二—(2,2'—联吡啶)—三—(硝酸)合镧(Ⅲ)La(C_(10)H_8N_2)_2(NO_3)_3的电子结构和化学键

引 言 希土化合物由于涉及f轨道,用分子轨道方法有一定困难,前人曾采用过多种处理方法。文献8]报导了希土-2,2’-联吡啶配位方法和性质研究。文献8],9]对镧与2,2—联吡啶,硝酸配合物的合成,性质和结构亦作过研究。本文采用适用于镧系元素化合物电子结构计算的自旋非限制的INDO方法来研究La(C_(10)H_8N_2)_2(NO_3)_3的电子结构和化学键。

ELECTRONIC STRUCTURE AND CHEMICAL BONDS OF BIS(BIPYRIDYL)-TRI(NITRATE)-LANTHANUM (III) La(C_(10)H_8N_2)_2(NO_3)

The bis(bipyridyl)-tri(nitrate) lanthanum(III) La(C10H8N2)2(NO3)3] has been studied by INDO semi-empirical molecular orbital method in the paper. The composition and bonding character of each occupied molecular orbital has been discussed. The coordination of two bipyridine to lanthanum reduces the positive charge on the lanthanum ion, increasing the covalence of the bonds. So that the lanthanum complex is more stable. The covalcnt composition is about 52% in La-O bonds. The coordination ability of bipyridine is a little stronger than that of nitrates in the complex. The electronic configuration of La is (6s)0.363 (6p)0.596 (5d)1.721 (4/)0.003. The bonding between lanthanum and oxygen or nitrogen is mainly due to the participation of La(Sd) orbitals, and to a less extent, due to that of La(6p) and La(6s) orbitals. The La(4f) orbitals do not participate in the covalent bonding at all.