【摘要】 用X射线衍射法测定了乙二胺四乙酸镉(Cd_1.5N₂C₁₀H₁₃O₈·5H₂O)晶体结构。晶体属单斜晶系,空间群为C_2h^?-P2₁/n,晶胞参数:a=9.123A,b=16.468A,c=12.039A,β=91.14°,每个晶胞中含有4个分子。结构测定结果表明:EDTA分子对一个镉离子的螯合较强,形成七配位六啮一水合型的螯合离子。而坐落在对称中心上的另一个镉离子则处于非螯合状态,它与由四个结晶水及两个EDTA分子提供的两个氧原子,构成正八面体配位。经用块矩阵最小二乘修正,最后的一致性因子R=0.050更多还原

【Abstract】 The crystal structure of cadmium salt of EDTA, Cd_1.5N₂C₁₀O₈H₁₃.5H₂O,has een determined by single-crystal, three-dimensional X-ray diffraction study. The orystal elongs to the monoolinic space group C_2h⁵-P2₁/n with cell dimensions: a = 9.123 （3） A, b 6.468 （8） A, c = 12.039 （4） A, β= 91.14 （3）°and there are 4 molecules per unit cell.The result of tructural analysis shows that there are two types of chemical coordination structure of Cd ions resulted rom the different environment found for two kind of Cd ions respectively. One set of the heavy atoms are helated by organic molecules through coordinating atoms （N or O） which are provided by EDTA molecule, he sevcnth coordinating position is occupied by one water molecule, so that the mono-hydrated exadentate helate species are formed in crystal. Another kind of Cd ions which sit on the symmetrical center are onded by four water molecules and two oxygen atoms from EDTA. In Cd_1.5 HY.5H₂O, there are leven protons taking part in hydrogen-bonding, of which one strong intermolecular hydrogen bond （O’₅O’₄ bond length 2.47（1）A） is formed through the nonreplaced proton in Cd（1.5） HY.5H₂O.The inal R index is 0.050 after refined by block-matrix least-square techniques.更多还原