硝酸镧与冠醚(2,2)配合物的晶体及电子结构研究  

STUDY ON CRYSTAL AND ELECTRONIC STRUCTURE OF THE COMPLEX OF LANTHANUM NITRATE WITH DIAZA-SUBSTITUTED 18-CROWN-6

作　　者：梁福沛[1] 李振祥[1] 金钟声[1] 倪嘉缵[1] 高志昌[2] 姚钟麒[2] 

机构地区：[1]中国科学院长春应用化学研究所,长春130022 [2]中国科学院兰州化学物理研究所,兰州730000

出　　处：《无机化学学报》1991年第1期18-22,共5页Chinese Journal of Inorganic Chemistry

基　　金：国家基金资助课题

摘　　要：用X-射线单晶衍射法测定了硝酸镧与冠醚(2,2)配合物的晶体结构,发现其具有与报道的Eu(NO_3)_3(2,2)配合物不同的配位方式.晶体属于三斜晶系,空间群P(?),晶胞参数为a=10.312(2)(?);b=12.745(3)(?);c=8.917(2)(?);α=103.79(2)°;β=112.73(2)°;γ=83.68(2)°;V=1049.5(5)(?)~3;F(000)=587.88;Z=2.结构用重原子法解出;R值为0.0292.用INDO法计算了配合物的净电荷分布,电子结构、键级.结果表明,镧与配位原子间的键具有一定程度的共价性.镧的5d轨道对共价性的贡献最大,而4f轨道基本上不参与成键.La-N比La-O(醚)间存在较强的作用,增大了配合物的稳定性.The crystal structure of the complex of lanthanum nitrate with diaza-substituted 18-crown-6 (2,2)has been determined from four circle diffractometer data. The results indicate that the structure of complex differs from that of Eu(NO3)3 (2,2) compound. The crystal belongs to triclinic system with space group P1. Crystallographic data are as follows: a= 10.312(2) A; b 12.745(3)A; c=8.917(2)A; α= 103.79(2) °; β= 112.73(2) °;γ = 83.68(2) °; V= 1049.5(5) A; F(0 0 0) = 587.88; Z=2. The crystal structure was solved by heavy atom method, R = 0.029. The charge distributions, electronic structure and the bond orders have been studied by INDO calculation. The results of calculation show that the bonds between lanthanum and coordination atoms have certain extent covalency. The main contribution to bonding covalency is due to the 5d orbitals of La while the 4f orbitals almost do not participate in covlent bonding. Interaction between La and N is stronger than that between La and O, which increases the stability of the coordination compound.

关 键 词：硝酸镧 冠醚 配合物 晶体结构 

分 类 号：O614.331[理学—无机化学]