As carbon atoms form e.g. a graphite or diamond lattice,
the electronic orbitals hybridize.
It would be very hard to draw electronic densities in any
way that
the underlying lattice structure could be understood for tens of atoms in a
solid sample. So we draw different bonding states in different colors.
There are deep differences between diamond and graphite,
the former is a hard insulator, the latter a soft conductor.
sp2 orbitals -
3 in-plane nearest neighbours in sheets of
graphite,
near right.
4 nearest
neighbours in an sp3 bonded diamond lattice, far right.
As carbon atoms form e.g. a graphite or diamond lattice,
the electronic orbitals hybridize.
It would be very hard to draw electronic densities in any
way that
the underlying lattice structure could be understood for tens of atoms in a
solid sample. So we draw different bonding states in different colors. 