Self-Hosting Incommensurate Structure of Barium IV

Abstract

The structure of phase IV of barium has been solved from single-crystal and powder diffraction x-ray data. It is composed of a tetragonal ``host,'' with ``guest'' chains in channels along the $c$ axis of the host. These chains form two different structures, one well crystallized and the other highly disordered and giving rise to strong diffuse scattering. The guest structures are incommensurate with the host.