The exploration of the Li-Ti-Mg-O system, using both sol-gel technique and solid state reaction method, allowed a new phase, Li2MgTiO4, with disordered rock salt structure (a = 4.159 angstrom) to be synthesized. The latter is shown to be a good type I dielectric material, with a relative constant of 15 at high frequency and low dielectric loss (tan delta < 10(-3)) over the temperature range -60 to 160 degrees C. It is also observed that the sintering temperature of this phase is strongly lowered by adopting the sol-gel technique compared to solid state reaction (1150 degrees C instead of 1300 degrees C). Finally we show that this phase exhibits cationic conductivity above 400 degrees C (sigma(600 degrees C) = 9 x 10(-5) S cm(-1)). (C) 2006 Elsevier Ltd. All rights reserved.