We present total energy calculations based on the relativistic density-func
tional theory which provide electronic and geometric structures of a La@C-8
2 molecule and those of a La@C-82 crystal. We find the hybridization of La
and C states which cause significant modulation of the electronic structure
of the C-82 molecule. The La@C-82 crystal is found to be metal with half-f
illed energy band at the Fermi level.