Study of stacking interactions between two neutral tetra­thia­fulvalene molecules in Cambridge Structural Database crystal structures and by quantum chemical calculations

Stacking interactions in which two TTF molecules are displaced along their longer C₂ axis are dominant in crystal structures. The most frequent geometry has the strongest stacking interaction (−9.96 kcal mol⁻¹), calculated at very accurate CCSD(T)/CBS level. The other frequent geometries in crystal structures are also similar to very stable geometries of the minima on the calculated potential energy surface.

Epitaxial growth and structure of cobalt ferrite thin films with large inversion parameter on Ag(001)

Cobalt ferrite films about 4 nm thick were grown epitaxially on Ag(001) by molecular-beam epitaxy using a three-step method. Their spinel structure was solved by in situ grazing-incidence X-ray diffraction. The study is focused on the quantitative determination of inversion in the ferrite structure, which is a crucial parameter in determining its properties as a spin filter. This is tackled by employing an innovative technique as applied to ultrathin films, resonant X-ray diffraction.

SoftBV – a software tool for screening the materials genome of inorganic fast ion conductors

Introduced here is the new software tool softBV for the rapid prediction of migration barriers, attempt frequencies, conductivities and surface energies in structure models of solids utilizing a bond-valence-based adaptable force field.

Co-crystals of an organic tri­seleno­cyanate with ditopic Lewis bases: recurrent chalcogen bond interactions motifs

A recurrent chalcogen-bonded motif is observed in co-crystals of an organic tris­(seleno­cyanate) derivative with ditopic Lewis bases tetra­methyl­pyrazine, benzo­quinone and para-di­nitro­benzene.

Structural complexity of natural uranyl sulfates

Complexity of the crystal structure, which can be measured as the amount of Shannon information per atom or per unit cell, is the result of contributions from various factors, such as topological complexity, superstructure, hydration state, etc. The idealized (topological) symmetry of the structural units of the large and highly diverse group of uranyl sulfate minerals was determined and the concept of ladder diagrams was applied in order to quantify the particular contributions to the complexity values of the complete structures.

A new ternary compound with the BGa₈Ir₄ structure type in the Al–Au–Ir system

The discovery of a new Al–Au–Ir intermetallic compound is described; its crystal structure resolution is described and the Au/Ir mixed occupancy is discussed.

A proposal for coherent nomenclature of multicomponent crystals

A new, systematic, unambiguous and unified nomenclature applicable for co-crystals and other multicomponent solid materials is presented.

Influence of nanostructure formation on the crystal structure and morphology of epitaxially grown Gd₂O₃ on Si(001)

The epitaxial growth of Gd₂O₃ on Si(001) has been investigated using several methods, including X-ray and electron diffraction, and atomic force microscopy. The results show that crystal structure and morphology can be tuned by changing the growth conditions and are discussed within the framework of different physical effects.

Insight from electron density and energy framework analysis on the structural features of F_x-TCNQ (x = 0, 2, 4) family of molecules

Charge density and energy framework analysis provide quantitative insights into the relevance of intermolecular interactions and transport properties in the fluoro-substituted TCNQ family of molecules.

Solvent-mediated structural transformations of copper(II) coordination polymers induced by different short-chain alcohols

Induced by different short-chain alcohols, including methanol, ethanol and glycol, three distinct structural transformations have been observed for a three-dimensional Cu^II coordination polymer, via solvent-mediated processes.

Towards a qu­antitative bond valence description of coordination spheres – the concepts of valence entropy and valence diversity coordination numbers

New definitions of coordination number based on bond valences and related to diversity as well as Shannon entropy are proposed. They are called valence diversity and valence entropy coordination number.

The phase transitions of 4-amino­pyridine-based indolocarbazoles: twinning, local- and pseudo-symmetry

The phase transition behaviour and twinning of 4-aminopyridine-based indolocarbazoles are analyzed using the order–disorder theory and group–subgroup relationships.

The structure of nano-twinned rhombohedral YCuO_2.66 solved by electron crystallography

The complex oxide YCuO_2.66 is shown to be twinned at the nanoscale. Its structure was solved using precession electron diffraction.

Joel Bernstein (1941–2019)

Obituary for Joel Bernstein.