Infrared studies of hydrogen beta alumina

Infrared absorption studies of hydrogen beta alumina prepared either from ammonium beta alumina or from silver beta alumina reveal an O-H stretching vibration near 3510 cm -1 . This evidence, showing hydrogen to be chemically bound to the beta alumina framework, is in agreement with previous structural work on DAl 11 O 17 and there is no evidence to support the presence of H 3 O + species. No far-infrared-active mode is observed. In stoichiometric hydrogen beta alumina, HAl 11 O 17 hydrogen is bound only to the spacer oxygen, O(5) giving rise to the 3510 cm -1 line. In non-stoichiometric hydrogen beta alumina, hydrogen is also bound to charge-compensating interstitial oxygens, with a characteristic stretching frequency of 3548 cm -1 . On exposure of anhydrous HAl1 1 O 17 to the atmosphere, water is absorbed and the O(5)-H vibration is perturbed by hydrogen-bond formation with H 2 O. Studies of deuterated crystals and of crystals containing molecules of heavy water support the evidence obtained from work on hydrogenated material.