The reaction of C5H4RLi with FeCl2 gave nine new compounds of Fe(C5H4R)2 [R = C (CH3)2C5H4CH3-p(-m,-o), C5H10C6H5, C(Me)2C6C4OCH3-o, C6H10C6H4CH3-p (,-m,-0), C6H10C6H4OCH3-p]. The compositions of compounds were determined through elementary analysis. The structural determination was made by IR and H'NMR. Mossbauer spectra were taken at room temperature. The IS and QS values are 0.41-0.45mm/s and 2.3-2.5mm/s., respectively. The solid state structure of the complex has been determined by a single crystal x-ray diffraction study, crystal data for Fe[C5H4C(CH3)2C6H5]2: a = 17.988(2)A, b = 17.411(2)A, c = 7.496(1)A, alpha = beta = 90-degrees, r = 112.23-degrees, Z = 4, monoclinic form, space group C2/c. Our conclusions are: in pi-acceptor ligand, the nucleophilic substituents decrease and the electrophilic substituts increase the metal to ligand electron cloud shift, which results in a decrease of an increase in the strength of the coordinate bonds and in the stabilization of the complexes by their steric effect.