In which of the following molecules, sigma bonds formed by the overlap of sp3d and p-orbitals are absent

perchlorate ionClO4- - Perchlorate ionNo of electron pairs  = 1/2 [V + M - C + A]V = No of valency electronsM = No of monovalent atoms bonded to central atomC = Total charge on cationA = Total charge on anionClO4- :-Hybridisation = 1/2 [7 + 0 - 0 + 1]Hybridisation = 8/2 = 4 ⇒ sp3 - hybridisation:. Cl in ClO4- uses sp3 hybrid orbitals.OR