Acta Crystallographica Section B

Structural Science

Volume 56, Part 4 (August 2000)

research papers

Acta Cryst. (2000). B56, 594-600 [ doi:10.1107/S0108768100003906 ]

Electron density and atomic displacements in KTaO₃

E. A. Zhurova, Y. Ivanov, V. Zavodnik and V. Tsirelson

Abstract: The atomic interactions and anharmonicity of atomic displacements in the virtual ferroelectric KTaO₃, potassium tantalate, have been studied using accurate single-crystal X-ray diffraction at room temperature. The multipole analysis of electron density and Gram-Charlier series description of anharmonic atomic displacements allowed us to perform a quantitative analysis of the chemical bonding and atomic motion in this crystal. Closed-shell interactions between Ta-O and K-O pairs of atoms were found, while no interaction was observed for the Ta-K and O-O atomic pairs. The character of the anharmonic atomic displacements is discussed and compared with those in SrTiO₃.

Keywords: Electron density; Atomic displacement; Anharmonicity; Ferroelectric.