Structure and thermal properties associated with some hydrogen bonds in crystals, II. Thermal expansion

Abstract

One of the most important thermodynamic properties of a crystal in relation to its structure is the thermal expansion, which provides information on the lattice vibrations, and thus indirectly on the binding forces. The experiments described in this paper were carried out with a view to obtaining fresh information on hydrogen and hydroxyl bonds in crystals from measurements of the thermal expansion. A comparison of the thermal expansion of corresponding- hydrogen and deuterium compounds from about 90° K to room temperature was made in order to distinguish between lattice deformations due to zero point energy and thermal energy respectively. The marked anisotropy of thermal expansion in crystals containing hydrogen bonds throws interesting light on the structure.