The observation of forbidden reflections in V₃Si

Structurally forbidden Bragg maxima in the X-ray diffraction pattern of V₃Si have been observed. These reflections are excited by nonspherical electron distributions and anharmonic and anisotropic thermal motion. The forbidden reflections which are accessible to such excitation are correctly predicted by theory. Further studies of such maxima both with neutrons and X-rays should provide insights into the electronic and thermal behaviour of A15 compounds.