Figure 5.

The ⁵⁷Fe Mössbauer spectra of 1 (A, left) and 2 (B, right) recorded on polycrystalline samples at 90 K. Both spectra exhibit a single quadrupole doublet, with δ = 1.13 mm/s, ΔE_Q = 1.88 mm/s, and Γ_R,L = 0.46 mm/s for 1 and δ = 0.43 mm/s, ΔE_Q = 1.35 mm/s, and Γ_R,L = 0.42 mm/s for 2. Least-squares fits (solid lines), assuming Lorenztian lineshapes, are overlaid on the experimental points.