This proposal requests 7 days of beamtime on the quasielastic neutron scattering spectrometer OSIRIS to investigate the mechanism of hydride ion mobility in the recently discovered LaxSr4-xNiRuO4H4 (x = 0.5, 1, and 1.5) oxide-hydride phases. Ionic conductivity lays at the heart of the function of many technological devices, such as batteries and fuel cells, to name a few. Thus, besides being of considerable fundamental interests, these new materials are as well of technological relevances. The specific aims are to determine the time-scale and geometry of hydride ion dynamics, how it depends on temperature and on composition (x), relate to the dynamical nature of hydride ions in other oxide-hydride phases, and (with time) develop a generic understanding of H dynamics in oxides, stretching from hydridic to protic species.