# Why does Graphene have a higher melting point than Diamond?

I'm not 100% sure about this, so I just wanted to double-check.

I think it has something to do with each carbon atom in Graphene having a delocalized electron and this creates carbon ions that can exert an electrostatic attraction. This would reduce the inter-particle distances between carbon atoms in Graphene relative to Diamond, hence Graphene's higher melting point. But again, I'm not quite sure.

## 2 Answers

This is a poorly defined question. Melting is a change in stare, and it's based on thermodynamics. But at room pressure, neither diamond nor graphene are stable allotropes: graphite is. They are metastable.

So you start to mix in kinetics with the thermodynamics.

It's a bit like asking why does ice melt at a lower temperature than water.

If you look at the effects of pressure, then you can construct a phase diagram, and then the "melting" point of any given allotrope is defined by the boundary between solid and liquid.

Graphite(collection of graphene layers) has higher melting point than diamond, because of the partial double bond character of C-C bonds. So, the bond in each layer(graphene) is strong. Also, there are attractive forces between successive layers of graphene, increasing the melting point of Graphite

• So does Graphene form a resonance hybrid? – Tom Brooks Jan 1 '17 at 15:44