Ternary Suboxides Ti7Ga2O6, Ti3GaO, and Ti5Ga3O.

Single crystals of the new suboxides Ti7Ga2O6 and Ti3GaO were prepared using a Bi flux. Ti7Ga2O6 has a novel monoclinic crystal structure ( a = 17.3111(8) Å, b = 2.97660(10) Å, c = 7.2563(3) Å, β = 105.836(2)°, space group C2/ m), in which three O sites and one Ga site are separately coordinated by Ti atoms. Ti3GaO crystallizes in an orthorhombic cell ( a = 3.0952(2) Å, b = 10.6440(7) Å, c = 8.3206(5) Å, space group Cmcm) with a filled-Re3B type (anti-CaIrO3 type or antipost-perovskite type) structure. The electrical resistivities of a single crystal of Ti3GaO as measured in the c-axis direction were 1.6 × 10-6 Ωm at 300 K and 0.15 × 10-6 Ωm at 10 K. Single crystals of Ti5Ga3O x ( x = 1) with a filled-Mn5Si3 type structure (hexagonal, a = 7.5882(2) Å, c = 5.30170(10) Å, space group P63/ mcm) were also obtained.