Weak-beam electron microscopy was applied to the study of the dissociation of dislocations in type-IIa diamond. Dislocations with a Burgers vector of ½[110] on (111) glide planes were found to be dissociated into two Shockley partials, with separations of between 2.5 and 4.3nm. Extended nodes and dissociated dipoles were also observed. The stacking-fault energy was determined, from the mean and distribution of the separations of the partials, to be 279mJ/m2. The behavior of dislocations in diamond appeared to be similar to that of dislocations in Ge and Si. Dissociation of Dislocations in Diamond. P.Pirouz, D.J.H.Cockayne, N.Sumida, P.Hirsch, A.R.Lang: Proceedings of the Royal Society A, 1983, 386[1791], 241-9