Spectroscopic investigation of a series of sodium lanthanide decatungstates, Na(7)H(2)Ln(III)(W5O18)(2)center dot nH(2)O (Ln: La-Yb): The contribution of 4f(n) electrons to bonding interaction among Ln(III) and polyoxotungstates

A series of sodium lanthanide decatungstates, Na(7)H(2)Ln(III)(W5O18)(2) . nH(2)O (Ln = La-Yb) was synthesized and characterized by spectroscopic analyses. The W-183-NMR chemical shifts for the W adjacent to Ln(III) correlated well. with the contact parameter in the lanthanide induced shifts, (Sz), which had been theorized by Golding. The FT-Raman stretching frequencies for the Ln-O-W bonding also correlated with the theoretical magnetic moments induced from the 4f(n) electrons in the lanthanide ions in addition to the ionic radii of Ln(III). A direct contribution of the 4f(n) electrons to the bonding interaction among Ln(III) and the oxotungstates is suggested.