Question

Which of the following species has a bond order other than $3$ ?

• A. $CO$
• B. $CN^-$
• C. $NO^+$
• D. $O^+_2$

Answer 1

Answer: (D)

$O^+_2$

Answer 2

It is a well-known fact that $N _{2}$ contains a triple bond between the two $N$ atoms. Therefore, molecules with a total of 14 electrons will have a bond order 3 . $e ^{-}( CO )=14$
$e ^{-}\left( CN ^{-}\right)=14$
$e ^{-}\left( NO ^{-+}\right)=14$
$e ^{-}\left( O _{2}^{+}\right)=15$
$\therefore O _{2}^{+}$has a bond order other than $3$.