An x‐ray standing wave investigation of the structure of a high‐quality mosaic crystal of Cd0.725Mn0.275Te reveals that the Cd and Mn cations occupy the same sublattice in this zinc‐blende material, as expected. This conclusion is made by inspection of the data obtained from a simple measurement made at the Cornell high energy synchrotron source. Furthermore, these data clearly indicate that the two cations have slightly different positions within the cation sublattice. Fitting these data to a simple model using x‐ray dynamical diffraction theory shows that these distinct cation positions are consistent with the bimodal CdTe and MnTe bond lengths previously observed with extended x‐ray absorption fine structure spectroscopy [A. Balzarotti, M. Czyzyk, A. Kisiel, N. Motta, M. Podgorny, and M. Zimnal‐Starnawska, Phys. Rev. B30, 2295 (1984)], but contradict the assertion that the cation sublattice is undistorted. This application of the standing wave technique to a mosaic crystal demonstrates that dynamical diffraction methods can produce important structural information from a much larger class of crystals than previously considered.