ELECTRON DIFFRACTOMETRY AND CRYSTAL STRUCTURE OF BRUCITE. A. P. Zhukhlistov¹, A. S. Avilov², G. Ferraris³, B. B. Zvyagin¹, V. P. Plotnikov¹, ¹Inst. Ore Mineralogy RAS, ²Inst. Crystallography RAS, Moscow, Russia, ³University of Torino, Italy

The principles of direct measurements of the electron diffraction (ED) intensities developed in the State Optical Institute (St.Petersburg) and Institute of Crystallography RAS (Moscow) and a commercial EMR-102 ED-camera have been adapted for analysis of two-dimensional intensity distributions, in particular those of the most most informative oblique-texture patterns. With stationary detector, the ED-pattern is moved within electromagnetic fields with variable steps and along chosen directions. Special instrumental and software improvements provide corrections of different effects (e.g., incident beam instability) and increase precision, resolution, linearity and dynamic range of the measurements.

A set of intensities collected on brucite, Mg(OH)₂, showed that the described system of electron diffractometry is the most reliable ever produced for this purpose and opens new prospects in the field of structural crystallography by electron diffraction. In fact, it provides reliable Volt-values of the crystalline electrostatic potential field, whereas the structural features of brucite have been revealed with a precision comparable with that of X-ray diffraction for O and Mg atoms, and of neutron diffraction for the H atom.

Research supported by the Russian Foundation of Fundamental Studies.