Backbonding in molecules like BF3 Can anyone please briefly explain to me the concept of backbonding along with necessary conditions for backbonding with some example? As I understand, backbonding is a donation of electron from electron-rich to vacant orbital, but I don't know anything else.
$\ce{BF3}$ has trigonal plannar structure all the three $\ce{B-F}$ bonds lie in plane and thus p-orbitals of boron and fluorine become parallel.

Boron has empty p-orbital and p-orbital of fluorine contains lone pair, and hence  boron acts as Lewis acid and fluorine as Lewis base. Fluorine donates its lone pair to boron and this bonding is called backbonding.