NEW REDUCED TERNARY TITANATES FROM BORATE FLUXES

Single crystals of the new reduced strontium titanate SrTi11O20 (space group P1, a = 7.1252(8) Å, b = 7.6644(8) Å, c = 13.1577(16) Å, α = 90.21(1)°, β = 92.79(1)°, γ = 103.94(1)°) are formed by slowly cooling SrTiO2.5 in molten SrO · 2B2O3 flux in high vacuum. The compound crystallizes in a new structure type based on sheared double and single rutile chains of TiO6 octahedra. Formation of a new monoclinically distorted reduced Ti-hollandite, La1.33Ti8O16 (space group I2 m, a = 9.946(2) Å, b = 2.9668(4) Å, c = 10.280(2) Å, β = 91.09(2)°), was observed upon dissolving LaTiO3 in a molten La2O3 · 3B2O3 flux. The crystal structures of both compounds were determined by single crystal X-ray diffraction. © 1991.