Direct observation of nucleus of lithium in a C-60 fullerene cage by neutron diffraction study

The nucleus of the Li+ in a C-60 fullerene by a neutron diffraction study was closer to the inner wall of the fullerene cage than that of the center of its electron density, and the hyperconjugation interaction would arise between the vacant Li+ orbital and the pi orbitals of the hexagonal moiety of the C-60.