# How do orbitals overlap in difluorosilane? [closed]

In $$\ce{SiH2F2}$$ four orbitals of silicon $$(\mathrm{3s},$$ $$\mathrm{3p}_x,$$ $$\mathrm{3p}_y,$$ $$\mathrm{3p}_z)$$ overlap with two hydrogen $$(\mathrm{1s})$$ and two fluorine $$(\mathrm{2p}).$$ I want to know how these orbitals are paired for overlapping. Is it based on strength of overlapping?

A simple model for bonding in this molecule is taking $$\ce {Si}$$ to adopt $$\ce {sp^3}$$ hybridisation, as suggested from the tetrahedral geometry of the molecule. Subsequently, we can refine our model by applying Bent's rule (see more about it here), which tells us that $$\ce {p}$$ orbital character concentrates towards more electronegative substituents. Since the electronegativity of the elements has the following order: $$\ce {F}$$ > $$\ce {H}$$ > $$\ce {Si}$$ with Pauling electronegativity values of $$\ce {3.98}$$, $$\ce {2.20}$$ and $$\ce {1.90}$$ respectively, the $$\ce {3p}$$ character of $$\ce {Si}$$ would concentrate towards $$\ce {F}$$ while $$\ce {3s}$$ character concentrates towards $$\ce {H}$$. Thus, we would have $$\ce {Si}$$ using $$\ce {sp^{3+x}}$$ orbitals to form the bonds with $$\ce {F}$$ and $$\ce {sp^{3-x}}$$ to form the bonds with $$\ce {H}$$, where $$x$$ is some small value between $$\ce {0}$$ and $$\ce {1}$$.