Question

Which of the following pairs of ions are isoelectronic and isostructural?

• A. $Cl{O}_3{}^{-},S{O}_3^{2-}$
• B. $Cl{O}_3{}^{-},C{O}_3^{2-}$
• C. $C{O}_3^{2-},N{O}_3{}^{-}$
• D. $S{O}_3^{2-},N{O}_3{}^{-}$

Answer 1

The correct option is C $C{O}_3^{2-},N{O}_3{}^{-}$

$N{O}_3^{-}(5+3\times 6+1)=24$

$C{O}_3^{2-}$ have 24 electrons. $(4+3\times 6+2=24)$

Thus they have 24 electrons and hence are isoelectronic. Further, both $C{O}_3^{-}$ and $N{O}_3^{-}$ ions are planar and hence isostructural since-both $C$ and $N$ are $s{p}^2$ hybridized. They have trigonal planar geometry.