Extended Data Fig. 4: Calorimetry and thermogravimetric analysis of C₆₀ polymers.

a, DSC traces of (Mg₄C₆₀)_∞ and graphullerite crystals. The heat flow was measured as a function of temperature at a constant temperature ramp of 10 °C min^–1 during heating and 5 °C min^–1 during cooling with a 50 ml /min⁻¹ nitrogen cell purge flow. b, Weight loss as a function of temperature for molecular C₆₀ and (Mg₄C₆₀)_∞ under N₂ at a constant temperature ramp of 10 °C min^–1, measured by TGA. The 6% increase in the (Mg₄C₆₀)_∞ data is presumably due to the formation of MgO.