A review is given on recent X-ray, neutron diffraction and nuclear magnetic resonance studies of inorganic hydrates. The geometry of water molecules and the interaction with their surroundings are discussed in terms of hydrogen bonding between donors and acceptors and lone pair coordinations to metal cations. Various types of finite or infinite hydrogen bonded water networks are related to their characteristic features. Among these, the static and dynamical structures of hydrogen bonded water layers in tin (II) chloride dihydrate are described in some detail, where the hydrogen atoms play an important role in its phase transition. The molecular motion of water in some f erroelectric hydrates and the static and dynamic structure of hydrated protons are also included in this survey.
