In this paper the synthesis and conductivities of the garnet-related Li ion conductors, Li(5)Ln(3)Sb(2)O(12) (Ln = La, Pr, Nd, Sm, Eu), are reported. These phases show high Li ion conductivity, similar to previously reported for the related Li5La3M2O12 (M=Nb, Ta) materials. Neutron diffraction structural studies are also reported for Li5La3Sb2O12 indicating a cubic unit cell, space group Ia-3d, with Li located in two partially occupied sites. (c) 2008 Elsevier B.V. All rights reserved.