Delocalised electron in graphite

I have a question regarding the delocalised electron in graphite. There has been conflicting information between books.


Some books said the delocalised electron in graphite exists $\bf{between}$ layers.
Some said the delocalised electron in graphite exists $\bf{within}$ the hexagonal layer.


I support the second statement, because carbon has electronic configuration of 1s2 2s2 2p2. Graphite has sp2, therefore leaves 1 p orbital. And the giant pi bond should be extended over the layer, instead of between. 


I am not sure my evidence is sound.
Any advice would be greatly appreciated. Thank you in advance.




It's just a matter of definition. If a "layer" is understood as an infinitely thin plane passing through the centers of carbon atoms, then the electron density of the huge delocalized $\pi$ orbital is located above and below that plane, i.e., technically **between** layers. If a layer is defined so as to include whole atoms, then the said orbital is **within** layer.


In any case, the delocalized electrons are more or less "free" to move along the planes and **not** perpendicular to them, which explains the high anisotropy in electrical conductance and other properties of graphite.


 8