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Forthcoming article in Acta Crystallographica Section B Structural Science, Crystal Engineering and Materials



Acta Crystallographica Section B: Structural Science, Crystal Engineering and Materials publishes scientific articles related to the structural science of compounds and materials in the widest sense. Knowledge of the arrangements of atoms, including their



 









Multidimensional structural variation in the cyano­trichite family of merotypes: camerolaite-3b-F-1
This is the first refined example of a cyano­trichite-group mineral in which long-range order of interlayer anions produces a superstructure.






Approaches to crystal structure landscape exploration
Three approaches to the exploration of the crystal structure landscape are outlined. These are crystal structure prediction, non-ambient crystallography and charge density analysis.



Temperature-induced order–disorder structural phase transitions of two-dimensional isostructural hexa­methyl­enetetramine co-crystals
This paper describes the single-crystal-to-single-crystal phase transitions triggered by molecular rotator ordering and structural order–disorder transformation in the two-dimensionally isostructural but energetically similar co-crystals, which are hexa­methyl­enetetramine-benzoic acid (1/2) and hexa­methyl­enetetramine-4-methyl­benzoic acid (1/2) at the transition temperatures of 257.5 (5) and 265.5 (5) K, respectively.



Evolution of the α-BaMg(CO3)2 low-temperature superstructure and the tricritical nature of its α–β phase transition
Using a high-sensitivity silicon detector and a micro-focus source, the norsethite [BaMg(CO3)2] low-temperature superstructure has been tracked across the temperature-driven α–β phase transition using single-crystal diffraction experiments. Systematic analysis of physical potential order parameters reveals the structure-related driving force and that the transition is tricritical in nature.



A note on the distortion theorem
Theoretical analysis of the bond length–bond valence correlation yielded an extension of the distortion theorem.



Effect of cationic substitution on the double-well hydrogen-bond potential in [K1−x(NH4)x]3H(SO4)2 proton conductors: a single-crystal neutron diffraction study
Single-crystal neutron diffraction was performed on [K1−x(NH4)x]3H(SO4)2 in order to obtain the exact hydrogen-bonding network. A correlation between the kinetics of the superprotonic phase transition in the crystalline state and hydrogen-bond strength is described.



Structural changes of relaxor ferroelectric Sr0.52Ba0.48Nb2O6 (SBN52) on quenching and reheating
Quenching enhances the disorder of the cation distribution in SBN52 crystals which leads to higher spontaneous electric polarization. The amplitudes of the incommensurate modulations are also increased.






Quantitative analysis of solid-state diversity in tri­fluoro­methyl­ated phenylhydrazones
The crystal structures of six tri­fluoro­methyl­ated phenyl­hydrazones have been studied in detail, particularly in terms of the solid-state diversity (like polymorphism and isostructurality) associated with different supramolecular architectures with H/CF3 substitution in the absence of any strong hydrogen bonding. The most stabilizing molecular building blocks have a higher dispersion contribution due to the greater overlap between molecular surfaces, leading to an increase in the magnitude of van der Waals interactions.






Phase transition sequences in tetra­methyl­ammonium tetra­chloro­metallates by X-ray diffraction and spectroscopic measurements
Structures and phase sequences for two tetra­methyl­ammonium tetra­chloro­metallate compounds have been determined as a function of temperature. Crystal-packing analysis and first-principles calculations were used to rationalize the experimentally determined sequence.



Quantitative characterization of new supramolecular synthons involving fluorine atoms in the crystal structures of di- and tetrafluorinated benzamides
New supramolecular synthons in crystal structures involving organic fluorine have been observed and characterized. The nature, energetics and topological properties of these contacts derived from electron-density studies establish their bonding character. The enhanced acidic nature of the participating H atoms is responsible for short, strong and highly directional contacts with fluorine. Their hydrogen-bonding character is thus established unequivocally, with a pronounced modification of the features associated with crystal packing.



Comparison of the crystal structures and thermochemistry of a novel soluble guanylate cyclase stimulator riociguat and its solvates
Intermolecular interactions and molecular conformations are compared for riociguat molecules in the solvent-free drug [form (II)] and three different solvate structures. Desolvation of solvates result in form (I) of the riociguat.