Mineralogical Crystallography

Mineralogical Magazine

Tile crystal structures of sjogrenite and pyroaurite, two stacking modifications of approximate composition Mg.Fe.(OH),.(CO.).4H.O, have been determined by X-ray diffraction using three-dimensional methods. Sjogrenite is hexagonal, with a 3,13, C 15.66 A, space group P6.!mmc, Z = !; pyroaurite is rhombohedral, with aH 3,13, CH 23.49 A, space group R3m or R3m, Z = i. Both structures are based on...

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...

Chemical Crystallography

DNA Crystallography

Quantum crystallography.

Approximate wavefunctions can be improved by constraining them to reproduce observations derived from diffraction and scattering experiments. Conversely, charge density models, incorporating electron-density distributions, atomic positions and atomic motion, can be improved by supplementing diffraction experiments with quantum chemically calculated, tailor-made electron densities (form factors)...