# Van der Waals'

1. ### geoffreythelm

11
1. The problem statement, all variables and given/known data

2. Relevant equations

3. The attempt at a solution

I think Graphite is a Van der Waals' Solid and, er, salt would be an ionic.
But I really don't have much of a clue about what the second part is going on about!

Thanks! :)

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Last edited by a moderator: Aug 13, 2009
2. ### jpreed

36
Can't see the attachment yet. While Coulomb interaction dominate the interplay between electrons in graphite, I do believe the force holding the layers together could be referred to as van der Waals.

3. ### Fightfish

677
The second part is asking you for the variation of potential (attractive term) with respect to the distance between the particles, so for the van der Waals' forces, the Lennard-Jones potential applies, while for the ionic forces, the Coulomb potential applies. This would give $$\beta$$ as 6 for the former and 1 for the latter.