All attempts to prepare light lanthanide dicyclopeutadienyt chloride failed,due to the disproportionation reaction. The crystal complex of [(η~5-C_5H_5)_2NdCl.OC_4H_8]_2 was successfully prepared by the reaction of NdCl_3·2C_4H_8O with cyclopentadienyl sodium (molar ratio 1:1.8)in tetrahydrofuran at room temperatureThe composition of the title compound was determined by the methods of elemental analysis, infrared spectroscopy and photoelectron spectroscopy. The crystal structure of [(η~5-C_5H_5)_2NdCl·OC_4H_8]_2 was determined from single crystal X-ray diffraction. Data were collected at-60℃ under dry nitrogen atmosphere.The complex crystallizes in the monoclinic space group P2_1/c,with Z=2. Lattice parameters are: a=8.201(3), b=21.589(6),c=8.596(3),β=109.10(3)°.The structure was solved by Patterson and Fourier techniques and refined by least-squares to a final conventional R=0.0636 for 1680 reflections. There are two Nd atoms in the dimeric unit which are bridged asymmetrically by the two chlori All attempts to prepare light lanthanide dicyclopentadienyt chloride failed due to the disproportionation reaction. The crystal complex of [(η ~ 5-C_5H_5) _2NdCl.OC_4H_8] _2 was successfully prepared by the reaction of NdCl_3 · 2C_4H_8O with cyclopentadienyl sodium (molar ratio 1 : 1.8) in tetrahydrofuran at room temperatureThe composition of the title compound was determined by the methods of elemental analysis, infrared spectroscopy and photoelectron spectroscopy. The crystal structure of [(η ~ 5-C_5H_5) _2NdCl · OC_4H_8] _2 was determined from single crystal The complex crystallizes in the monoclinic space group P2_1 / c, with Z = 2. Lattice parameters are: a = 8.201 (3), b = 21.589 (6 ), c = 8.596 (3), β = 109.10 (3) °. The structure was solved by Patterson and Fourier techniques and refined by least-squares to a final conventional R = 0.0636 for 1680 reflections. There are two Nd atoms in the dimeric unit which are bridged asymmetricall y by the two chlori