La(NCS)_3·4.5H_2O与18C6在乙醇中的配合行为及热化学研究  

Study on Coordination Behavior between La(NCS)3·4.5H_2O and Crown Ether 18C6 in Absolute Ethanol and Thermochemistry

作　　者：薛岗林[1] 党高潮[1] 杨一心[1] 王小芳[1] 张泉珍 任德厚[1] 

机构地区：[1]西北大学化学系,西安710069

出　　处：《无机化学学报》2001年第4期501-506,共6页Chinese Journal of Inorganic Chemistry

摘　　要：采用半微量相平衡方法研究了三元体系La(NCS)3·4.5H2O-18C6-C2H5OH在298.15K的溶解度,测定了各饱和溶液的折光率。该体系形成两种化学计量的配合物,其组成分别为:犤La(NCS)318C6犦·4.5H2O?和犤La2(NCS)6(18C6)3犦·9H2O?,?为溶解一致化合物,?为溶解不一致化合物。依据相平衡结果,制备了两种固态配合物,用IR,DTG,TG,DSC及电导对配合物进行了表征。测量了298.15K时18C6,配合物?在无水乙醇中的热效应,依据本文所设计的热化学循环,求得了溶解一致化合物?的标准生成焓,ΔfHm(犤La(NCS)318C6犦·4.5H2O,s)为-3196.7kJ·mol-1。The solubilities of the ternary system, La(NCS)3·4.5H2O 18C6 C2H5OH, have been investigated by a semimicro method at 298.15K for study of phase equilibrium and the refractive indexes of saturated solutions have been determined. The results indicate that there are two kinds of coordination compounds formed in the system, their chemical compositions are: [La(NCS)3(18C6)]·4.5H2O? and [La2(NCS)6(18C6)3]·9H2O?,? is congruently soluble, and ? is incongruently soluble. The coordination compounds ? and ? have been prepared on the basis of the phase equilibrium and characterized by IR,DTG,TG,DSC and conductivity measurements. The integral heats of solution of 18C6 and the coordination compound ? in C2H5OH have been measured calorimetrically at 298.15K. By means of a thermochemical cycle suggested in this paper, the standard molar enthalpy of formation for ? was obtained and the value ([La(NCS)3(18C6)]·4.5H2O, s) = -3196.7kJ·mol-1 was recommended.

关 键 词：半微量相平衡 热化学 配合物 冠醚18C6 异硫氰酸镧 标准生成焓 

分 类 号：O614.331[理学—无机化学] O642[理学—化学]