Abstract A simplified description of complex structures is proposed. The method consists in defining a geometrical unit of polyhedra, called UGP. Then, a three-dimensional network is built up from simple stackings of these UGP. Cationic sites and additional anionic sites are generated from the stacking of UGP. An explicit formulation “counterions[network]additional ions” summarizes the structure description. This method is applied to numerous structures that involve square antiprisms and can be used for other polyhedra.