Relative concentrations of nine isomers of Ca@C-82 derived from the C-82 isolated-pentagon-rule satisfying cages are computed in a wide temperature interval. The computations are based on the Gibbs energy constructed from partition functions supplied with molecular parameters from density functional theory calculations. Five structures show significant populations at higher temperatures: C-2v>C-s>C-2>C-3v>C-s. The computed relative stabilities agree well with available observations. (C) 2004 American Institute of Physics.