This work examines, by using quantum-chemical calculations, the electronic and optical properties of three highly symmetrical isomers of the C60Cl24 halogenofullerene. The ground state properties of these derivatives are calculated using the semi-empirical Hartree-Fock AM1 approach and discussed in terms of symmetry, charge distribution and electronic conjugation on the fullerene cage. Starting from the optimized geometry, the optical absorption spectrum of each molecule is calculated at the semi-empirical Hartree-Fock INDO/S level, using a large configuration interaction scheme. The results are compared to a visible and near-infrared absorption spectrum of C60Cl24, recorded in solid matrices, at low temperature. From the comparison, it is concluded that a D-2h C60Cl24 isomer is responsible for the spectrum observed. The spectrum is analyzed in terms of electronic singlet transitions. (C) 2003 American Institute of Physics.