hybridisation of PCl3 should be sp^3 but it is sp^3d and in case of SF6 ot should be sp^3d but it is sp^3d^2 why is it so??
Please help
The exact shape of the molecule depends upon the total number of electron pairs present around the central metal atom., that is Bond pairs + lone pairs.
In SF6 , the central metal atom, sulfur(16), has the ground state electronic configuration :
S= 1s2 2s2 2p6 3s2 3px2 3py1 3pz1.
F= 1s2 2s2 2px2 2py2 2pz1
In excited state, one of the 3s electron as well as 3p electron get promoted to 3d orbitals(because sulfur has vacant d-orbital) giving the electronic configuration :
1s2 2s2 2p6 3s1 3px1 3py1 3pz1 3d1 3d1
This involves sp3d2 hybridisation.
Shape is Octahedral.
In PCl3, the central metal atom , phosphorus(15) ,has the ground state electronic configuration:
1s2 2s2 2p6 3s2 3px1 3py1 3pz1.
In excited state, one of the 3s electron gets promoted to 3d orbital giving electronic configuration
1s2 2s2 2p6 3s1 3px1 3py1 3pz1 3d1
Thus it involves sp3d hybridization, not sp3 . But Only 3 Cl atom are present, so 2 lone pair are present giving it a T- shape.
In SF6 , the central metal atom, sulfur(16), has the ground state electronic configuration :
S= 1s2 2s2 2p6 3s2 3px2 3py1 3pz1.
F= 1s2 2s2 2px2 2py2 2pz1
In excited state, one of the 3s electron as well as 3p electron get promoted to 3d orbitals(because sulfur has vacant d-orbital) giving the electronic configuration :
1s2 2s2 2p6 3s1 3px1 3py1 3pz1 3d1 3d1
This involves sp3d2 hybridisation.
Shape is Octahedral.
In PCl3, the central metal atom , phosphorus(15) ,has the ground state electronic configuration:
1s2 2s2 2p6 3s2 3px1 3py1 3pz1.
In excited state, one of the 3s electron gets promoted to 3d orbital giving electronic configuration
1s2 2s2 2p6 3s1 3px1 3py1 3pz1 3d1
Thus it involves sp3d hybridization, not sp3 . But Only 3 Cl atom are present, so 2 lone pair are present giving it a T- shape.