Find the number of molecules which have odd electron bond in its structure

${\mathrm{NO}}_2,\mathrm{NO},{\mathrm{ClO}}_2,{\mathrm{ClO}}_3,\mathrm{OF},{\mathrm{O}}_2^{-}$

Odd electron bond means there is an odd number of the electron in the overall molecule.

So, the molecules $\mathrm{NO},{\mathrm{ClO}}_2,{\mathrm{O}}_2^{-}$ have odd electron bond in its structure