# Can one describe the bonding of Na to F in terms of molecular orbital theory? What about valence bond theory?

I would kindly appreciate an explanation in terms of the two accepted quantum mechanical theories -valence bond & molecular orbitals- for the electronic energy level structure in natrium fluoride $$\ce{NaF}$$.

I read here that from a non-quantum perspective the $$\text{3s}$$ electron of $$\ce{Na}$$ "jumps" to join the $$7$$ electrons of the $$\text{2p}$$ level of $$\ce{F}$$. This way, the $$\text{Na}$$ atom becomes the $$\ce{Na+}$$ ion, while the $$\ce{F}$$ atom becomes the $$\ce{F-}$$ ion. All nice until now but handwaving, or high-school level if you prefer.

So how is then the $$\ce{Na-F}$$ bond (thus the molecule) defined in terms of the electronic wavefunctions of the two original atoms?

How is this generalized to $$\ce{MgF2}$$ to explain a bond angle of 180 degrees (is this right?)? What about the crystal structure explained quantum mechanically?

Sorry if I ask too much in one shot.

• Sooo, you're asking mostly about NaF and MgF2 molecules? Well, they are just that - normal molecules, albeit highly polarised, so ionic contribution to bonds may be higher then covalent. Also you need quite high temp. to make them. Even after vaporisation there are dimers in gas phase. May 17 '20 at 23:28
• May 17 '20 at 23:30