An EPR study of Cr3+:K2SbF5

A single crystal X‐band EPR study of chromium (III) in the matrix K₂SbF₅ is reported, and five chromium sites are characterized. Two pairwise related sites with $g_z{\text{=1.9717± 0.0006,\hspace{0.17em}g}}_x{\mathrm{=g}}_y\text{=1.9744± 0.0006,\hspace{0.17em}D=0.2750± 0.0002\hspace{0.17em}}{\mathrm{cm}}^{\text{−1}}\text{,\hspace{0.17em}E=0.00836± 0.00007\hspace{0.17em}}{\mathrm{cm}}^{\text{−1}}$ markedly predominate and can be associated with a six‐coordinate species. The optical spectrum of the Cr³⁺:K₂SbF₅ system is correlated with the magnetic resonance behavior of the predominating sites with an empirical ligand field calculation assuming D₃ symmetry. A site present in very low concentrations can perhaps be associated with a five‐coordinate species, a symmetry characteristic of the antimony site in the K₂SbF₅ matrix.