Synthons and design in metal phosphates and oxalates with open architectures

The fascinating three-dimensional architectures of metal phosphates and related materials are shown to be formed by a progressive building-up process, starting from low-dimensional structures. Accordingly, the zero- and one-dimensional structures act as synthons in the formation of these structures.

Structure of Nd₁₀W₂₂O₈₁ from high-resolution electron microscopy and X-ray powder diffraction

The crystal structure of Nd₁₀W₂₂O₈₁ has been determined, using a combination of high-resolution transmission electron microscopy and X-ray powder diffraction methods. Nd₁₀W₂₂O₈₁ is a new type of pentagonal column (PC) structure.

High-pressure structures of α- and δ-ZrMo₂O₈

The structure of the monoclinic high-pressure phase δ-ZrMo₂O₈ has been solved by direct methods and refined using high-pressure synchrotron X-ray powder diffraction data. Rietveld refinements of the α- and δ-phase from 0.2 to 1.9 GPa have been performed.

Kinetic behaviour investigations and crystal structure of nitric acid dihydrate

The kinetic behaviour of nitric acid dihydrate, HNO₃·2H₂O, proves its possible crystallization. From a single crystal the molecular and crystal structures have been determined, revealing a two-dimensional hydrogen-bond network, and molecular arrangement intermediate between those of the monohydrate and the trihydrate of nitric acid.

Structure of manganese di­acetate tetrahydrate and low-temperature methyl-group dynamics

The crystal structure of manganese diacetate tetrahydrate has been determined by single-crystal neutron diffraction. A quantum model is proposed to account for the observed proton density distributions and the rotational dynamics of methyl groups observed by inelastic neutron scattering.

Structures of three cis-β₁ and three cis-β₂ isomers of [Co(trien)(aminoacidato)]²⁺ complexes

The crystal structures and absolute configurations of three cis-β₁ and three cis-β₂ isomers of [Co(trien)(L-aminoacidato)]²⁺ are reported, as are their crystallization behavior and packing features.

X-ray investigations of sulfur-containing fungicides. II. Intramolecular forces governing the conformation of four novel α-phenylazo- and α-phenylhydrazono-β-keto­sulfones

The title compounds represent a new group of fungicides characterized by substantial photodynamic activity. Their conformation is controlled by stereoelectronic interactions which help to reduce the large electron-withdrawing capacity of the sulfonyl group. Additionally, strong intramolecular resonance-assisted hydrogen bonds between the sulfonyl and α-phenylhydrazono groups exist in two of the compounds investigated. The strength of these bonds and the stereoelectronic back-donation are mutually related.

Synthesis and structure of, and bonding in some derivatives of 2,6,9,10-tetraoxatri­cyclo[3.3.1.1^3,8]decane

The structures of five members of a new class of compounds have been determined by X-ray diffraction. Comparison of the measured bond lengths with their quantum chemically calculated counterparts might lead to erroneous conclusions if correlation energy is omitted from the calculations.

Structural studies on C-amidated amino acids and peptides: structures of hydrochloride salts of C-amidated Ile, Val, Thr, Ser, Met, Trp, Gln and Arg, and comparison with their C-unamidated counterparts

To elucidate the structural features caused by C-amidation of amino acids, the crystal structures of HCl salts of C-amidated Ile, Val, Thr, Ser, Met, Trp, Gln and Arg have been analysed and compared with those of the corresponding amino acids. The Cα—H⋯O hydrogen bonds, intermolecular carbonyl–carbonyl interactions and the interaction patterns with Cl ions could be considered as structural features which differentiate both molecules from each other.

Structures of tetra­thiabenzo­quinone derivatives and the order–disorder phase transition

The crystal structures of two tetrathiabenzoquinone derivatives were found to form characteristic one-dimensional molecular columns and two-dimensional or quasi two-dimensional molecular sheets.

Automatic detection of molecular symmetry in the Cambridge Structural Database

A program to detect molecular symmetry in selected crystal structures from the Cambridge Structural Database is reported, plus an implementation of the display of symmetry elements.

Ethane-1,2-di­phosphonic acid as a building block in supramolecular chemistry; a pillared-layer framework and framework-encapsulated cations

Organic salts formed between ethane-1,2-diphosphonic acid and the diamines piperazine and 4,4′-trimethylenedipiperidine are both characterized by richly complex intermolecular hydrogen bonding, giving two different three-dimensional framework structures.

Competition of hydrogen-bond acceptors for the strong carboxyl donor

Database study on the competitive effects involving the carboxyl group. A correlation between the success in competition and the average hydrogen-bond distance is established.

Notes for Authors

Modern crystallography Vol. 2. Structure of Crystals.