issue contents

ISSN: 2052-5206

April 2023 issue

Highlighted illustration

Cover illustration: Image from Grzechnik et al. [(2023). Acta Cryst. B79, 104–113] showing an animated version of the modulated structure highlighting the different configurations present in the structure of mixed valence A2V3O8 vanadate fresnoite at room temperature. The structure (P4bm, Z = 2) is built up of layers with corner-sharing V5+O4 tetrahedra and V4+O5 square pyramids separated by the A+ cations, where A+ is K+, Rb+, Cs+ or (NH4)+.

scientific commentaries

link to html
An analysis of neutron and x-ray diffuse scattering from yttria-stabilized zirconia by Schmidt et al. [Acta Cryst. (2023), B79, 137–147] uses three-dimensional pair-distribution functions (3D-ΔPDF) to determine local structural correlations without the need for sophisticated modeling.

link to html
Nifedipine (NIF) molecules (L-type calcium channel antagonists) pack in solvated structures showing strikingly similar patterns, see Jones et al. [Acta Cryst. (2023), B79, 164–175]. How much do molecular shapes, such as the NIF molecule which resembles the letter T, matter in their associations in crystals?

research papers

link to html
The structures and phase transitions to the incommensurate structures in Rb2V3O8 and K2V3O8 mixed-valence vanadate fresnoites are studied with synchrotron single-crystal diffraction as a function of radiation dose at low temperatures and ambient pressure. Strategies to collect and analyse single-crystal diffraction data measured with very intense synchrotron radiation using modern low-noise pixel area detectors are discussed.

link to html
The modulation effectiveness of acetic acid, BTC (1,3,5-benzene tri­carb­oxy­lic acid) ligand and amino acids, including proline, alanine, glutamine, aspartic acid and histidine, for miniaturizing the size as well as changing the morphology of a novel alkaline earth metal–organic framework (BaBTC) is inspected. By using amino acid modulators, exceptionally proline, the crystallite size of BABTC is reduced from > 5 µm to 50 nm and its morphology is changed from rod-like to sheet. In addition, the BTC ligand investigation resulted in a new BaBTC-2 metal–organic framework.

link to html
The crystal structure of the α phase of Pigment Orange 13, used until the end of 2013 to print the front covers of Acta Crystallographica Section C and inter alia, was solved by analysis of diffuse scattering in electron diffraction data.

link to html
Three-dimensional difference pair distribution functions (3D-ΔPDFs) from X-ray and neutron diffraction experiments are used to identify local stabilization mechanisms in yttria-stabilized cubic zirconia.

link to html
Crystals of a coupled molecule of 4-biphenylcarboxy-(L)-phenylalaninate undergo normal to commensurately modulated phase transition at Tc ∼ 124 K that is characterized by torsional modulation typical of modulated structures and superstructures of polyphenyls yet unusual owing to asymmetric and unequal rotations governed by intramolecular and intermolecular constraints. The transition is presumably governed by significant suppression of atomic displacement parameters correlated to the evolution of amplitude of atomic modulation functions.

link to html
Y3(GaAlFe)5O12 monocrystalline garnet films (200 nm thick) with low saturation magnetization have been prepared on gadolinium gallium garnet substrates by liquid-phase epitaxy. As the growth temperature was changed, the stress state and elemental composition of the films were analyzed and calculated.

link to html
The formation of nifedipine solvates is explored and the desolvation pathways probed through a combination of variable-temperature X-ray powder diffraction, differential scanning calorimetry and thermal gravimetric analysis.

link to html
The crystal structures of Nd(SeO3)(HSeO3)·2H2O polymorphs show order–disorder (OD) character and can be described using the same OD groupoid family. The structural complexity parameters and DFT calculations of both polytypes show that the polytype structures are extremely close energy-wise and almost equally viable from the point of total energy of the structure.

addenda and errata

Follow Acta Cryst. B
Sign up for e-alerts
Follow Acta Cryst. on Twitter
Follow us on facebook
Sign up for RSS feeds