The proposing team has a well established experience in the use of INS on samples containing H_2. Our recent experimental results on sII and sH H_2-filled clathrate hydrates, obtained on TOSCA, allowed to investigate the quantum dynamics of the guest H_2 molecules inside the host cages. This proposal aims to study a new compound (named C_0 ¿filled ice¿) still formed by H_2 and H_2O, but having a totally different crystal structure, analogous to that of alpha-quartz. This system might have a relevance from the perspective of new materials suitable for H_2 storage applications, since it can contain a large amount of H_2. From the neutron spectra it will be possible to derive the different dynamics of the molecules inside the C_0 cavities, which have a distinct geometry with respect of those of sII and sH clathrates, as well as to extract the H-projected density of phonon states of the host