I was doing lewis structures and i came across a question asking the structure of POCl3. Here, the answer is a tetrahedral shape with P as central atom connected to 3Cl atoms by a single bond and 1 oxygen atom by a double bond. The valency of P is 3. So, it needs 3 electrons to get the nobel gas configuration and become stable so it could have formed single bonds with 2 cl atoms and single bond with an oxygen atom which would be single bonded to cl atom. Why isn't this structure correct?
And how can P form 4 bonds while it needs only 3? I think it's something related to D-orbital but if it undergoes sp3d hybridisation, it would need 5 bonds. Also, the structure of this compound is tetrahedral and hybridisation of P is sp3. How can this be? How can it form 4 bonds although it has only 3 unpaired electrons? Nitrogen couldn't form such compounds.
I googled about it and could find nothing but the hybridisation and lewis structure. My actual question isn't answered anywhere