Plate and needle-like crystal structure determination by combining electron and synchrotron diffraction

Abstract

In recent years, significant progress in determining light-element crystal structures using electron diffraction has been made to meet the increasing needs from the material science community. The set of techniques for carrying out electron crystallography, including sample preparation, data collection and recording, diffraction micrograph digitization, and confirmation by direct phasing methods and structure refinements, have being developed. However, only a very limited number of structures have been determinated by electron crystallography because of a number of severe problems and difficulties. Meanwhile, the progress in determining crystal structures using x-ray diffraction has been rapidly increasing, particularly because of the more extensive use of powerful synchrotron diffraction techniques. In this case, the minimum crystal size required for a single-crystal study has decreased from 100 microns to about 10 microns. Even so, many new materials can only be obtained in microcrystalline form with crystallite sizes well below one micron. In this submicron regime, ab initio structure solutions from synchrotron powder-diffraction patterns have proven to be quite powerful.