H and 2 H solid-state NMR Here we are interested in examining the electronic structure of barium titanium oxyhydride (BTOH) in order to understand if the additional electrons introduced in the reduction process form electron polarons (Fig. ) or delocalized bandstates (Fig. ) and 1(c)). Furthermore, we address whether the bandstate constitutes hydride sites with a single or double occupancy as shown in Fig. ) and 1(c).