Fig. 3. Resonance Raman spectra of [Cr^V(¹⁶O)(6-COO^–-tpa)]²⁺ (red line), [Cr^V(¹⁸O)(6-COO^–-tpa)]²⁺ (blue line), and their differential spectrum (black line); measured at 236 K in CD₃CN with 441.6 nm excitation. The peaks marked with ‘S’ are ascribed to the bands due to the solvent.