FOX is a program for the ab initio structure determination from powder diffraction (neutrons, X-Ray). The crystal structure can be described as any combination of atoms, molecules or polyhedra, without a priori information about the connectivity of these 'building block'. Fox can make multi-pattern global optimizations, and automatically correct special positions.

FOX could also be used for educational purposes, to display Crystal Structures in 3D with the associated powder diffraction pattern.