The layered cuprates are analyzed in the fragment approximation. The s
tructures of cuprates are considered as alternating stacks of minals a
nd blocking layers. Minals represent the eu-containing structural unit
s which are constant in a series of related structures. The structural
changes, which occur under substitution of basic elements in the cati
on sublattice, are analyzed in the proposed classification scheme. (C)
1997 Academic Press Limited.