Structural similarities among oxygen-deficient perovskites

A general review and description is given of vacancy patterns in oxygen-deficient perovskites A[sub m]B[sub m]O[sub 3m[minus]x]. Thirteen compounds that contain unique oxygen vacancy patterns and that adopt structures related to cubic closet packing are examined in detail: m = 2, x = 1, Ca[sub 2]Mn[sub 2]O[sub 5], LaSrCuGaO[sub 5], La[sub 2]Ni[sub 2]O[sub 5], LaSrCuAlO[sub 5], YBaCuFeO[sub 5], Ca[sub 2]Co[sub 2]O[sub 5]; m = 3, x = 1, 2, or 3, LaBa[sub 2]Cu[sub 2]TaO[sub 8], LaSr[sub 2]Fe[sub 3]O[sub 8], YBa[sub 2]Cu[sub 3]O[sub 7], LnSr[sub 2]Cu[sub 2]GaO[sub 7], YBa[sub 2]Cu[sub 3]O[sub 6]; m = 4, x = 1, Ba[sub 2]La[sub 2]Cu[sub 2]Sn[sub 2]O[sub 11] and Ca[sub 4]Ti[sub 2]Fe[sub 2]O[sub 11]. The structural similarity among the compounds is stressed by the presentation and examination of AO[sub 3[minus]x] slices. The influence of the A and B cations on the manner in which successive AO[sub 3[minus]x] layers are stacked is presented and discussed. 73 refs., 17 figs.