One cadmium（Ⅱ）coordination polymer [Cd（phen）（4,6-dimethyl-5-nitro-isophtha-lic acid）]n（1）has been synthesized with 4,6-dimethyl-5-nitro-isophthalic acid,phen（phen = 10-phenanthroline）,and cadmium nitrate in the mixture of DMSO：H2O（V：V = 2：1）.Crystallogra-phic data for this complex：monoclinic,space group P21/c,with a = 11.668（2）,b = 11.841（6）,c = 14.446（2）,β = 102.440（4）°,V = 1.9491（8）3,Dc = 1.805 g/cm3,Z = 1,F（000）= 1056,GOOF = 0.999,R = 0.0280 and wR = 0.0662.The crystal structure analysis indicates that the cadmium ion is coordinated with two nitrogen atoms of one 1,10-phenanthroline molecule and five oxygen atoms from three 4,6-dimethyl-5-nitro-isophthalic acid molecules.The curve of TGA shows that 1 is stable up to 380.0 ℃.
