Structure of Graphite

Abstract

Laidler and Taylor1 directed attention to the presence of lines in the X-ray diffraction photographs of graphite which could not be explained by the structure proposed by Bernal2, and by Hassel and Mark3: these lines are given by graphites from many different sources, natural and artificial. Similar extra lines on electron diffraction photographs of graphite had been observed by Finch and Wilman4. Edwards and Lipson5 thought that they may be caused by anomalies in the structure of graphite similar to those found in cobalt6, but occurring at regular intervals, and proposed a new structure which would account for these extra lines7. In this, the flat, honeycomb net planes are stacked parallel to each other, but instead of having the ababab sequence of the Bernal structure, they have an abcabc sequence: this gives a unit cell with a c-axis one and a half times the usual one. From intensity data they calculated that this new structure represented about 14 per cent of the graphite, the remainder being made up of 80 per cent of the ordinary structure and 6 per cent of a disordered structure. It is interesting to note that this new structure was the first structure suggested for graphite, by Debye and Scherrer8 in 1917.