^{S2- and S3-} centers in SrCl₂ single crystals are observed. The underlying experimental investigation is carried out by EPR, Raman, and optical absorption spectroscopy. The S₃^- centers show dynamical features in their EPR spectra. The temperature dependence of these spectra is compared with the results of the Kubo line shape theory. This enables to identify the motion as a thermally activated reorientation of the center between two equivalent equilibrium positions.