure and modulated magnetic ordering of the multiferroic CaCu_xMn_7−xO₁₂ is studied by analysing neutron and synchrotron-radiation powder diffraction data with a model based on the magnetic superspace group R31′(00γ)ts.

Structure of (Ga₂O₃)₂(ZnO)₁₃ and a unified description of the homologous series (Ga₂O₃)₂(ZnO)_2n + 1

The structure of (Ga₂O₃)₂(ZnO)₁₃ has been determined and a unified description for structures in a homologous series (Ga₂O₃)₂(ZnO)_2n + 1 is presented using the (3 + 1)-dimensional superspace formalism.

Parallel stacking interactions in square-planar transition-metal complexes containing fused chelate and C₆-aromatic rings

The study of C_6-arom–chelate versus C_6-arom–C_6-arom stacking interactions in the crystal structures of square-planar transition metal complexes showed that the C_6-arom ring prefers to form stacking contacts with the chelate rings.

Phase transition at high pressure in Cu₂CO₃(OH)₂ related to the reduction of the Jahn–Teller effect

Malachite, Cu₂CO₃(OH)₂, transforms directly into a rosasite structure at high pressure as a result of the pressure-induced reduction of the Jahn–Teller distortion of CuO₆ coordination polyhedra.

Effect of pressure on crystalline L- and DL-serine: revisited by a combined single-crystal X-ray diffraction at a laboratory source and polarized Raman spectroscopy study

Information on the effect of pressure on hydrogen bonds, which could be derived from single-crystal X-ray diffraction at a laboratory source and polarized Raman spectroscopy, has been compared.

Low-temperature phase transition in glycine–glutaric acid co-crystals studied by single-crystal X-ray diffraction, Raman spectroscopy and differential scanning calorimetry

A low-temperature reversible phase transition at 220–230 K in glycine–glutaric acid co-crystals changes the conformation of every second glutaric acid molecule, but preserves the topology of the hydrogen-bond network, despite changes to the hydrogen-bond lengths and the space-group symmetry.

Relation between photochromic properties and molecular structures in salicylideneaniline crystals

Salicylideneaniline crystals exhibit photochromism under the following conditions: the dihedral angle between the two terminal benzene rings is greater than 30° and there is no intra- or intermolecular steric hindrance to inhibit a pedal motion within the crystal.

Voronoi–Dirichlet tesselation as a tool for investigation of polymorphism in molecular crystals with C_wH_xN_yO_z composition and photochromic properties

A relationship between photochromism and non-bonded interactions was investigated with the Voronoi–Dirichlet approach. Crystal structures of five sets of conformational polymorphs with the C_wH_xN_yO_z composition have been taken into account. It was demonstrated that each polymorph is characterized by a unique set of inter- and intramolecular contacts.

Invariom modeling of ceftazidime pentahydrate: molecular properties from a 200 second synchrotron microcrystal experiment

The structure of ceftadizime pentahydrate was determined from a 200 s experiment with synchrotron radiation. Combined with invariom refinement for rapid property calculation, high-throughput electron-density studies of hundreds of compounds become feasible.

Exact solution of the bond-valence sum rule for a set of coordination shells

The calculation scheme for determining the bond-valence parameters (r₀ and b) resulting in the exact solution of the bond-valence sum rule for a given set of coordination shells is presented.

Symmetriebeziehungen zwischen verwandten Kristallstrukturen