Structural Classification of Perovskites ‚ Hierarchy

Structural variants rise from different stacking sequences of close-packes AX₃-layers. The general formula of these stycking polytypes is

A_mB_nX_3m (with n <= m)

Stoichiometric ABX₃-perovskites show following stacking sequences

c-Stacking (1.1)
hcc-Stacking (4.1)
hc-Stacking (4.2)
hhc-Stacking (4.3)
h-Stacking (4.4)

A similar sequence is found in cation-deficient perovskites, e.g. A₃B₂X₉. The pure cubic stacking is described in 2.4.3.

Adapted from "Hierarchies of perovskite-like crystals" by K. S. Aleksandrow and V. V. Beznosikov in Physics of the Solid State 39, 695-715 (1997).