La0.8Ba1.2GaO3.9 center dot nH(2)O presents an interesting system with tetrahedral network of GaO4, and high oxide ion and proton conductivities. High-resolution quasielastic incoherent neutron scattering experiments were performed to gain better understanding of the proton conduction mechanism in tetrahedral systems. Translational long-range proton diffusion was observed. The activation energy for this process is 0.5 eV. Mean-square-displacement of 0.7 A(2) for protons was obtained for the temperature range where the long-range proton diffusion occurs. (C) 2013 Elsevier B.V. All rights reserved.