Architecture of crystal structures from square planes

The crystal structures of ordered b.c.c. (body-centered cubic), f.c.c. (face-centered cubic) or primitive cubic alloys and related NaCl, ZnS or CaF derivative structures are characterized by the self-coordination numbers , of the A atoms with A atoms. Structures with identical and values for all A atoms are at the corners of and structure maps, and can be analyzed for attractive or repulsive interactions of A atoms. Most observed structures are at the borders of the structure map and can be obtained by ∼10 different combinations of structural units. The different combination mechanisms explain e.g. the shear structures of CuAu II or and the occurrence of vacancies in NaCl-related structures like NbO.