Lattice disorder and physical properties connected with the hydrogen arrangement in ice crystals

The present knowledge of the hydrogen positions and of the physical properties sensitive to the hydrogen arrangement in ice crystals is reviewed. All possibilities of configurational changes in the ideal and the real crystal are considered. It is shown that the observed time-independence of the ionic conductivity leads to the conclusion that ions (H3O+ and OH-) and Bjerrum defects (doubly-occupied and vacant bonds) must be present simultaneously. The concept that the hydrogen configurations are changed only by the diffusion of such defects proved to be the basis for a consistent theoretical explanation of the electrical, mechanical and nuclear relaxation phenomena and of the thermal properties.