Question

Among the following species, Identify the isoelectronic and isostructural pair.

• A. $[N{F}_3,N{O}_3^{-}]$
• B. $[B{F}_3,N{O}_3^{-}]$
• C. $[B{F}_3,N{F}_3]$
• D. None of the above

Answer 1

The correct option is B $[B{F}_3,N{O}_3^{-}]$

Isoelectronic species have same number of electrons and Isostructural species have same hybridisation at the central atom.
Steric Number $\left(x\right)$ = $\frac{1}{2}\left(M+V-C+A\right)$.
where, M = number of monovalent surrounding atoms
V = number of valence electrons on the central atom
C = charge (with sign)
A=charge on anion

$N{F}_3$
$\text{number of electron}=7+9\times 3=34$
$\text{Steric Number (x)}=\frac{1}{2}(3+5-0+0)$.
$\text{Steric Number (x)}=4$.
Hybridisation =$s{p}^3$

$N{O}_3^{-}$
$\text{number of electron}=7+8\times 3+1=32$
$\text{Steric Number (x)}=\frac{1}{2}(0+5-0+1)$.
$\text{Steric Number (x)}=3$.
Hybridisation =$s{p}^2$


$B{F}_3$
$\text{number of electron}=5+9\times 3=32$
$\text{Steric Number (x)}=\frac{1}{2}(3+3-0+0)$.
$\text{Steric Number (x)}=3$.
Hybridisation =$s{p}^2$

$[B{F}_3,N{O}_3^{-}]$ are isoelectronic and isostructural pairs.