Spettri Raman e nell'ultrarosso prossimo di soluzioni acquose a diversa concentrazione di acidi e basi forti inorganici.

Bertoluzza, Alessandro ; Morelli Bertoluzza, Maria Antonietta ; Fagnano, Concezio

Atti della Accademia nazionale dei Lincei. Rendiconti della Classe di scienze fisiche, matematiche e naturali, Série 8, Tome 56 (1974) no. 5, pp. 787-797

Résumé

Raman (1450-4500 cm-1) and near i.r. spectra (4000-7500 cm-1) of HCl and NaOH aqueous solutions are discussed. Concentrated solutions contain H+(H2O)n and OH-(H2O)n ions; they are characterized by a first "coordination-sphere" with strong (O--H--O)+ and (O--H--O)- hydrogen-bond between H+, or OH-, ions and water molecules and by successive "coordination-sphere" with OHO hydrogen bonds of decreasing strength. Concentrated solutions display a large Raman continuous band that extends from the region of stretching vibrations to that of HOH bending vibrations, and a continuous absorption in the near i.r.; they can be attributed to a double minimum potential function with a low barrier either in (0--H--0)+ or in (O--H--O)- and to interaction forces (induced dipole, protonic dispersion, ecc.) operated by these bonds. For aqueous concentrated solutions of corresponding salt, NaCl, strong O--H--O hydrogen-bonds are not observed. Finally, for basic solutions, strong (O--H--O)- hydrogen-bonds are formed for the interaction of non-bonding electronic couple of OH- ion with the hydrogen of a contiguous water molecule.