Question

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

• A. $\ce{ SO_3^{2-} , NO^-_3 }$
• B. $\ce{ ClO_3^- , SO_3^{2-} }$
• C. $\ce{CO_3^{2-} , SO_3^{2-} }$
• D. $\ce{ ClO^-_3 , CO_3^{2-}}$

Answer 1

Answer: (B)

Number of electrons
$\ce{ CO^{2-}_3 = 6 + 2 + 24 = 32}$
$\ce{SO^{2-}_3 = 16 + 2 + 24 = 42}$
$\ce{CIO^{-}_3 = 17 + 24 + 1 = 42}$
$\ce{CO^{2-}_3 = 6 + 24 + 2 = 32}$
$\ce{NO^{2-}_3 = 7 + 2 + 24 = 33 }$
Hence, $\ce{CIO^{-}_3}$ and $\ce{SO^{2-}_3}$ are isoelectronic and are pyramidal in shape.