NaBSiSe: a novel B-cluster-containing quaternary selenoborate framework material.

We report the successful synthesis of the new quaternary, three-dimensional NaSiBSe material using a solid-state synthesis route. This compound is characterized by a unique framework structure that features the rare icosahedral [B] cation which is connected SiSe polyhedral units into a 3D framework structure with Na ions located inside the channels. The NaSiBSe compound crystallizes in the cubic crystal system in the space group 3̄, with lattice parameter = 11.91110(10) Å and unit cell volume of 1689.88(4) Å. The 3D framework of the [SiBSe] anion contains B icosahedra with six of their edges bridged by tetrahedral SiSe groups. The B icosahedral units are connected by the SiSe tetrahedral units which bridge between each B icosahedron. Ultraviolet-Visible (UV-vis) spectroscopy revealed that NaSiBSe exhibits semiconducting behavior with an estimated bandgap of 2.1(1) eV. powder X-ray diffraction (PXRD) studies were conducted to investigate the phase formation of this compound as a function of temperature to obtain information of its thermal stability and structural evolution.