Neutron powder diffraction will be used to determine hydrogen (deuterium) positions and occupational parameters in novel metal hydrides (deuterides) at ambient conditions. Zintl phase hydrides exhibit fascinating bonding properties and are interesting for hydrogen storage media. Details of the crystal structure of the deuteride of LaGa2, especially concerning deuterium ordering, will be solved and the crystal structure refined by the Rietveld technique. This will clarify the bonding situation (Ga-D bonds) and allow finalizing the crystal structure refinement for LaGaDx, where LaGa2Dy was found as a secondary phase. Metal hydride oxide have a high potential as functional materials, e. g. for luminescence applications. Neutron powder diffraction data will allow the location of hydrogen (deuterium) positions in the novel hydride oxide YHO (YDO). In this case, the hydride will be used in addition to the deuteride in order to increase the scattering contrast between hydrogen and oxygen.