The splitting of the ERP spectrum of a single Gd3+ ion into four intense components has been observed in crystals of Pb-5(Ge1-xSix)(3)O-11 solid solutions, which is caused by the appearance of silicon ions in three nearest germanium spheres. The atomic structure of the observed centers has been determined. The conclusion has been made that silicon mainly substitutes for germanium in oxygen tetrahedra and for one of germanuim atoms in oxygen bitetrahedra, which is based on comparison of the measured ratio of component intensities with the results of the calculation of the concentrations of Gd3+ associations with silicon ions.