On the basis of the complete energy matrices for a d(7) configuration ion in D-2d symmetry ligand-field, the local structure parameter theta = 52.60 degrees for [CoCl4](2-) clusters in Cs3CoCl5 crystal is determined. It is shown that the ligand-field calculation results of theta are associated with the equivalent positions of the effective charges of chlorine ions, which are slightly different from the nuclear positions of chlorine ions theta(0) = 53.0 degrees +/- 0.2 degrees found by X-ray diffraction experiment. This difference means that there exists an obvious polarization effect for the electron clouds of chlorine ions in Cs3CoCl5 crystal. Furthermore, the theoretical g-factors and paramagnetic susceptibility are in agreement with the experimental findings. (C) 2011 Elsevier B.V. All rights reserved.