In order to study the relative stability of the carboxylate cluster systems
of the ‘wheels’ type [CrnFn((CH3)3COO)2n] (n=4,6,8,10,12) the investigations of
the geometrical and electronic structure  and total energy Etot per one Cr atom
(n) of these compounds were carried out. The complexes were considered in their ferromagnetic state. Their geometry was studied by the MM2/MM3 method (from
the HyperChem’s computational package) and the results obtained were found close to the
experimental data*. The electronic structure of the complexes was calculated, using the basis
set STO-3G from GAUSSIAN 2003 packages by means of the methods Hartree-Fock and DFT
(B3LYP functional). Calculated data are given partly in the Figs. 1,2.

The results obtained allow one to draw the following conclusion: both of the applied quantumchemical methods show that the compound with n=8 (see above) is the most stable one in the series under investigation. This conclusion is experimentally confirmed*.
Acknowledgment. This work was supported by INTAS(No.03-51-4532).
*Gerbeleu N. V., Struchkov Yu. T., Timco G. A. Dokl. Akad. Nauk SSSR 1990,
313, 1459.