Elemental X-ray properties   Atomic scattering factors   Compute X-ray absorption   Units conversion   Space group info   X-ray directory and information service   X-ray dynamical diffraction data on the web   X-ray anomalous scattering   X-ray properties of the elements   Bilbao crystallographic server (tools, space groups, data bases)   Space group frequencies   List of producers of X-ray Instrumentation + much more