The Raman spectra of eight clinopyroxenes synthesized along the join diopside-clinoenstatite (DiCen, CaMgSi2O6-Mg2Si2O6) were measured. The splitting of the 670 cm–1 mode of the Ag symmetry,
observed in the composition Di52En48 to clinoenstatite, was interpreted as evidence of a C2/c-P21/c phase
transition. The transition was also revealed by deviation from the linear dependence of the peak position
vs. composition and by the appearance of several new peaks in the samples richer in clinoenstatite.