Crystallography is more than crystal structures

New developments in neutron and synchrotron science and technology are discussed.

Coherent three-dimensional X-ray cryo-imaging

The combination of cryogenic sample temperatures with three-dimensional coherent diffractive imaging for the case of whole frozen-hydrated cells is discussed in the light of theoretical predictions of the achievable resolution.

Complexity at mesoscopic lengthscale

Modern materials are often complex in the structure at mesoscale. The method of pair-density function (PDF) is a powerful tool to characterize mesoscopic structure, bridging short- and long-range structures.

Demonstration of thin film pair distribution function analysis (tfPDF) for the study of local structure in amorphous and crystalline thin films

It is shown how normal-incidence X-ray total scattering can be used to obtain high-quality pair distribution functions from amorphous and crystalline thin films on much thicker substrates, allowing a range of studies of the local structure in film materials.

Crystal structures of eight mono-methyl alkanes (C₂₆–C₃₂) via single-crystal and powder diffraction and DFT-D optimization

The crystal structures of eight mono-methyl alkanes are solved from powder or single-crystal X-ray diffraction data, and optimized via DFT-D calculations.

A systematic structural study of halogen bonding versus hydrogen bonding within competitive supramolecular systems

An extensive structural study on hydrogen and halogen bonding in co-crystals has helped clarify the competition and balance between them in a practical supramolecular synthesis.

Percolating hierarchical defect structures drive phase transformation in Ce_1−xGd_xO_2−x/2: a total scattering study

Pair distribution function analysis up to tens of nanometres allows probing of the structural changes in Ce_1−xGd_xO_2−x/2 solid solutions at varying gadolinium concentrations. Dopant ions and oxygen vacancies form extended Gd₂O₃-like clusters (droplets) and nanodomains which, on increasing the Gd concentration, percolate and cause a long-range phase transformation. A general crystallographic rationale is presented which could be adopted to describe phase transformations in highly doped materials.

Exploration and exploitation of homologous series of bis­(acrylamido)alkanes containing pyridyl and phenyl groups: β-sheet versus two-dimensional layers in solid-state photochemical [2 + 2] reactions

Sixteen derivatives of the homologous series of bis(acrylamido)alkanes have been synthesized with the aim of systematic analysis of their crystal structures and their solid-state [2 + 2] reactivities. Seven out of the 16 found to have reactive alignments for solid-state [2 + 2] reactions yield dimers and polymers.

Human insulin polymorphism upon ligand binding and pH variation: the case of 4-ethylresorcinol

This study focuses on the effects of the organic ligand 4-ethylresorcinol on the crystal symmetry and lattice dimensions of human insulin using powder X-ray crystallography.

Serial femtosecond crystallography of soluble proteins in lipidic cubic phase

A new approach of using lipidic cubic phase as a carrier matrix for delivering soluble protein microcrystals for serial crystallography helps to dramatically reduce protein consumption. The structures of two soluble test proteins have been determined by this method using less than 0.1 mg of each protein.

A fluorescent paramagnetic Mn metal–organic framework based on semi-rigid pyrene tetra­carboxylic acid: sensing of solvent polarity and explosive nitroaromatics

Fluorescence quenching by paramagnetic metal ions is attenuated in an Mn metal–organic framework (Mn-MOF) based on a pyrene linker. Based on solvent-dependent emission, the Mn-MOF is shown to serve as a solvent polarity probe. Further, sensing of nitroaromatics is demonstrated with a detection limit of ∼125 p.p.m. for TNT.

Qu­antitative analysis of intermolecular interactions in orthorhombic rubrene

A combination of single-crystal X-ray and neutron diffraction experiments are used to determine the electron density distribution in orthorhombic rubrene. The topology of electron density, NCI analysis and energetics of intermolecular interactions clearly demonstrate the presence of π⋯π stacking interactions in the crystalline state.

Three-dimensional coherent X-ray diffractive imaging of whole frozen-hydrated cells

Since its first experimental demonstration in 1999, coherent diffractive imaging (CDI) has been applied to image a broad range of samples using advanced synchrotron radiation, X-ray free-electron lasers, high harmonic generation and electrons. Here, the first experimental demonstration of cryogenic CDI for quantitative three-dimensional imaging of whole frozen-hydrated cells is reported. As a proof of principle, the three-dimensional mass density of the sub-cellular organization of a Neospora caninum cell is determined based on its natural contrast.

Crystal chemistry of layered structures formed by linear rigid silyl-capped molecules

Silyl capped aryl bis-ene–yne compounds and their derivatives possess a rich crystal chemistry: merotypism, polymorphism, polytypism, twinning and incommensurate modulation.

Room-temperature serial crystallography using a kinetically optimized microfluidic device for protein crystallization and on-chip X-ray diffraction. Corrigendum

A correction is made to the article by Heymann et al. [(2014), IUCrJ, 1, 349–360].