(A-p,q,r) :(B-p,q,r,s) (c-p,q,r):(D-p).
(A) CO stronger field ligand comples for pairing of electrons and so `sp^(3)` hybridissation and diamagnetic. Ligand is two electon donor.
(B) When NO molecule co-ordinates with metal atom to from metallic nitrosyls, the single electron present in `pi**` antibonding molecular orbital is transferred to metal atom M so that NO molecules is converted into `NO^(+)` since `NO^(+)` is isoelectronic with CO molecule, this ion coordinated with M ion as a two electron donor in metal nitrosyls in the same way as CO coordinatr to M atom in metal carbonyls.Note than NO molecule is a three electron donor. Now the empty `pi**` antibonding molecular orbital can overlap with the filled d-orbital of metal from `M^(-)toNO^(+)pi` bond.
(C) `[Ni(PF_(3))_(4)]` has bonding like that of `[Ni(PF_(4))]`
