Extra Rings in Graphite Electron Diffraction Patterns

Abstract

RECENTLY we have obtained transmission patterns from graphite powders in which prominent extra rings appear ; owing to insufficient resolution these have hitherto escaped notice. Two of these rings lie in a band comprising also the 100 and 101 diffractions (see Fig. 1), and others lie out beyond this region. These extra rings have been obtained from both natural and artificial graphite powders of high carbon content, and are therefore not due to impurities ; nor can they be ascribed to a Lennard-Jones surface lattice deviation effect, because the sharpness of the 110 ring negatives any such explanation. The dimensions of the extra rings and the manner in which they break up into arcs on inclining an orientated specimen in the beam shows that these rings are due to planes, the spacings of which have no counterpart in the structure assigned to graphite by X-rays.