High-pressure synthesis of boron-rich chalcogenides B12S and B12Se

Two boron-rich chalcogenides B12S and B12Se isostructural to α-rhombohedral boron were synthesized by chemical reaction of the elements at high-pressure – high-temperature conditions. The crystal structures stoichiometries both compounds confirmed Rietveld refinement synchrotron X-ray diffraction data elemental analysis. experimental Raman spectra investigated for first time. All observed bands have been attributed theoretically calculated phonon modes, mode assignment has performed.