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本文报道了用x-射线衍射法测定的硝酸镧和硝酸钕的15-王冠醚-5络合物[La(NO_3)_3·C_(10)H_(20)O_5(La—L)和Nd(NO_3)_3·G_(10)H_(20)O_5(Nd—L)]的晶体结构.测定表明,La—L和Nd—L是同构的.稀土金属离子没有进入冠醚环的平均平面,而是被夹在冠醚环与三个硝酸根的中间.冠醚环上的五个氧从一侧全部同中心金属离子形成配位键,而三个硝酸根则各有两个氧原子从另一侧与金属离子络合,使络合分子的稳定性得到满意的解释.而La—O平均键长比Nd—O的平均键长大0.056,同镧系收缩理论相符.
In this paper, we reported the synthesis of 15-crown-5 complexes [La (NO 3) 3 · C 10 H 20 O 5-La and L-Nd 3+ NO_3) _3 · G_ (10) H_ (20) O_5 (Nd-L)] .The results show that La-L and Nd-L are isomorphic.The rare earth metal ions do not enter the average plane of the crown ether ring, But is sandwiched between the crown ether ring and the center of the three nitrates.The five oxygen on the crown ether ring forms a coordination bond with the central metal ion from one side and the three nitrates each have two oxygen atoms from The other side of the metal ions complexed, so that the stability of the complex molecules were satisfactorily explained.The La-O average bond length Nd-O average bond length 0.056 , consistent with the theory of lanthanide contraction.