Synthesis and Single-Crystal X-ray Structure of a Highly Symmetrical C$_{60}$ Derivative, C$_{60}$Br$_{24}

C$_{60}$ and liquid bromine react to form C$_{60}$Br$_{24}$, a crystalline compound isolated as a bromine solvate, C$_{60}$Br$_{24}$(Br$_2$)$_x$. The x-ray crystal structure defines a new pattern of addition to the carbon skeleton that imparts a rare high symmetry. The parent C$_{60}$ framework is recognizable in C$_{60}$Br$_{24}$, but sp$^3$ carbons at sites of bromination distort the surface, affecting conformations of all of the hexagonal and pentagonal rings. Twenty-four bromine atoms envelop the carbon core, shielding the 18 remaining double bonds from addition. At 150° to 200°C there is effectively quantitative reversion of C$_{60}$Br$_{24}$ to C$_{60}$ and Br$_2$.