Structure of the Hydrogen-Bonded Water Molecule in Crystals

Abstract

A correlation of the structural data on 15 hydrates obtained by x-ray diffraction, neutron diffraction, and proton magnetic resonance reveals that when a water molecule is hydrogen bonded into a crystal structure and the angle subtended at the donor water oxygen by the acceptor atoms deviates from the vapor H–O–H angle, bent hydrogen bonds are formed in preference to distortion of the H–O–H angle. Theoretical justification for this result is obtained from energy considerations by calculating the energy of formation of bent hydrogen bonds on the basis of the Lippincott—Schroeder potential function model for the hydrogen bond and the energy of deformation of the H–O–H angle from spectroscopic force constants.