Circumventing a challenging aspect of crystal structure determination from powder diffraction data

Schmidt and co-workers [Acta Cryst. (2022), B78, 195–213], report a strategy for structure determination from powder XRD data in which unit-cell determination and structure solution are combined within a single process, rather than handling them as sequential stages on the structure determination pathway. This strategy offers the prospect to achieve successful structure determination in cases for which conventional approaches for indexing powder XRD data prove to be challenging.

Effect of synchrotron X-ray radiation damage on phase transitions in coordination polymers at high pressure

The impact of X-ray irradiation on the high-pressure phase-transition behaviour of coordination polymers is highlighted with four example studies.

A first-order phase transition in Blatter's radical at high pressure

The intramolecular conformational response to the build-up of compressed intermolecular interactions in Blatter's radical (1,3-di­phenyl-1,4-di­hydro­benzo[e][1,2,4]triazin-4-yl) induces a second-order premonitory phase transition and then a first-order phase transition above 5.34 GPa.

Crystal structure, XANES and charge distribution investigation of krennerite and sylvanite: analysis of Au—Te and Te—Te bonds in Au_1–xAg_xTe₂ group minerals

Single-crystal XRD, XANES and charge distribution investigations of krennerite, sylvanite and calaverite are reported.

A novel energetic cocrystal composed of CL-20 and 1-methyl-2,4,5-tri­nitro­imidazole with high energy and low sensitivity

The design and synthesis of a cocrystal energetic material of CL-20 are reported.

Structure of the high-temperature phase of caesium nitrate – the importance of high-resolution data

A single-crystal X-ray structure determination of the high-temperature phase of CsNO₃ is presented and various structural models are discussed.

Morphotropism in fumarolic mineral-related anhydrous sulfates: novel representatives in A⁺₂M²⁺(SO₄)₂ and A⁺₂M²⁺₂(SO₄)₃ series

Two novel anhydrous sulfates Cs₂Cu(SO₄)₂ and Cs₂Co₂(SO₄)₃ were synthesized and structurally studied. These compounds belong to morphotropic series A⁺₂M²⁺(SO₄)₂ and A⁺₂M²⁺₂(SO₄)₃, respectively. Structural relationships in morphotropic series are discussed.

Compressibility of structural modulation waves in the chain compounds BaCoX₂O₇ (X = As, P): a powder study

High-pressure X-ray diffraction and Raman spectroscopic studies of modulated one-dimensional chain compounds BaCoX₂O₇ (X = As, P) were performed. Relationships between pressure-induced phase changes and the vibrational properties are analysed and discussed using complementary DFT-relaxed models, giving serious arguments for the vanishing of incommensurate structural modes above a first-order transition.

Revisiting the antiferromagnetic structure of Tb₁₄Ag₅₁: the importance of distinguishing alternative symmetries for a multidimensional order parameter

The magnetic structure of Tb₁₄Ag₅₁ is newly modelled under a magnetic space group, which is one of the possible alternative symmetries for the relevant irreducible representation. This approach results in a model that fits the data much better than that reported previously.

Investigation of crystal structures, energetics and isostructurality in halogen-substituted phosphoramidates

The geometric and energetic parameters responsible for the stability of halogenated phospho­ramidates enable the evaluation of the similarities and/or dissimilarities in geometrical features at the molecular level and the overall crystalline arrangement of molecules. The existence of a new supramolecular square synthon, based on C—H⋯π interactions, has been realized. This has implications in polymorphism and the design of futuristic materials.

Structure determination from unindexed powder data from scratch by a global optimization approach using pattern comparison based on cross-correlation functions

A new method for the structure determination of molecular crystals from unindexed powder data has been developed and successfully applied. The method performs a global optimization using pattern comparison based on cross-correlation functions.

Size–strain line-broadening analysis of anatase/brookite (TiO₂)-based nanocom­posites with carbon (C): XRPD and Raman spectroscopic analysis

To examine the structure and microstructure of anatase/brookite (TiO₂)-based nanocom­posites with carbon (C), two laboratory techniques, X-ray powder diffraction (XRPD) and Raman scattering, have been applied and reliable results were obtained. For the investigation of carbon, especially when present in small amounts, Raman scattering has an advantage over XRPD.

The role of free space in photochemical reactions in crystals at high pressure – the case of 9-methyl­anthracene

A detailed analysis of the influence of pressure on [4+4] photodimerization in crystals of 9-methylanthracene is presented. The reaction is 100% complete at high pressure, in contrast to ambient conditions.

π-Hole bonding in a new co-crystal hydrate of gallic acid and pyrazine: static and dynamic charge density analysis

The π-hole carbon bonding in a new hydrate cocrystal of gallic acid with pyrazine was characterized by static and dynamic charge density analysis.

A four-dimensional model for the Ba–Ti–O dodeca­gonal quasicrystal

A four-dimensional structure model for the Ba–Ti–O dodecagonal quasicrystal is described.

Powder X-ray diffraction as a powerful tool to exploit in organic electronics: shedding light on the first N,N′,N′′-tri­alkyl­diindolocarbazole

The crystal structure determination of N,N′,N′′-tri­butyl­diindolocarbazole from laboratory X-ray powder diffraction data is fully described. The analysis of the aromatic inter­molecular inter­actions allows the com­prehension of this π-conjugated system, which may have great potential with respect to organic electronics.

A new linear phenyl­oxazole–benzo­thia­diazole luminophore: crystal growth, structure and fluorescence properties

The synthesis, crystal growth, structure and fluorescence properties of a new linear luminophore consisting of five conjugated units of oxazole, phenyl­ene and a central benzo­thia­diazole fragment are reported.

Jack David Dunitz (1923–2021) and chemical crystallography

Comment on the article Properties and inter­actions – melting point of tri­bromo­benzene isomers

The high melting point of 1,3,5-tri­bromo­benzene is an entropy effect caused by its high molecular symmetry.

Response to comment on Properties and inter­actions – melting point of tri­bromo­benzene isomers

Trends in the melting points of analogous halogenated benzene isomers are rationalized in terms of molecular symmetry, crystal structure and interactions.

Principles of Inorganic Materials Design