A novel Li-based spinel compound with the composition of MgLi2/3Ti4/3O4 was synthesized by the conventional solid-state reaction method. The phase structure was studied by X-ray diffraction (XRD) technique. When the calcination temperature was over 1050 degrees C, a single phase compound which has a cubic structure [Fd-3m (227)] with cell parameters of a = 8.4057 angstrom, V = 593.91 angstrom(3), rho = 3.51 g cm(-3) and Z = 8 was obtained. MgLi2/3Ti4/3O4 ceramic could be well densified after sintering above 1125 degrees C. The microwave dielectric properties were measured using a microwave vector network analyzer in the frequency range of 7-9 GHz MgLi2/3Ti4/3O4 ceramic sintered at 1125 degrees C for 2 h showed microwave dielectric properties of epsilon(r) = 20.2, Q x f = 62,300 GHz, and tau(f) = -27.1 ppm degrees C-1. Furthermore, 0.95MgLi(2/3)Ti(4/3)O(4)-0.05CaTiO(3) ceramic sintered at 1200 degrees C for 2 h exhibited good properties of epsilon(r) = 22.6, Q x f = 48,000 GHz, and tau(f) = -2.3 ppm degrees C-1. (C) 2012 Elsevier B.V. All rights reserved.