Abstract: | On Oxotitanates of the Alkaline Metals: On Na4Ti5O12 Colourless single crystals of the new titanate Na4Ti5O12 (starting from mixtures Na2O/TiO2, 1000°C, 6 d, Au-crucible, open system) crystallize in the monoclinic system, space group C2/m, a = 26.544(9), b = 2.952(1), c = 6.322(3) Å, β = 95.79(3)°, Z = 2, drö = 3.45 and dpyk = 3.38 g · cm?3 (four-cycle-diffractometer data, PW 1100, 2?-scan, MoKα). R = 5.09% and Rw = 4.87% for 1178 independent I0(hkl) with 3° ≤ 2? ≤ 34°. Corrugated layers of Ti5O12, held together by Na+, are stacked along 001]. Details about partially occupied positions of Na+, Effective Coordination Numbers (ECoN), the Madelung part of lattice energy (MAPLE), and the structural differences to Na2Ti3O7 are discussed. |