Jahn–Teller Lattice Distortions and Asymmetric Electron Density Distribution in the Structure of TmB12 Dodecaboride in the Temperature Range of 85–293 K

Abstract

The structure of single-crystal dodecaboride TmB₁₂, which possess metallic properties, has been studied by X-ray diffraction at nine temperatures in the range of 85–293 K. Jahn–Teller distortions of the cubic lattice are revealed. They are found to cause an asymmetric electron density distribution in crystal. Static components of atomic displacements are selected, and characteristic Einstein and Debye temperatures are determined for thulium and boron atoms, respectively. Temperature dependences of interatomic distances are obtained. The problem of localizing conduction electrons by means of X-ray diffraction analysis is stated.