Relative concentrations of four selected isomers of La@C-82 are computed from the Gibbs energy derived from partition functions supplied with parameters from density functional theory calculations. An agreement with experiment can be reached for temperatures roughly from 1000 to 1300 K when the C(2)v species is the major isomer followed by an isomer that undergoes C(3)v/C-s symmetry reduction while the intrinsically C-s species comes as a still less populated third product. It is suggested that the C-3v isomer can be suppressed in the condensed phase by its higher reactivity. (C) 2004 Elsevier B.V. All rights reserved.