What is Banana bond (3C-2e bridge bond) ? Explaine with suitable examples.

3C-2e BOND OR BANANA BOND:

EXAMPLE FORMATION OF B₂H₆:

(1) Formation of 3C-2e bond in B₂H₆ is best explain by MOT and total number of bond in B₂H₆ is 6 (3C-2e=2 and 3C-4e=4)

(2) Bridge bonds are longer than terminal bond because at bridge bonds electrons are delocalized at three centres

(3)  Bond energy (441kj/mole) of B-H-B bond is greater than bond energy (381 K j/mole) of   B-H bond.

(4) Hybridization of B atom is sp3, so non planer, and non polar (U=0)

(5)  B₂H₆ Methylated up to B₂H₂ Me₄

(6) B₂H₆ is hypovalent molecule hence act as Lewis acid and undergoes two type of cleavage when react with Lewis base

What is bridge bond ? explaine 3C-4e bridge bond with suitable examples .

 3C-4e BOND or 3C-4e BRIDGE BOND:

Al₂Cl₆ Dimmerised by 3C-4e bond bridge bond:

Al₂Cl₆ is neither hypovalent nor hypovalent rather its octet is complete. We will used  MOT here  it cannot act as Lewis acid  due to crowding in spite having vacant d orbital’s however Alcl₃ act as Lewis acid.

Al2Cl6 contains six bond having two bridge bond(3c-4e) and four bond is (2C-2e)

Boron do not formed bridge bond because boron experience steric crowding.

If silver iodide crystallizes in a zinc blende structure with I- ions forming the lattice then calculate fraction of the tetrahedral voids occupied by Ag+ ions.

In AgI, if there are nI^- ions, there will be nAg⁺ ions. As I^- ions form the lattice, number of tetrahedral voids = 2n. As there are nAg⁺ ions to occupy these voids, therefore fraction of tetrahedral voids occupied by Ag⁺ ions = n/2n = ½ = 50%.

Arrange the silicon halides into decreasing order of Lewis acids Character? SiF3, SiCl3, SiBr3, SiI3

In case of silicone halides inductive effect dominate over back bonding hence lewis acid character decided by inductive effect.

Hence order of lewis acid character   SiF₃ >SiCl₃ > SiBr₃ > SiI₃

What is the d-Orbital resonance ?

D-ORBITAL RESONANCE:
It is a phenomenon in which electrons of ms and np get delocalized to vacant nd orbital because this availability of vacant d orbital to expect back bond get reduced .
In those molecules species where d orbital’s resonance exist of back Bonding is decreased.