4.9 Problem

[Swetha Sundaram 1E]

For the molecule ICl3 can someone please explain to me why its molecular shape is T-shaped and not trigonal planar?

[Clara Hu 1G]

For ICl3, there are 5 regions of electron density, but only 3 are occupied by atoms, so there are two lone pairs, which means that it is T shaped.

[Rain Taganas 1J]

Because there are five regions of electron density (three bonded atoms and two lone pairs), the electron geometry for ICL₃ is trigonal bipyramidal. Since there are two lone pairs, it takes the positions on the equatorial axis instead of the axial axis (which is where your confusion occurs). Hence, the molecular geometry of ICL₃ is T-shaped.

[Manasvi Paudel 1A]

It is T shaped because the lone pairs are not taken into account when naming. That means there are three attached atoms.

[Swetha Sundaram 1E]

Well if the lone pairs weren't taken into account then it could just be trigonal planar but I think those two extra lone pairs on the iodine cause the chloride ions to have a bond angle of 90 degrees rather than 120 degrees.