The tri(n-butyl)tin 3-amino-2-pyrazine formic ester polymer [n-Bu 3Sn (O2CC4H2N2NH 2-o)]n has been synthesized and characterized by IR, 1H NMR spectra and elemental analysis. Its crystal structure has been determined by X-ray diffraction. The crystal belongs to monoclinic space group P21/c with a= 1.0577(2) nm, b= 1.0836(2) nm, c=1.9052(4) nm, β=100.604(3)°, Z=4, V=2.1463(8) nm3, Dc=1.325 Mg·m-3, μ(Mo Kα)=1.202 mm-1, F(000)=880, R1=0.0393, wR2=0.1133. In the complex, tin atoms are five-coordinated distorted trigonal bipyramid configuration...