X-ray powder diffraction

X-ray powder diffraction is the most important technique for the structural characterization of solids. Routinely applied to phase analysis and the refinement of crystal structures the advent of high brilliance synchrotron sources and improvements of detectors and computers brought a new quality to the field which reflected back to laboratory use. By the introduction of established methods for the solution of structures (Patterson, Fourier or direct methods) many crystal structures were determined from powder patterns. Examples are given for organic molecules and ternary oxides. Furthermore time and temperature resolved studies gave information on phase transitions and kinetics. With synchrotron radiation powder pattern were collected in a temperature and pressure range which corresponds to conditions in the interior of the earth and were succesfully refined.