On the Crystal Structure of Bi₂Te₄O₁₁

Abstract

Bi₂Te₄O₁₁ is monoclinic, space group P2₁/n; the lattice parameters derived from a Guinier powder pattern ( Si standard) are: a = 6.9909(3), b = 7.9593(3), c = 18.8963(8) Å , β = 95.176(3)º, Z = 4, V = 1047.15 Å. The structure was solved independently from both single-crystal X-ray data and a combination of X-ray and neutron powder data. It is an anion-deficient superstructure of fluorite in which can be recognized the ordered intergrowth of fluorite-type Bi₂Te₂O₇ and rutile-type Te₂O₄. Lone-pair electrons are stereochemically active.