Draw the diagrams for ${NO}_{2}^{-}$ $"NO"_2^-$ , ${NO}_{2}^{+}$ $"NO"_2^+$ , and ${NO}_{2}$ $"NO"_2$ . The HOMO of ${NO}_{2}^{-}$ $"NO"_2^-$ shows it is somewhat anti-bonding. Would you expect the nonbonding electron pairs on nitrogen or oxygen to be more reactive? Discuss

Question

Draw the diagrams for ${NO}_{2}^{-}$ $"NO"_2^-$ , ${NO}_{2}^{+}$ $"NO"_2^+$ , and ${NO}_{2}$ $"NO"_2$ . The HOMO of ${NO}_{2}^{-}$ $"NO"_2^-$ shows it is somewhat anti-bonding. Would you expect the nonbonding electron pairs on nitrogen or oxygen to be more reactive? Discuss

1 Answer

Impact of this question

13504 views around the world

You can reuse this answer
Creative Commons License

Answer 1 · 2018-02-09T15:55:27

You've seen the molecular orbital (MO) diagram of ${CO}_{2}$ $"CO"_2$ :

Inorganic Chemistry, Miessler, Fischer, and Tarr, pg. 148

${CO}_{2}$ $"CO"_2$ and ${NO}_{2}^{+}$ $"NO"_2^+$ are isoelectronic and thus have the same electron configuration. Thus, simply add one or two electrons into the $2 b_{3 u}$ $2b_(3u)$ and $2 b_{2 u}$ $2b_(2u)$ to get ${NO}_{2}$ $"NO"_2$ and ${NO}_{2}^{-}$ $"NO"_2^-$ , respectively.

Nitrogen atom has $2 p$ $2p$ atomic orbitals lower by $2.52 eV$ $"2.52 eV"$ , and $2 s$ $2s$ atomic orbitals lower by $6.13 eV$ $"6.13 eV"$ than with carbon atom.

That makes the HOMO ( $1 b_{2 g}, 1 b_{3 g}$ $1b_(2g), 1b_(3g)$ ) belongs more so to nitrogen in ${NO}_{2}^{+}$ $"NO"_2^(+)$ than to carbon in ${CO}_{2}$ $"CO"_2$ . It also means the LUMO ( $2 b_{3 u}, 2 b_{2 u}$ $2b_(3u), 2b_(2u)$ ) is less antibonding in ${NO}_{2}^{+}$ $"NO"_2^(+)$ than in ${CO}_{2}$ $"CO"_2$ .

The nonbonding electron pairs on oxygen in ${NO}_{2}^{-}$ $"NO"_2^(-)$ should be more reactive...

The HOMO on ${NO}_{2}^{-}$ $"NO"_2^-$ are the ( $2 b_{3 u}, 2 b_{2 u}$ $2b_(3u), 2b_(2u)$ ) MOs, which are half-filled. Those are the lone pair on nitrogen.

The $4 a_{g}$ $4a_g$ is the LUMO then, and it belongs more to nitrogen than oxygen, as it is above nitrogen atom in energy, and nitrogen's atomic orbitals are above oxygen's in energy.

The $2 a_{g}$ $2a_g$ and $2 b_{1 u}$ $2b_(1u)$ nonbonding $σ$ $sigma$ orbitals, as well as the ( $1 b_{2 g}, 1 b_{3 g}$ $1b_(2g), 1b_(3g)$ ) $π$ $pi$ orbitals, belong more to oxygen than to nitrogen. Those are the lone pairs on the oxygens.

The lone pair on nitrogen is in $π$ $pi$ orbitals, meant for making $π$ $pi$ bonds. But the lone pairs on oxygen are in $σ$ $sigma$ AND $π$ $pi$ orbitals, meant for making $σ$ $sigma$ OR $π$ $pi$ bonds.

Hence, upon protonation, the $H^{+}$ $"H"^(+)$ goes onto the OXYGEN via the $σ$ $sigma$ orbitals $2 a_{g}$ $2a_g$ and $2 b_{1 u}$ $2b_(1u)$ , making $σ$ $sigma$ bonds.

![https://upload.wikimedia.org/]( useruploads.socratic.org )

Science

Math

Humanities

... and beyond

Draw the diagrams for ${NO}_{2}^{-}$ $"NO"_2^-$ , ${NO}_{2}^{+}$ $"NO"_2^+$ , and ${NO}_{2}$ $"NO"_2$ . The HOMO of ${NO}_{2}^{-}$ $"NO"_2^-$ shows it is somewhat anti-bonding. Would you expect the nonbonding electron pairs on nitrogen or oxygen to be more reactive? Discuss

1 Answer

Related questions

Impact of this question

Science

Math

Humanities

... and beyond

Draw the diagrams for "NO"_2^-NO−2"NO"_2^-, "NO"_2^+NO+2"NO"_2^+, and "NO"_2NO2"NO"_2. The HOMO of "NO"_2^-NO−2"NO"_2^- shows it is somewhat anti-bonding. Would you expect the nonbonding electron pairs on nitrogen or oxygen to be more reactive? Discuss

1 Answer

Related questions

Impact of this question

Draw the diagrams for ${NO}_{2}^{-}$ $"NO"_2^-$ , ${NO}_{2}^{+}$ $"NO"_2^+$ , and ${NO}_{2}$ $"NO"_2$ . The HOMO of ${NO}_{2}^{-}$ $"NO"_2^-$ shows it is somewhat anti-bonding. Would you expect the nonbonding electron pairs on nitrogen or oxygen to be more reactive? Discuss