Abstract: The synthesis, the crystal and molecular structure of neodymium complex NdA₂NO₃(C₂H₅OH)₂(A= 2-ethyl hexanoate group) are presented in this report. The crystal and molecular structures were determined by single crystal X-ray diffraction techniques with a four circle diffrac-tometer to give a final Rvalue of 0. 0997. The crystal is triclinic with a space group P1. The unit cell parameters are:a = 9. 448(4)Å, b= 12. 146(4)Å, c= 12. 974(5)Å, a=71. 56(3)°, β = 98.45(3)°, γ=98.62(3)°, V=1388.6(9) ų, Z = 2, d_calc=1. 397 g/cm³. Each two neodymium atoms in crystal are connected with two bridging carboxyl groups to form a chain polymeric molecule. The middle point of the linking line of two neodymium atoms is on the axis a. In addition, every neodymium is coordinated by 4 oxygen atoms. Two of them are from a bidentate nitrate, and the others from two ethyl alcohol molecules. The coordination number of neodymium is 8 and the coordination polyhedron of neodymium takes an arrangement of a distorted delta dodecahedron.

Key words: Neodymium, 2-ethyl hexanoate, Complex, Triclinic crystal system, Space group P1