MgCl_2·6H_2O·2CH_3CON(CH_3) _2的制备与表征

The Preperation,Characterization and Structure of Coordination Compound MgCl_2·6H_2O·2CH_3CON(CH_3) _2

配合物 MgCl_2·6H_2O·2CH_3CON(CH_3) _2(CH_3CON(CH_3) _2简称 DMA)经化学分析和 x-射线结构分析,确定其化学式为[Mg(H_2O)_4(DMA)_2] Cl_2·2H_2O,晶体属单斜晶系,空间群 C_2,晶胞参数:a=1. 6391nm,b=0. 8012nm,c=0. 7374nm,β=91. 28,z=2. 晶体结构是用 Patterson 法和 Fourier 合成法解析的,经全矩阵最小二乘法修正。最后 R 因子降至0. 090. 结果表明,配合物晶体中 Mg^(2+)与四个 H_2O 分子和两个 DMA 分子以八面体方式相连,形成配阳离子[Mg(H_2O)_4(DMA)_2] ^(2+),两个 Cl^-离子和其余的两个 H_2O 分子分别充填于这些配离子之间.本文还对该配合物进行了 IR、TG-DTG 等研究.

The title coordination compound was obtained from the system MgC_2- H_2O-CH_3CON(CH_3) _2(Dimcthylacetamide,DMA)and characterized by chemical analysis,IR,TG-DTG,density and optical properties.Its crystal structure was deter mined by x-ray diffraction method.The results reveal that the crystal is of monoclinic system and its space group is C_2 with a=1. 6391nm,b=0. 8012nm,c=0. 7374nm,β=91. 28°,V=0. 9668nm^3,Z=2Dm=1. 281g/cm^3,D_c=1. 295/cm^3,refractivein dexes:Ng=1. 516,Nm=1. 495,Np=1. 481,2V=39°(cal.Volue 41°).The structure of the crystal was solved by Patterson method and Fourier synthsis,then relined by the full-matrix least square method.The final R factor is 0. 090. The results show that the crystal consists of coordinate ion(Mg(H_2O)_4(DMA)_2) ~2(+),two H_2O molecules and two Cl^-ions.In the coordinante ion foue H_2O and two DMA are coordinated to Mg^(2+)ion octahedrally.The two Cl^-ions and the other H_2O molecules are filled in the gaps of coordinate ions and may be linked to the coordinated H_2O molecules through H-bonds.