Creative Chemistry Molecular Models

The Octahedral Department

What is here?

You can see wireframe models of SF₆, IF₅ and ICl₄^–. Why have I chosen these?

All three molecules have six pairs of electrons around their central atom.
As a result, they all have an octahedral arrangment of electron pairs around the central atom.
The bond angle in sulphur hexafluoride, SF₆, is 90º.
Iodine pentafluoride, IF₅, contains a lone pair of electrons. Therefore, the electron pairs still have an octahedral arrangment, but because one of the axial atoms is "missing", the atoms have a square pyramidal arrangement. The bond angle is also 90º.
The ICl₄^– ion contains two lone pairs of electrons. Therefore, the electron pairs still have an octahedral arrangement, but because two of the axial atoms are "missing", the atoms have a square planar arrangement. The bond angle is again 90º.

The lone pairs of electrons show up as a small ball on these models. The molecules are animated, but if you want to stop them, right-click to bring up the menu and deselect Animate. Try using the left mouse button to turn the models around in different directions.
 

Molecular modelling applet courtesy of ChemAxon Ltd

(YOU CANNOT SEE A JAVA APPLET HERE)

back to top