Synthesis and characterization of the europium fullerides EuxC60 (x=1-6)

Europium fullerides EuxC60 (x = 1-6) were prepared by metal ammonia solution synthesis. The products were investigated by X-ray powder diffraction, optical spectroscopy, FTIR, mass spectrometry, and magnetic susceptibility. All products were amorphous by powder X-ray diffraction and were free of ammonia as determined by mass spectrometry. Products prepared with x = 1, 2, 3 showed the presence of unreacted C-60 in the optical spectra, FTIR spectra, and the powder diffraction pattern. FTIR spectra of the EuxC60 prepared with x 3 show red-shifted frequencies of F-1u(4) at 1399 and 1352 (1411) cm(-1), suggesting the presence of C-60(-) and C-60(6-). FTIR spectra of EuxC60 samples prepared with x = 4, 5, 6 also show red-shifted frequencies and are discussed in detail. Magnetic susceptibility measurements show Curie-Weiss behavior above 50 K with experimental magnetic moments of 6.6 (1), 6.9 (1),and 5.9 (1) mu(B)/Eu for x = 3, 4, 5 samples, respectively.