Exploration of a new compound in the M–B–O–X (M: alkali metals; X: halogen) system: Preparation, crystal and electronic structures, and optical properties of Na3B6O10Br

A new bromoborate Na3B6O10Br has been synthesized by the high temperature solution method. It crystallizes in orthorhombic space group Pnma (No. 53) with lattice constants a = 12.780(8) Å, b = 9.914(6) Å, c = 7.518(2) Å, Z = 4. The crystal structure contains an infinite three-dimensional matrix that is built from B6O13 units, Na(1)O4Br2, Na(2)O6Br, and Na(3)O6 polyhedra. Interestingly, four B6O13 units are interconnected by oxygen atoms forming hexadecagon huge pores. IR spectrum, UV–Vis–NIR diffuse reflectance spectrum, and thermogravimetric analyses for the compound are also presented, as are band structures and density of states calculations.