Ionic Equilibrium Part 1

PCl5 has no lone-pair on the central atom but has empty d-orbital in valence shell, so that it can accept a pair of electrons (from a
Lewis acid Species which accepts a pair of electron in their vacant orbital e.g. BF3,AlCl3,PCl5.
Lewis base Species which can donate a pair of electron, e.g.

..

P

Cl3,

..

N

H3,

..

N

F3,:

..

Cl

F3,

..

S

F4.