Raman spectroscopic evidence for a discrete change in coordination number of rare earth aquo-ions in the middle of the series

Abstract

Raman spectra of glassy aqueous rare earth chloride solutions are reported. A drastic change of frequency in the totally symmetric stretching vibration ( v 1) for the Ln(H 2O) 3+ n ions (Ln 3+ = rare earth ion) is observed between Sm and Gd and is interpreted as evidence for a change in the inner-sphere hydration number of rare earth ions in the series.