sp 3

sp ↿⇂ ↿⇂ ↿⇂ ↿⇂ Fig . sp Hybridisation : CH Unit Unit - - - - sp d Hybridisation: In the molecules such as PCl , the central atom phosphorus is covalently bound to five chlorine atoms. Here the atomic orbitals of phosphorous undergoes sp d hybridisation which involves its one 3s orbital, three 3p orbitals and one vacant 3d orbital (d z2 ). The ground state electronic configuration of phosphorous is [Ne]3s 3p x 3p y 3p z as shown below. Ground State E 3p x 3p y 3s ↿⇂ ↿ ↿ ↿ 3p z One of the paired electrons in the 3s orbital of phosphorous is promoted to one of its vacant 3d orbital (d z2 ) in the excite state. One 3s orbital, three 3p orbitals and one 3d z2 orbital of phosphorus atom mixes to give five equivalent sp d hybridised orbitals. The orbital geometry of sp d hybridised orbitals is trigonal bi-pyramidal as shown in the figure . . Overlap with 3p z orbitals of chlorine: The 3p z orbitals of the five chlorine atoms linearly overlap along the axis with the five sp d hybridised orbitals of phosphorous to form the five P-Cl σ-bonds, as shown below. Excited state 3d Z 3p 3p y 3p z 3s ↿ E ↿ ↿ ↿ ↿ Hybridised State sp d sp d sp d sp d sp d ↿ ↿ ↿ ↿ ↿ sp d Hybridisation sp d 3p z 3p z 3p z 3p z 3p z sp d sp d sp d sp d ↿⇂ ↿⇂ ↿⇂ ↿⇂ ↿⇂ Fig . sp d Hybridisation : PCl Unit Unit - - - - sp d Hybridisation: In sulphur hexafluoride (SF ) the central atom sulphur extend its octet to undergo sp d hybridisation to generate