Raman spectra of thallium(I) nitrate solutions in liquid ammonia

Abstract

Raman spectra are reported for TlNO₃ solutions in liquid ammonia, ranging in composition from TlNO₃/3NH₃ to TlNO₃/26.7NH₃ mole ratios. All the spectra were obtained from solutions at ambient temperatures. Intensity changes in the N—H stretching region are correlated with the effects of the electrolyte on the solvent structure. An intense broad band at ∼ 1110 cm^–1 has been assigned to the symmetric deformation mode of NH₃ engaged in strong σ-interactions with Tl⁺ ions. The D_3h selection rules for the unperturbed NO^–₃ anion break down in concentrated solutions of TlNO₃ in NH₃ and spectral evidence is presented to support a new π-interaction model for Tl⁺–NO^–₃ ion-pairs.