A binuclear copper(Ⅱ) compound, {Cu2(tacn)2[μ-(MeN)2C2O2]}[(MeNH) 2C2O2](ClO4)2 (tacn=1, 4, 7-triazacyclononane) has been synthesize dand characterized by IR, elemental analysis, ESR, electronic spctrum and X-ray diffraction. Crystal data: monoclinic, space group P21/n, a=0.72572(16) nm, b=2.5616(6) nm, c=0.9128(2) nm, β=90.096(5) °，V=1.6969(7) nm^3, Dcald=1.590 Mg.m^-^3, Z=2, F(000)=840, R1=0.0529, wR2=0.1341, Gof=1.028, △ρ=632～390 e.nm^-^3. The complex is packed by one centrosymmetry binuclear copper unit, neutral oxalamide molecule and ClO^-~4 anion. In the molecule of the complex, two Cu(Ⅱ) ions are all five coordinte with distorted squarepyramid configuration. The magnetic susceptibilities (5～300 K) indicated that the binuclear (Ⅱ) cores wer antiferromanetic coupling (J=-219 cm^-^1, g=1.98).

Key words: CRYSTAL STRUCTURE, CYCLONONANE P, DINUCLEAR COMPLEX, COPPER COMPLEX, MACROCYCLIC COMPOUNDS, ANTIFERROMAGNETISM, NITROGEN HETEROCYCLICS