"So, last day, we talked about secondary bonding, and we looked at various forms of secondary bonding. Here's the cartoons, dipole-dipole interactions, dipole induced, dipole in solutions, a little bit of a diversion, induced dipole, induced dipole, which was the London dispersion forces, or van der Waals bonds, and also hydrogen bonding.

And, all of these helped us answer the question, what's the state of aggregation? The reason we want to know the state of aggregation is that this is solid-state chemistry. And we want to know when something is a solid.

So, this helps us get to that conclusion. And, then we came to the point where we realized that three quarters of the periodic table wasn't covered by either ionic bonding, covalent bonding, or van der Waals bonding as a primary form of bonding..."