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堆积模型及其应用 Ⅰ.三氯化镧尿素配合物[LaCl2(urea)6]·Cl分子结构的推测与测定
Cone Packing Model and its Applications I. Molecular Structure of Dichlorohexaurealanthanium Chloride [LaCl2(urea)6]·Cl Prediction and Structural Characterization
【摘要】 <正> 镧系元素具有形成高配位数的特点,但由简单配位形成的多面体,最高配位数只能达到九,例如,[Ln(H2O)9]+[2]。有些从化学式来看符合九配位的化合物,如LnCl3(H2O)6实际结构是八配位[LnCl2(H2O)6]+[3]或六配位[LnCl3(H2O)3]·3H2O[4])。这种情况促使我们对另一系列化合物LnCl3(urea)6[5]产生兴趣。我们根据堆积模型推测LaCl3(urea)6的实际结构应当是[LaCl2(urea)6]+Cl-(见图1、2)。培养了这一化合物的单晶,进行了结构测定。本文报道有关结果。
【Abstract】 The actual molecular structure of urea complex of lanthanium trichloride, LaCl3(urea)6, with its SAS value 0.94, is expected to be [LaCl2(urea)6] Cl according to therecently developed cone packing model. This prediction is experimently confirmed byX-ray crystallography. Crystal data: [LaCl2 (urea)6] Cl, orthorhombic, Dm=1.79gom-3 Dc=1.83gom-3, a=15.25, b=9.22, c=16.11A, space group Pna21, z=4. The struc ture is a distortedsquare antiprism with two chlorides and six ureas coordinated to the lanthanium. Thebond angles are in fairly good agreement with the calculated results.
- 【文献出处】 化学学报 ,Acta Chimica Sinica , 编辑部邮箱 ,1989年03期
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