The title compound, more succinctly referred to as HMT-hydrate, is a rare example of a water-framework zeolite structure with an organic guest molecule hydrogen bonded to the walls of the channels. HMT almost certainly occurs in cometary ices and is consequently likely to have been accreted into icy satellites early in solar system history. It is also likely to form high in Titan's atmosphere and accumulate as a sediment on the surface. In either situation, HMT has the opportunity to interact with liquid and form the hexahydrate crystal. Where it exists in the deep interior of large icy moons it may experience pressures of several GPa. There have been very few studies of this material, and none at high pressure. The objective of this proposal is study the phase behaviour and determine the incompressibility of HMT-hydrate up to 5 GPa using the Paris-Edinburgh cell on PEARL/HiPr.