Cover illustration: Electrostatic equilibrium of simultaneous Coulomb attraction and core repulsion for an ensemble ; the conjoint centroids, shown in yellow, characterize force-free positions of the fragment inside the unit cell. For comparison, the pure Coulomb equilibrium is shown in the background. See Mädler, Behrends & Knorr [Acta Cryst. (2001). A57, 20-23].
A general method for determining subgroups of any group is explained. Application to crystal family holohedries of 5D space permits the 955 point groups in this space belonging to 32 crystal families to be found.
Basic principles for the Weigel–Phan–Veysseyre system of crystallographic point groups of any dimensional space are explained. As an application, the 196 point groups belonging to 15 crystal families are given a WPV symbol.
Topologies of total charge densities obtained from crystalline molecular-orbital calculations are compared to those obtained from the multipole refinement of the structure factors obtained from the same densities.
The feasibility of building a database of theoretical atomic deformation density parameters applicable to the construction of the densities of biomacromolecules and to the interpretation of their X-ray diffraction data is discussed.
Intensity profiles measured with synchrotron radiation are compared with theoretical intensity distributions. Expressions for the integral width as well as the full width at half-maximum are presented.
The substitution of boron atoms for copper was studied by combining high-resolution electron microscopy (HREM) and electron diffraction. The boron atoms were determined to be located at the `chain' Cu sites.
A revised proof is given that the root-mean-square deviation between more than two vector sets after optimal superposition induces a metric. This corrects an error in a previous manuscript [Kaindl & Steipe (1997>). Acta Cryst. A53, 809].