The proposing team has recently obtained important neutron scattering results on samples containing molecular hydrogen (sII and sH hydrogen-filled clathrate hydrates), measured on TOSCA, disclosing the quantum dynamics of the guest H2 molecules inside the host cages. This proposal aims to study HD in the new compound (named C0 “filled ice”) still formed by molecular hydrogen and water, but having a totally different crystal structure, analogous to that of alpha-quartz. This system, due to its high hydrogen content, might have a relevance for hydrogen storage applications. The molecular cross section of HD, in contrast to that of para-H2, is such that both the rattling and rotational bands will appear with marked intensity in the spectrum.