Abstract
The different structures of lateral twin boundaries in spinel are shown to consist of a repeated triangular pyramid, or channel, defect, which when aligned parallel to certain planes gives the appearance of microfaceting. The channel defects were analysed experimentally by high-resolution electron microscopy and the images interpreted with the aid of a multislice, image-simulation program. It is shown that the channels are not empty but that they are regions of lower density. The differences between the lateral twin boundaries in spinel and the crystallographically similar interfaces in face-centered cubic metals are discussed.