An unprecedented C80 cage that violates the isolated pentagon rule

Two Lu2O@C80 isomers have been successfully isolated and unambiguously assigned as Lu2O@C1(31876)-C80 and Lu2O@C2v(5)-C80, respectively, by X-ray crystallography. Interestingly, C1(31876)-C80 is an unprecedented cage with a pair of adjacent pentagons, which can be closely connected with C2v(5)-C80via a two-step Stone–Wales transformation. More importantly, the C1(31876)-C80 cage is a key point in the transformation map of oxide cluster fullerenes, filling the vacancy in the formation process.