Question

Which one of the following is the electron deficient molecule?

• A. $B_2{H}_6$
• B. $C_2{H}_6$
• C. $P{H}_3$
• D. $Si{H}_4$

Answer 1

The correct option is A $B_2{H}_6$

$B_2{H}_6$ is electron deficient molecule because boron atom has three half-filled orbitals in an excited state. The structure of $B_2{H}_6$ is represented as follows :

In it, two electrons of B-H bond are involved in the formation of three centre bond, these bonds are represented by a dotted line.

Hence, option $A$ is correct.