Frost Diagram For A 4-Sided Shape
Here's where things get a bit more complex than the Frost Diagrams we have been doing so far. The first few steps are the same as the others:
Now you'll notice here that our grey line dividing the circle in half goes through two of the points where the corners touch the circle. These cannot be classified as bonding or anti-bonding. They are non-bonding. This is signified with an "n":
When it comes to assigning the four valence electrons, we start with the bottom and put 2 on each line, like with the Benzene.
For the second layer - the non-bonding pi-bonds - we fill in the electrons one at a time, going back and forth between the two sides until they are used up. In this case, that leaves us with one electron in each one:
This is a highly unstable compound due to these non-bonding electrons.
This also makes it anti-aromatic.
