The single crystal of Ce(NO3)3.L (L = dibenzo-18-crown-6) was prepared and characterized by elemental analyses, IR spectra, molar conductance, DTA and thermogravimetry. The structure of this complex was determine by x-ray single crystal diffraction anal. The crystal of the complex is tetragonal, space group P41212 with a 8.649(3), c 33.388(21)? Z = 4, dc = 1.83, d0 = 1.82 g/cm3. The cerium ion lies more or less at the center of the ring consisting of 6 O atoms of the crown. The 3 nitrate groups in the complex are bidentate and 2 of them are coordinated on the less hindered side while the other is bonded on the opposite side. The coordination no. of Ce(III) ion is 12. The average bond lengths are 2.648?for the 6 Ce-O(crown) bonds and 2.664?for the 6 Ce-O(NO3-) bonds.

Key words: INFRARED SPECTROPHOTOMETRY, CRYSTAL STRUCTURE, MOLECULAR STRUCTURE, X-RAY DIFFRACTION ANALYSIS, CROWN ETHER COMPOUNDS, CHEMICAL PROPERTY, BENZENE P, NITRATE, CERIUM COMPOUNDS, CHARACTERIZATION