A strontium aluminium antimony oxide with Kagome layers: Sr_(1.5 + x)Sb_(2 - x)~(5+)Al_(5 + x)O_(14) (x approx = 0.21)

摘要

The Sr_(1.5 + x)Sb_(2 - x)Al_(5 + x)O_(14) (x approx = 0.21) phase has been isolated by solid state reaction and characterized by single crystal X-ray diffraction. It crystallizes in the R3-bar m (no. 166) space group with a = b = 5.611(4) A and c = 27.36(2) A. Its structure consists of Kagome layers made of AlO_6 octahedra sandwiched between two mixed layers, made of corner sharing (Sb_(1 - x/2)Al_(x/2))O_6 and AlO_4 polyhedra. The connection between two successive mixed layers is ensured by a double layer of Sr~(2+) ions. The present oxide is compared to the A_(1.5 + x)SbAl_5O_(11.5) oxides (A = Sr, Ba) formed by similar Kagome, mixed and A~(2+) layers.