Abstract
Based on the analysis of higher-order Laue zone diffraction by Bird (1985), the structure of the commensurate superlattice state of 2H-TaSe2 is determined by convergent-beam electron diffraction. It is shown that the most general displacements allowed by the orthorhombic space group can be described by a set of displacement waves. Only those waves with wavevector 1/3a* and Sigma 1 symmetry have significant amplitudes. The final displacement pattern shows that each layer is strongly orthorhombic, in contrast with some recent Landau theory predictions.