Raman spectroscopic and DTA studies of aqueous rare earth thiocyanate solutions

Raman measurements were carried out for aqueous rare earth thiocyanate [Ln(SCN)(3); Ln=La(3+)similar to Lu3+] solutions (R=20; R is moles of water per moles of salt) in the liquid state at room temperature and in the glassy state at liquid-nitrogen temperature. Raman band shifts for the C-S and C-N stretching bands of the SCN- ion indicated that the SCN- ion binds to a rare earth ion only at the N end. Thus, these solutions are better called as aqueous rare earth isothiocyanate solutions. Glass transition temperatures (T-g's) of these solutions were also measured. The T-g values have a distinct extended s-shape and are compared with the previous ones for aqueous rare earth chloride and perchlorate solutions. Series behavior of the T-g results is discussed in conjunction with the coordination number change in the middle of the series.