Abstract: Bonding trends in SiX₄^m system are studied using the methods of ab initio molecular orbital at HF/STO-3G, HP/3-21Gand HF/6-31Glevels.The calculated results indicate that all species considered except SiLi₄ have local minima.Comparing with experimentally known molecules SiH₄, SiF₄ and SiCl₄, the species SiHe₄⁴⁺, SiNe₄⁴⁺, and SiAr₄⁴⁺ containing rare gas, isoelectronic structure with previous molecules, respectively, have larger probability of bonding trends than species containing alkali metals Li and Na, alkali-earth metal Be and Mg.It could be expected that SiHe₄⁴⁺, SiNe₄⁴⁺ and SiAr₄⁴⁺ could be candidates of probably stable new molecules.

Key words: Small silicon compounds, Ab initio molecular orbitals, Molecular bonding trends