Determining the pi bonds in SOCl2

Question

The double bond in SOCl2 is comprised of a σ(sp³-sp²) bond and a π(3d-2p) bond. How do we know that it's a 3d and a 2p orbital that is left over to make a pi bond?

Answer 1

According to Lewis structure of SOCl₂:

The central atom S has total five pairs of electrons, two pairs form two single bond with two Cls, one double bond formed with oxygen (O=S) and plus one lone pair of electrons.

The electron configuration of oxygen is: [He]2s²2p⁴, and Sulfur is: [Ne]3s²3p⁴. For sulfur in three 3p orbitals, two 3p orbitals are used to form 2 single bonds with two Cls, and the 3s orbital is filled with the lone pair of electrons. The third 3p orbital is formed one σ bond with oxygen, and a 3d orbital is formed one π bond with oxygen. Therefore, by referring to the electron configurations of oxygen and sulfur, the double bond between O=S is comprised of a σ(sp³-sp²) bond and a π(3d-2p) bond.