Coordination Number Change of Ln3+ Ions in Anhydruos Alcoholic LnCl3 Solutions in the Glassy State

摘要

Raman spectroscopic measurements were carried out for anhydrous alcoholic rare earth chloride solutions (LnCl3 · 20ROH; ROH = MeOH, EtOH, and n-PrOH) in the glassy state at liquid nitrogen temperature. Series behavior of the Ln–Cl stretching Raman band is examined in conjunction with the formation of chloro complexes. The results are summarized as follows: (1) Comparing the results with those in the liquid state at room temperature, more Cl- ions tend to coordinate to heavy rare earth ions in the three alcohol solutions upon going from a liquid to a glassy state, while the coordination number of the Cl- ions of the light rare earth ions remains almost unchanged on vitrification. (2) In the former half region of the rare earth series, the coordination number of the Cl- ions of the rare earth ions in the methanol LnCl3 solution is apparently the same as that in the ethanol LnCl3 solution. (3) In the latter half region, the higher chloro complexes, such as [LnClx+1(ROH)y-2](z-1) (x + y = 8; x = 1, z = 2 or x = 2, z = 1) are more abundant in the methanol LnCl3 solution than in the ethanol and n-propanol LnCl3 solutions.