Abstract: The complex (这里有图片19930805-1051-1.gif) was prepared in organic solvent.The crystal belongs to space group P1 of triclinic system.The cell parameters are a=0.8986(2) nm, b=0.9750(2) nm, c=2.3687(4) nm, α=82.70(1), β=81.29(2).γ=61.67(1)°, V=1.8020(6) nm³, Z=2, D_c=1.56 g/cm³, R=0.036.The result shows that the central uranyl ion is coordinated by six oxygen atoms, two of them are from the carbonyl groups of two octyl-caprolactam molecules, and the other four are from two nitrate groups.In the crystal cell, a dimer was formed, owing to the attraction of four long carbon chains in the two complex molecules.

Key words: Octylcaprolactam, Uranyl, Crystal strucure