Acta Crystallographica Section B

Structural Science

Volume 52, Part 6 (December 1996)

research papers

Acta Cryst. (1996). B52, 932-938 [ doi:10.1107/S0108768196008075 ]

Synthesis and structure refinement of a new type of layered intergrowth phase: Sb_3+xNb_3-xTiO₁₄ and Sb_3+xTa_3-xTiO₁₄

C. D. Ling, S. Schmid, J. G. Thompson, R. L. Withers and M. Sterns

Abstract: Attempts to synthesize Sb-based analogues of the known Bi-based Aurivillius phase, Bi₃TiNbO₉, have led to the discovery of an isomorphous pair of a new type of layered intergrowth phase of general stoichiometry Sb_3+xNb_3-xTiO₁₄ and Sb_3+xTa_3-xTiO₁₄. Electron diffraction proved essential for the initial recognition and structural characterization of these phases. The structures of Sb_3+xNb_3-xTiO₁₄, x = 0.89, and Sb_3+xTa_3-xTiO₁₄, x = 1.26, are reported. The structures are described as ordered intergrowths of -Sb₂O₄-type and Sb₂O₅-type structures, with Nb^V/Ta^V substituting for Sb^V in the former and Nb^V/Ta^V/Ti^IV substituting for Sb^V in the latter.