issue contents

ISSN: 2053-2733

November 2005 issue

Highlighted illustration

Cover illustration: An experimentally derived plot of the Fermi hole mobility function (FHMF) for urea. The FHMF can be interpreted as a potential energy surface for electron transfer. This plot was obtained from a Hartree-Fock wavefunction constrained to fit measured X-ray diffraction structure factors, using the Tonto program. See Jayatilaka & Grimwood [Acta Cryst. (2004), A60, 111-119].

research papers

link to html
Electron nanodiffraction and high-resolution imaging evidence is presented to support a new structural form of multiwall boron nitride nanotubes that consist of two helices; one is highly crystalline and faceted and the other is circular and less ordered.

link to html
A new method is presented which decides algorithmically whether a combinatorial space tiling is realizable in Euclidean space or in other homogeneous geometries.

link to html
A method for the determination of anomalous scattering factors very near to an absorption edge is proposed using their semicircular behavior. As an example, Ge anomalous scattering factors are determined, which show excellent agreement with the values determined by two other methods.

link to html
Ultra-small-angle X-ray scattering data were obtained from deformed single-crystal aluminium samples. These data are consistent with recent theoretical predictions of scattering from dislocation walls, allowing quantitative microstructural parameters to be extracted.

link to html
A theoretical foundation and test-case evaluation is presented for de novo structure determination using f′ difference techniques. Prospects for extension of these methods to larger molecules than are currently tackled, including proteins, and the possible use of softer X-rays are discussed.

link to html
The proposed crystalline phase identifier consists of a number of components (layers) describing enough properties of the phase to allow a unique identification. These layers consist of the chemical formula, a flag indicating the state of matter, the space-group number and the Wyckoff sequence. They are defined in such a way that they can be incorporated into the IUPAC International Chemical Identifier (InChI) proposed by the International Union of Pure and Applied Chemistry (IUPAC).

short communications

link to html
The symmetry point group statistics for all combinatorially non-isomorphic convex 12-hedra (6384634 in total) are contributed in the paper. The numbers of 12-hedra with 11 to 19 vertices are revised.

link to html
A constructive proof of the Motzkin–Grünbaum theorem (at least one fullerene Cn with any even n ≥ 24 exists) is suggested

international union of crystallography

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