Vibrational study of hydrogen beta alumina

Infrared absorption spectra of various samples of hydrogen beta alumina are discussed with respect to the alternative concerning the existence of hydroxyl (OH - ) and oxonium (H 3 O + ) ions in this compound. Some results of inelastic and quasi-elastic neutron scattering are also given. It can be shown that the presence of different entities depends on the method of preparation. In the case of silver beta alumina more or less reduced by hydrogen Al-O(5)-H + , Al-O(i)-H + , H 3 O + and H 2 O + , H 2 O species have been identified while hydrogen beta alumina prepared by treatment of the sodium derivative with sulphuric acid or by conversion of ammonium beta alumina does not contain any Al-O-H + groups attached to aluminium but contains oxonium ions or higher species. The existence of OH - ions in hydrogen beta alumina is very unlikely.