"Powder" diffraction pattern of a crumpled (not quite powdered)
origami shell, using Cu Kα
radiation. The (002) peak at ~27.5˚, corresponds to a graphene layer
spacing of 0.32 nm, which is less than the 0.335 nm spacing we would expect of
ideal graphite[2]. Upon closer inspection,
the (002) peak is actually two distinct peaks, indicating the presence of two
distinct, compressed crystalline regions within the material.
![](xrd.ht2.gif)
This magnified view of the bifurcated (002) peak is evidence of
two distinct, compressed crystalline layers within a typical origami graphite
shell. The stress may be due to differential thermal contraction.
The origami structure forms at a temperature in excess of 1200˚C
and cools to room temperature before the XRD analysis. Although these
shells are pure graphite, a glance at the
origami page reveals why an origami shell may effectively be
composed of two dissimilar materials. The broad facets have a radial
orientation, while the narrow facets have a more tangential orientation.