Coincidence twist boundaries between crystalline smoke particles

Twist boundaries have been observed on {001} surfaces between crystals of MgO and CdO smoke. Measurements of the angles of twist across several hundred of these boundaries have revealed preferences for boundaries at 16.5°, 22.6°, and 37.3°in MgO and 22.8°, 28.5°, and 37.1°in CdO. These angles agree with those predicted by the coincidence site model to within the accuracy of measurement. © 1971 The American Institute of Physics.