Pick out among the following, species isoelectronic with ${\mathrm{CO}}_2$.

The phrase "isoelectronic species," which means "same electric" or "equal charge," describes two atoms, ions, or molecules with the same electronic structure and the same amount of valence electrons.

No. of electron in ${\mathrm{CO}}_2,{\mathrm{N}}_3^{-},(\mathrm{CNO}{)}^{-},\left({\mathrm{NCN}}^{2-}\right.)$ are 22.