In an effort to further our understanding of the hydride dynamics we acquired additional static shifting d-echo spectra of BTOD CA (see Fig. ) at a very low (100 K) and high temperature (420 K). However, no significant changes are observed in the quadrupolar spectra (see Fig. ) nor the 2D spectra (see Fig. ), which suggest either complete absence of any dynamics or dynamic processes that occur in the slow exchange regime, or otherwise do not average the quadrupolar interaction parameters over the entire temperature range 100 420 K. Fig. (b) displays the low-temperature nearest-neighbour hopping mechanism proposed by QENS, in which the EFG tensor orientation rotates with each hydride ion jumps to the nearest oxygen vacancy and we expect to observe averaged tensor parameters experimentally. Assuming a random walk diffusion model (see Fig. ) we predict that the occupation probability of all six the coordination positions of the Ti ion to be equal. According to this model the experimentally observed EFG would be the average over the six available hydride positions. The simulated spectrum of the averaged tensor for the single occupied bandstate is given in Fig. ) showing a single sharp peak. The observed experimental spectrum is clearly distinct from the simulation and suggests that at room-temperature hydride ions do not diffuse freely through the entire material on the ps-ns timescale via the nearest-neighbour hopping mechanism. Fig. (c) shows the high-temperature next-nearest-neighbour hopping mechanism proposed by QENS, which does not lead to a change in the EFG tensor orientation with vertical or horizontal hydride ion jumps to next-nearest oxygen vacancies. As a consequence, the EFG tensor is not averaged and the quadrupolar spectrum (see Fig. ) predicted by DFT is not altered, which matches the experiment (see Fig. ). Therefore, either hydride ions predominantly hop to the next-nearest oxygen vacancy throughout the studied temperature range (100 420 K) or the low-temperature mechanism takes place on a drastically slower Interestingly, a recent DFT investigation on these materials indicated that the configuration with oxygen vacancies located in the next-nearest position to the hydride ion exhibits the lowest energy, thus is the most stable. Possibly, this ion arrangement dominates within the oxyhydride structure, therefore hydride ion diffusion occurs exclusively via the next-nearest-neighbour hopping mechanism.