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 115°.

ONO
  • N
  • O
  • lone pair

NO₂⁻Nitrite ion

Bent

AB₂E: 2 bond pairs, 1 lone pair

  • Hybridisationsp²
  • Bond angleabout 115°
  • Polarityion, charge −1

Why this shape

  1. N has 5 valence electrons. It uses three in one double bond to O and one single bond to O, so two are left as one lone pair.
  2. Steric number = two sigma bonds + one lone pair = 3, so N is sp² hybridised. A double or triple bond counts once: only its sigma bond uses a hybrid orbital.
  3. Three electron pairs point to the corners of a flat triangle (trigonal planar electron geometry). With one lone pair in place of atoms, the atoms make a bent shape.
  4. Repulsion falls in the order lone pair to lone pair > lone pair to bond pair > bond pair to bond pair. The lone pair pushes the bond pairs closer, so the angle is about 115°, less than the ideal 120°.
  5. NO₂⁻ is an ion with an overall charge of −1, so it is not described as polar or non-polar.

Lewis structure

18 valence electrons, 2 resonance structures
NOO−
NOO−

Formal charges: O −1

Working

Why this hybridisation and shape

  1. N has 5 valence electrons. It uses three in one double bond to O and one single bond to O, so two are left as one lone pair.
  2. Steric number = two sigma bonds + one lone pair = 3, so N is sp² hybridised. A double or triple bond counts once: only its sigma bond uses a hybrid orbital.
  3. Three electron pairs point to the corners of a flat triangle (trigonal planar electron geometry). With one lone pair in place of atoms, the atoms make a bent shape.
  4. Repulsion falls in the order lone pair to lone pair > lone pair to bond pair > bond pair to bond pair. The lone pair pushes the bond pairs closer, so the angle is about 115°, less than the ideal 120°.
  5. NO₂⁻ is an ion with an overall charge of −1, so it is not described as polar or non-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. It uses three in one double bond to O and one single bond to O, so two are left as one lone pair. Steric number = two sigma bonds + one lone pair = 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 115 degrees. Three electron pairs point to the corners of a flat triangle (trigonal planar electron geometry). With one lone pair in place of atoms, the atoms make a bent shape. Repulsion falls in the order lone pair to lone pair > lone pair to bond pair > bond pair to bond pair. The lone pair pushes the bond pairs closer, so the angle is about 115°, less than the ideal 120°.

How many lone pairs are on the central atom of NO2-?

1 lone pair. N has 5 valence electrons. It uses three in one double bond to O and one single bond to O, so two are left as one lone pair.

Try any molecule