Abstract
Deformation twins have been observed in the intermetallic compound Cu2Sb. The theory of Bevis and Crocker (1968) has been applied to calculate, using a computer program, possible twinning modes in the tetragonal lattice of Cu2Sb. Twins in five separate crystals have been studied by two-surface methods in order to estimate the composition plane and angle of shear. The measurements are consistent with the operative twinning system being that mode predicted with the lowest shear. This mode has the elements K 1 =(112),η2 = [lll].