Numford
Hybridisation

Hybridisation of ICl₄⁻

I is sp³d² hybridised (hybridization by the VSEPR count): 4 sigma bonds and 2 lone pairs give a square planar shape, bond angle 90°.

ClClIClCl
  • I
  • Cl
  • lone pair

ICl₄⁻Tetrachloroiodate ion

Square planar

AB₄E₂: 4 bond pairs, 2 lone pairs

  • Hybridisationsp³d²
  • Bond angle90°
  • Polarityion, charge −1

Why this shape

  1. I has 7 valence electrons. In the Lewis structure it makes four single bonds to Cl and keeps two lone pairs, which leaves it a formal charge of −1.
  2. Steric number = four sigma bonds + two lone pairs = 6, so I is sp³d² hybridised.
  3. Six electron pairs point to the corners of an octahedron (octahedral electron geometry). With two lone pairs in place of atoms, the atoms make a square planar shape.
  4. The two lone pairs sit opposite each other, 180 degrees apart, so their repulsion is least and the four bonds lie in a square.
  5. The lone pairs balance each other, so the bonds are not pushed out of place and the angle stays at 90°.
  6. ICl₄⁻ is an ion with an overall charge of −1, so it is not described as polar or non-polar.

Lewis structure

36 valence electrons
IClClClCl−

Formal charges: I −1

Working

Why this hybridisation and shape

  1. I has 7 valence electrons. In the Lewis structure it makes four single bonds to Cl and keeps two lone pairs, which leaves it a formal charge of −1.
  2. Steric number = four sigma bonds + two lone pairs = 6, so I is sp³d² hybridised.
  3. Six electron pairs point to the corners of an octahedron (octahedral electron geometry). With two lone pairs in place of atoms, the atoms make a square planar shape.
  4. The two lone pairs sit opposite each other, 180 degrees apart, so their repulsion is least and the four bonds lie in a square.
  5. The lone pairs balance each other, so the bonds are not pushed out of place and the angle stays at 90°.
  6. ICl₄⁻ 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 ICl4-: quick answers

What is the hybridisation of ICl4-?

I has 7 valence electrons. In the Lewis structure it makes four single bonds to Cl and keeps two lone pairs, which leaves it a formal charge of −1. Steric number = four sigma bonds + two lone pairs = 6, so I is sp³d² hybridised.

What is the shape of ICl4- and its bond angle?

Square planar, with a bond angle of 90 degrees. Six electron pairs point to the corners of an octahedron (octahedral electron geometry). With two lone pairs in place of atoms, the atoms make a square planar shape. The two lone pairs sit opposite each other, 180 degrees apart, so their repulsion is least and the four bonds lie in a square. The lone pairs balance each other, so the bonds are not pushed out of place and the angle stays at 90°.

How many lone pairs are on the central atom of ICl4-?

2 lone pairs. I has 7 valence electrons. In the Lewis structure it makes four single bonds to Cl and keeps two lone pairs, which leaves it a formal charge of −1.

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