Ising-type analysis of superconducting cuprates shows that the layered structures are composed of perovskite, SrO and structural units with different interactions between oxygen atoms. The 45 structures for a combination of a maximum of eight structural units can be classified into 13 structural families which are named after the authors who synthesized the first compound or found superconducting properties, e.g. the Ruddlesden-Popper, Müller-Bednorz family with the sequence of coordination numbers (CN) of metal atoms . The number of layers is reduced if segregation, for example of a perovskite with CN 12 6 or of SrO with 6 coordination, is considered. Other compounds such as of the Lucas, Raveau series with the CN sequence occur only in a few cases because of a similar composition and lower stability. Another five structural families are obtained if the structural unit (4 8) is replaced by or if SrO is replaced by in the Aurivillius family.