ON NATURE OF VISIBILE ABSORPTION BANDS IN METAL-AMINE SOLUTIONS

The effects of temperature on the sodium 660-nm absorption band are investigated in several EtNH2-NH3 solvent mixtures. The spectrum of the I- ion is recorded at 19° in the same mixtures. The data indicate that the 660-nm metal band exhibits solvent and temperature dependence features characteristic of a ctts (charge transfer to the solvent) spectrum of a negative ion. The Stein and Treinin relation for ctts transitions is also found to be obeyed by the spectra of sodium, potassium, rubidium, and cesium in ethylamine. It is suggested that the visible bands observed in metal-amine (and ether) solutions around 660, 850, 920, and 1030 nm should be correspondingly attributed to the Na-, K-, Rb-, and Cs- metal ions.