Thermochemical properties of C₆₀Br₂₄

Abstract

The thermal decomposition of C₆₀Br₂₄•2Br₂ has been studied by Differential Scanning Calorimetry (DSC) at different heating rates. Depending from the heating rate, the thermal decomposition peak occurred between 163 °C and 201 °C with an activation energy E^# = 108.6 kJ/mol. The decomposition products are C₆₀ (assessed by FT-IR) and molecular bromine. From the decomposition enthalpy measured by DSC, the enthalpy of formation ΔH_f°(C₆₀Br_24(c)) = 2114 ± 34 kJ/mol has been determined. By group increment or group additivity method ΔH_f°(C₆₀Br_{24 (g)}) = 2184 kJ/mol has been calculated, in fair agreement with the experimental value. Furthermore, through the group increment method ΔG_f°(C₆₀Br_{24 (g)}) = 3264 kJ/mol has been estimated. The enthalpy of the C-Br bond in the C₆₀Br₂₄ molecule was found comprised between 108 and 120 kJ/mol.

Keywords:

• Thermochemistry
• C₆₀Br₂₄
• enthalpy of formation
• thermal decomposition
• group increment calculations

Additional information

Funding

We acknowledge support from State Research Agency (AEI) of the Spanish Ministry of Science and Innovation (MICINN) under grant PID2020-115758GB-I00. This article is based upon work from COST Action NanoSpace, CA21126, supported by COST (European Cooperation in Science and Technology).