Comparison of the spectra of LiMn2O4 synthesized at 50 °C obtained with 6Li (a) and 7Li (b) MAS NMR at a MAS spinning speed of ∼9 kHz and a magnetic field strength of 4.7 T (200 MHz for 1H). Reproduced from ref. 22 with permission from American Chemical Society, Copyright 1998.