The structural phase transitions and electrical properties of Ti30,, the pseudobrookite series Li ,Ti ,-,O, and MgxTi3-,0,, and of v305 structure type CrTi,05 have been studied by high-temperature X-ray diffraction, differential scanning calorimetry, and d.c. conductivity measurements. Ti30, undergoes a complex transformation between 440 and 515 K from semiconducting a-Ti305 to metal-like P'-Ti305 with orthorhombic pseudobrookite structure. The intermediate formation of the monoclinic /?-Ti,O, polymorph involves a martensitic transition at 467 K. The following continuous 8to P'-type transition is accompanied by a small polaron order-disorder process. In the series Li ,Ti ,-,O, and MgxTi,_,O, the pseudobrookite-related phases are stabilised. Electrical conductivities are as high as 170 S cm-' at 1073 K for CrTi ,O,. The materials of the Mg,Ti3-x05 series and CrTi,O, are promising candidates for anodes in solid-oxide fuel cells.