Fig. 7. Selected SMMs with metal–metal bonds. (a) Magnetic relaxation times for Tb₂@C₈₀-CF₃ in a zero field and a 0.2 T dc field, along with the molecular structure and spin density (DFT-computed for the Y derivative) in the inset. (b) Magnetic hysteresis loops for Tb₂@C₈₀-CF₃. Adapted (a and b) with permission from ref. 83; copyright: (2021) American Chemical Society. (c) Magnetic relaxation times for [(Cp^iPr5)₂Ln₂I₃], along with the molecular structure in the inset. (d) Field-cooled demagnetization and magnetic hysteresis loops for [(Cp^iPr5)₂Dy₂I₃] at a field sweep rate of 0.01 T s⁻¹, along with the spin density (CASSCF-computed for the Gd derivative) in the inset. Adapted (c and d) with permission from ref. 86; copyright: (2022) The American Association for the Advancement of Science. The different shapes of the distributions of spin density (between a and d) should be particularly noted.