Numford
Hybridisation

Hybridisation of NF₃

N is sp³ hybridised (hybridization by the VSEPR count): 3 sigma bonds and 1 lone pair give a trigonal pyramidal shape, bond angle about 102°.

FFNF
  • N
  • F
  • lone pair

NF₃Nitrogen trifluoride

Trigonal pyramidal

AB₃E: 3 bond pairs, 1 lone pair

  • Hybridisationsp³
  • Bond angleabout 102°
  • Polaritypolar

Why this shape

  1. N has 5 valence electrons. It uses three in three single bonds to F, so two are left as one lone pair.
  2. Steric number = three sigma bonds + one lone pair = 4, so N is sp³ hybridised.
  3. Four electron pairs point to the corners of a tetrahedron (tetrahedral electron geometry). With one lone pair in place of atoms, the atoms make a trigonal pyramidal shape.
  4. F pulls the bond pairs away from N, so they repel each other less than in NH3 and the angle closes to about 102 degrees.
  5. It is polar, but much less than NH3: the N-F bond dipoles point away from the lone pair and partly cancel its moment. NCERT compares the two.

Lewis structure

26 valence electrons
NFFF

Formal charges: none

Working

Why this hybridisation and shape

  1. N has 5 valence electrons. It uses three in three single bonds to F, so two are left as one lone pair.
  2. Steric number = three sigma bonds + one lone pair = 4, so N is sp³ hybridised.
  3. Four electron pairs point to the corners of a tetrahedron (tetrahedral electron geometry). With one lone pair in place of atoms, the atoms make a trigonal pyramidal shape.
  4. F pulls the bond pairs away from N, so they repel each other less than in NH3 and the angle closes to about 102 degrees.
  5. It is polar, but much less than NH3: the N-F bond dipoles point away from the lone pair and partly cancel its moment. NCERT compares the two.

Class 11, Chapter 4 Chemical Bonding and Molecular Structure.

Questions

Hybridisation of NF3: quick answers

What is the hybridisation of NF3?

N has 5 valence electrons. It uses three in three single bonds to F, so two are left as one lone pair. Steric number = three sigma bonds + one lone pair = 4, so N is sp³ hybridised.

What is the shape of NF3 and its bond angle?

Trigonal pyramidal, with a bond angle of about 102 degrees. Four electron pairs point to the corners of a tetrahedron (tetrahedral electron geometry). With one lone pair in place of atoms, the atoms make a trigonal pyramidal shape. F pulls the bond pairs away from N, so they repel each other less than in NH3 and the angle closes to about 102 degrees.

Is NF3 polar or non-polar?

Polar. It is polar, but much less than NH3: the N-F bond dipoles point away from the lone pair and partly cancel its moment. NCERT compares the two.

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