Theoretical investigation on pentacoordinated silicon compounds of H 3SiX (X=F, Cl, Br, I) with NH 3

Abstract

The halosilane–ammonia adducts H 3SiX·NH 3 (X=F, Cl, Br) were studied with ab initio calculations at the G2(MP2) level. By following the G2(MP2) theory and using effective core potentials for F, Cl, Br, and I atoms, the adducts H 3SiX·NH 3 (X=F, Cl, Br, I) were also calculated. The calculations show that each halosilane can form two kinds of adducts with NH 3. One of them is an axial position adduct and the other is a Si–X bond side-adduct. The former is more stable and easy to be formed. The bonding properties of all adducts were analyzed and the influences of various halogen atoms on structures and stability of adducts were discussed in this paper. It is predicted that adducts of H 3SiX (X=Cl, Br, I) with ammonia or amines will give conducting solutions in solvents, which is well agreed with the experimental results.