Pulsed neutron diffraction results are presented for a series of activated
carbons with a variable microporosity. The results cover a wide Q-range ext
ending up to 50 Angstrom(-1) and enable the pair correlation function to be
evaluated with good spatial resolution. The diffraction pattern shows a br
oad oscillatory behaviour representative of a highly defective crystal stru
cture and differs considerably from graphite. Detailed investigation shows
that the local atomic structure is similar to that of graphite and exhibits
the expected hexagonal network but that the first peak arising from the ca
rbon-carbon bond has two components, indicating a quinoidal distortion of t
he network. The correlation length within the graphene sheet is short range
d and the inter-layer spacing also displays some disorder with an increased
spacing compared with graphite. The data provide a good basis for the deta
iled modelling of the structure and exhibit characteristics that could not
have been easily observed by other techniques.