An α-rhombohedral boron-related compound with sulfur: Synthesis, structure and thermoelectric properties

The structural and thermoelectric properties of a series of icosahedral boron-rich solids, B6S1 − x obtained from the elements in a Ga melt were studied to estimate their potential as thermoelectric materials. Rietveld analysis of synchrotron and conventional X-ray powder data displayed the rhombohedral structure with the α-rhombohedral boron framework of B12 icosahedra and a narrow filling fraction range for sulfur atoms in the interstitial voids (0.37 < x ⩽ 0.40). The samples obtained exhibited p-type semiconducting behavior with large Seebeck coefficients, reaching a maximum of ∼220 μV K−1.