A comparison of vacancy and interstitial loops in graphite

A recent letter by Amelinckx and Delavignette (1960) suggested the possibility of distinguishing between interstitial and vacancy loops in graphite because the vacancy loop has a component of its Burgers vector in the basal plane whereas the interstitial loop has a Burgers vector parallel to the C axis. Independent work carried out in the Department of Metallurgy, Cambridge, has proved that this is so and has also produced positive evidence for Amelinckx's interpretation of the Burgers vector of the vacancy loops.