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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



 



Structure, thermal expansion and incompressibility of MgSO4·9H2O, its relationship to meridianiite (MgSO4·11H2O) and possible natural occurrences
We have employed neutron and X-ray powder diffraction and density functional theory calculations to determine the structure and thermoelastic properties of a new hydrate in the MgSO4–H2O binary system, magnesium sulfate enneahydrate. We show that this 9-hydrate could occur naturally in certain hypersaline lakes on Earth and indicate where it may be formed as a more persistent mineral elsewhere in the solar system.



Crystal structure prediction by ionic network analysis: the example of (p–T–X)-structure relationships in olivines
A predictive method for the unit-cell parameters and atomic coordinates of ionic crystals is described. It is based on crystal structures known at systematically varying values of pressure, temperature or chemical composition, and applied to olivines



An unusual case of OD-allotwinning: 9,9′-(2,5-dibromo-1,4-phenylene)bis[9H-carbazole]
The title compound crystallizes as allotwins made up of two OD-polytypes with a maximum degree of order.



Deformations of the α-Fe2O3 trigonal lattice across the Néel temperature
Synchrotron radiation powder diffraction studies of synthetic hematite, α-Fe2O3, show that its crystal structure symmetry is monoclinic both below and above the Néel temperature, TN = 950 K.



Crystallographic features of ammonium fluoro­elpasolites: dynamic orientational disorder in crystals of (NH4)3HfF7 and (NH4)3Ti(O2)F5
The electron-density profiles of all the constituent atoms in the structures of ammonium fluoroelpasolites enabled the refinement of their real positions. The N2 atom does not escape a special 4b position, but the H2 atoms are disordered in the 96k position instead of 24e and together with the H3 atom in the 32f position they form eight spatial orientations of the ammonium group.



A priori checking of the light-response and data quality before extended data collection in pump–probe photocrystallography experiments
In picosecond and slower pump–probe diffraction experiments the collection of response–ratio correlation sets prior to full data collection provides an invaluable confirmation of the existence of a light-induced signal prior to full data collection. If a response to light exposure is observed, the quality of the data being collected can be assessed.



Characterization of fluorine-centered `F⋯O' σ-hole interactions in the solid-state
We report the experimental observation of a `unique' and `rare' F⋯O interaction, involving two electronegative atoms, having the characteristics of `short interatomic distance' and `high directionality' that provide robustness to the crystal packing. The characterization of these F⋯O contacts via different computational procedures establish the interaction to be dispersive in nature and the mutual polarization of an O atom by F and vice versa provides real physical insights into the role of atomic polarizability in interacting atoms in molecules in crystals.



A new tecton with parallel halogen-bond donors: a path to supramolecular rectangles
A new tecton, 1,8-diiodoethynylanthracene, with two parallel halogen-bond-donor sites was synthesized and characterized. This tecton is capable of forming two parallel halogen bonds at once, which makes it a useful building block for the construction of a variety of supramolecular squares and rectangles.