Etude, par Spectroscopie de Vibration Infrarouge et Raman, du Dihydrate de l'Acide Perchlorique dans les Etats Désordonnés: Verre et Liquide

The infrared and Raman spectra of the mixture HClO4 · 2H2O in the glassy and liquid states have been investigated. Two species have been characterized: (a) the dioxonium perehlorate where the H5O2+ and ClO4− ions are linked by hydrogen bonds weaker than in the crystal (νOH(H5O2+) = 3430 and 3460 cm−1 respectively in the glass and liquid state Raman spectra and 3340 cm−1 for the crystal). (b) an ionic association, O3ClO−…H(OH)HOH2+, in which the vibrational motions of the terminal H2O molecules are characterized by δOH = 1530 and 1550 cm−1 and νOH = 3480 and 3520 cm−1 respectively in the glass and liquid state Raman spectra and in which ν1(ClO4−) shifts to lower frequencies (Δν = −12cm−1).