Lithium multiple resonance

Both the V and Li NMR spectra show multiple vanadium and lithium local environments for the as-synthesized material x = 0.15), and the spectra cannot be explained by using a simple model based on the number of crystallographically distinct vanadium sites. On Li-ion intercalation, the V resonances sharpen and shift to higher frequencies (Figure 15) three sharp resonances along with two broader resonances are clearly resolved for the samples prepared at potentials of 3.4 and 3.0 V (x = 0.3 and 0.5, respectively). This behavior is consistent with solid—solution behavior in this potential range and is ascribed to the presence of localized defects at X close to 0 and electron delocalization for 1 > x > 0.05. Three lithium sites were observed in the Li... 

Using low-temperature 13C NMR spectra, Reich and coworkers found that phenyl-lithium-6Li (18) in diethyl ether-<7 0 consists of an equilibrium between dimers and tetramers25. The spectra of these species were well resolved and identified by their one bond 13C—6Li coupling constants and multiplicities of their 13C resonances for lithium bound carbon, 7.6 Hz and 1 2 3 2 1 for dimers and 5.1 Hz and 1 3 6 7 6 3 1 for tetramers. On increasing the temperature above 170 K, the coupling constants and shifts between the species progressively average out. Line shape analysis provides the... 

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