Crystallography of lepidolite

Redetermination of the Lepidolite-2m1 Structure

-The structure of a lepidolite-2Ml from Biskupice, Czechoslovakia, has been redetermined. Violations of systematic extinctions and of monoclinic equivalences plus the results of a second harmonic generation test indicate that the true symmetry most likely is C]'. The deviation of the data set from C2/c symmetry, however, proved to be too small to permit a statistically significant refinement in...

Incommensurate Crystallography

Acta Crystallographica Section A: Foundations of Crystallography covers theoretical and fundamental aspects of the structure of matter. The journal is the prime forum for research in diffraction physics and the theory of crystallographic structure determination by diffraction methods using X-rays, neutrons and electrons. The structures include periodic and aperiodic crystals, and non-periodic d...

Crystallography of Icosahedral Crystals

The crystallography of icosahedral crystals is constructed. The actual three-dimensional crystal is represented by a three-dimensional cut in a regular six-dimensional periodic crystal with symmetry described by a six-dimensional space group, and the positions of atoms correspond to an arrangement of hypersurface segments. The resulting crystal can not in general be viewed as a space-filling ar...

Crystallography of Dodecagonal Quasicrystals

A detailed model structure of dodecagonal quasicrystals is proposed which applies to both dodecagonal Ni-Cr and V-Ni or V-Si-Ni. This model structure can be represented as the restriction of a 5d periodic structure to a 3d subspace, which is identified with physical space. The point group and the space group of the 5d periodic structure are determined. The latter is non-symmorphic, containing a...

Chemical Crystallography