Why is XeF4 molecule shape a square planer?

1 Answer
Jan 9, 2017

Answer:

This is a consequence of #"VSEPR theory"#, which correctly predicts the geometry of main group compounds...........

Explanation:

This is a consequence of #"Valence shell electron pair repulsion"# #"theory"#, which correctly predicts the geometry of main group compounds on the basis of the number of electron pairs around a central atom.

Around the central xenon atom there are #(8 + 4)# electrons, i.e. 6 electron pairs. The most energetically stable geometry around xenon is as an octahedron. And thus there are #4xx"Xe"-"F bonds"# in the plane, and 2 lone pairs of electrons, which are normal to the plane:

http://ts3.mm.bing.net/th?id=OIP.M338e31a5b8e1ac3162f030a3a9fb424ao0&pid=15.1&w=146&h=100&p=0

AS with all these problems, it is important to recognize that the electronic geometry is octahdedral. However, we describe the geometry on the basis of bonding pairs between atoms, not electron pairs. The geometry of #"AX"_4# thus descends to #"square planar"#.

I wish I could make the illustration bigger but I am a klutz with these grafix.