Useful Links
Structure visualisation
external pageVestacall_made is a powerful free of charge structure visualisation program. Most useful for inorganic structures.
external pageMercurycall_made is a commercial structure visualisation program distributed by CCDC. The free version has reduced functionality, but is still very powerful. Most useful for organic structures.
external pageCrystalMakercall_made is a commercial visualisation program with a lot of add-ons. Most useful for inorganic structures.
Single crystal structure refinement
external pageShelxcall_made is THE standard for single crystal structure refinements.
external pageOlexcall_made provides a nice interface to shelx and offers a lot of additional tools for visualisation and more. Free of charge software with some commercial add-ons. Highly recommended for organic structure refinement.
external pageJanacall_made is the best choice for modulated structure refinements and other non-standard average structure refinements (neutrons, electrons, magnetic structures, etc.).
Powder diffraction
Widely used and free software for Rietveld refinement and other powder diffraction data evaluation are external pageFullprofcall_made and external pageGSAScall_made
The most popular commercial powder diffraction programs are external pageTopascall_made and external pageHighscore Pluscall_made