Hyperfine structure of Sc@C82 from ESR and DFT
  The electron spin g- and hyperfine tensors of the endohedral metallofullerene Sc@C82 are anisotropic. Using electron spin resonance (ESR) and density functional theory (DFT), we can relate their principal axes to the coordinate frame of the molecule, finding that the g-tensor is not axially symmetric. The Sc bond with the cage is partly covalent and partly ionic. Most of the electron spin density is distributed around the carbon cage, but 5% is associated with the scandium d_yz orbital, and this drives the observed anisotropy. 
G. W. Morley, B. J. Herbert, S. M. Lee, K. Porfyrakis, T. J. S.   Dennis, D. Nguyen-Manh, R. Scipioni, J. van Tol, A. P. Hor...