“Ab-initio” structure solution of nano-crystalline minerals and synthetic materials by automated electron tomography

Most of the newly discovered mineral phases, as well as many new synthesized industrial materials, appear only in the form of nano crystals, with a size not sufficient for single-crystal x-ray structure analysis. The development of techniques able to investigate the structure of nano crystalline materials is therefore one of the most important frontiers of crystallography. The most widespread technique providing relatively fast and well consolidated routes for structure analysis of bulk materials is x-ray powder diffraction (XRPD). Nevertheless, XRPD suffers from intrinsic 1-dimension reduction of information that greatly limits its applicability in presence of peak broadening and overlapping. Peak broadening is usually caused by very small crystallites, namely less than 50nm. Overlapping of peaks is problematic mainly for intensity integration, but in case of polyphasic mixtures or significant amount of impurities it can be critical also for cell parameter determination and reflection indexing. © 2012 Springer-Verlag Berlin Heidelberg. All rights are reserved.