Relative concentrations of six isomers of Ba@C-74 are evaluated: one cage with isolated pentagons, three isomers with a pentagon-pentagon junction, two structures with one pentagon-pentagon pair and one heptagon. The computations are carried out using the Gibbs energy and point out the endohedral species derived from the sole C-74 cage with the isolated pentagons (D-3h symmetry) as prevailing. The stability computations are in agreement with recent observations. (c) 2006 Elsevier B.V. All rights reserved.