High-Pressure Synthesis, Structure, and Electrical Property of Iodine-Filled Skutterudite I0.9Rh4Sb12-First Anion-Filled Skutterudite

An iodine containing skutterudite compound I0.9Rh4Sb12 wits prepared by the reaction of the element mixture with an iodine excess composition (I:Rh:Sb = 1.5:4:12) at 5-12 GPa and 850 degrees C. Rietveld structural analysis revealed that this is the first anion-filled skutterudite crystallizing in the space group I m-3 with it lattice constant of a = 9.29997(6) angstrom. X-ray photoelectron spectroscopy proved the oxidation state of iodine to be I-. The compound is semimetallic with a resistivity of 9.9 m Omega cm at 300 K. Band structure and density of states calculations Suggested that the bands near the Fermi level are mainly composed of Rh-p, Rh-d, and Sb-p orbitals; the contribution of iodine is not large.