Electron diffraction study and CNDO/2 calculations on the complex of aluminium trichloride with ammonia, Cl 3Al.NH 3

Abstract

The molecular geometry of the complex of aluminium trichloride with ammonia, Cl 3Al.NH 3, has been studied by electron diffraction. The most important internuclear distances in terms of r a parameters are as follows: r(Al-Cl) = 2.100±0.005 Å, r(Al-N) = 1.996±0.019 Å, r(Cl·Cl) = 3.569±0.011 Å and r(Cl·N) = 3.165±0.012 Å. The Cl-Al-Cl bond angle in terms of an approximate r a structure is 116.9°. The assumptions of a staggered model in the structure analysis was justified by CNDO/2 calculations. The experimental data indicate strong linkage between the donor and acceptor parts. The flat pyramidal average configuration of the AlCl 3 part of the complex suggests planar equilibrium structure for free AlCl 3. Variations in the bond configurations of the donor and acceptor parts, as compared with those of the respective free molecules, are discussed.