Numford
Hybridisation

Hybridisation of SOCl₂

S is sp³ hybridised (hybridization by the VSEPR count): 3 sigma bonds and 1 lone pair give a trigonal pyramidal shape, bond angle less than 109.5°.

ClClSO
  • S
  • O
  • Cl
  • lone pair

SOCl₂Thionyl chloride

Trigonal pyramidal

AB₃E: 3 bond pairs, 1 lone pair

  • Hybridisationsp³
  • Bond angleless than 109.5°
  • Polaritypolar

Why this shape

  1. S has 6 valence electrons. It uses four in one double bond to O and two single bonds to Cl, so two are left as one lone pair.
  2. Steric number = three sigma bonds + one lone pair = 4, so S is sp³ hybridised. A double or triple bond counts once: only its sigma bond uses a hybrid orbital.
  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. 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 less than 109.5°, less than the ideal 109.5°.
  5. The bond dipoles do not cancel in the trigonal pyramidal shape, so SOCl₂ is polar.

Lewis structure

26 valence electrons
SOClCl

Formal charges: none

Working

Why this hybridisation and shape

  1. S has 6 valence electrons. It uses four in one double bond to O and two single bonds to Cl, so two are left as one lone pair.
  2. Steric number = three sigma bonds + one lone pair = 4, so S is sp³ hybridised. A double or triple bond counts once: only its sigma bond uses a hybrid orbital.
  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. 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 less than 109.5°, less than the ideal 109.5°.
  5. The bond dipoles do not cancel in the trigonal pyramidal shape, so SOCl₂ is polar.

Class 11, Chapter 4 Chemical Bonding and Molecular Structure.

Questions

Hybridisation of SOCl2: quick answers

What is the hybridisation of SOCl2?

S has 6 valence electrons. It uses four in one double bond to O and two single bonds to Cl, so two are left as one lone pair. Steric number = three sigma bonds + one lone pair = 4, so S is sp³ hybridised. A double or triple bond counts once: only its sigma bond uses a hybrid orbital.

What is the shape of SOCl2 and its bond angle?

Trigonal pyramidal, with a bond angle of less than 109.5 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. 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 less than 109.5°, less than the ideal 109.5°.

Is SOCl2 polar or non-polar?

Polar. The bond dipoles do not cancel in the trigonal pyramidal shape, so SOCl₂ is polar.

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