Numford
Hybridisation

Hybridisation of NO₂

N is sp² hybridised (hybridization by the VSEPR count): 2 sigma bonds and 1 lone pair give a bent shape, bond angle about 134°.

ONO
  • N
  • O
  • odd electron

NO₂Nitrogen dioxide

Bent

AB₂E: 2 bond pairs, 1 odd electron

  • Hybridisationsp²
  • Bond angleabout 134°
  • Polaritypolar

Why this shape

  1. N has 5 valence electrons. In the Lewis structure it makes one double bond to O and one single bond to O and keeps no lone pair and one odd electron, which leaves it a formal charge of +1.
  2. Steric number = two sigma bonds + one odd electron = 3, so N is sp² hybridised. A double or triple bond counts once: only its sigma bond uses a hybrid orbital.
  3. Three electron domains point to the corners of a flat triangle (trigonal planar electron geometry). With one odd electron in place of atoms, the atoms make a bent shape.
  4. N has a single unpaired electron, not a lone pair. One electron repels the bonds less than a pair would, so the bond pairs push each other open to about 134 degrees.
  5. The bond dipoles do not cancel in the bent shape, so NO₂ is polar.

Lewis structure

17 valence electrons, 2 resonance structures
i

An odd electron molecule: 17 valence electrons, so N has only seven around it.

NOO+−
NOO+−

Formal charges: N +1, O −1

Working

Why this hybridisation and shape

  1. N has 5 valence electrons. In the Lewis structure it makes one double bond to O and one single bond to O and keeps no lone pair and one odd electron, which leaves it a formal charge of +1.
  2. Steric number = two sigma bonds + one odd electron = 3, so N is sp² hybridised. A double or triple bond counts once: only its sigma bond uses a hybrid orbital.
  3. Three electron domains point to the corners of a flat triangle (trigonal planar electron geometry). With one odd electron in place of atoms, the atoms make a bent shape.
  4. N has a single unpaired electron, not a lone pair. One electron repels the bonds less than a pair would, so the bond pairs push each other open to about 134 degrees.
  5. The bond dipoles do not cancel in the bent shape, so NO₂ is polar.

Class 11, Chapter 4 Chemical Bonding and Molecular Structure.

Questions

Hybridisation of NO2: quick answers

What is the hybridisation of NO2?

N has 5 valence electrons. In the Lewis structure it makes one double bond to O and one single bond to O and keeps no lone pair and one odd electron, which leaves it a formal charge of +1. Steric number = two sigma bonds + one odd electron = 3, so N is sp² hybridised. A double or triple bond counts once: only its sigma bond uses a hybrid orbital.

What is the shape of NO2 and its bond angle?

Bent, with a bond angle of about 134 degrees. Three electron domains point to the corners of a flat triangle (trigonal planar electron geometry). With one odd electron in place of atoms, the atoms make a bent shape. N has a single unpaired electron, not a lone pair. One electron repels the bonds less than a pair would, so the bond pairs push each other open to about 134 degrees.

Is NO2 polar or non-polar?

Polar. The bond dipoles do not cancel in the bent shape, so NO₂ is polar.

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