Salt-flux Synthesis, Crystal Structure and Theoretical Characterization of Rb0.74Ga6.62Ti0.38O11

Abstract Single crystals of Rb0.74Ga6.62Ti0.38O11 (RGTO) were grown from a mixed RbCl-RbF flux at 850 °C. The compound crystallizes in the RbGa7O11 structure type, which is reminiscent of the hollandite and β-Ga2O3 structure types. RGTO crystallizes in the monoclinic space group P2/m with lattice parameters a = 8.3355(8) A, b = 3.0286(3) A, c = 9.5028(9) A, and β = 114.620(3)°. The crystal structure of RGTO is comprised of GaO6 and mixed (Ga/Ti)O6 octahedra and GaO4 tetrahedra connected in a complex three-dimensional, anionic framework exhibiting eight-sided channels that are occupied by disordered Rb cations required for charge balance. First-principles calculations in the form of density functional theory were performed, which indicated the complex to be a charge transfer semiconductor.