Sc2S@C74: Linear metal sulfide cluster inside an IPR-violating fullerene

To identify the structures and understand the stability mechanism of the detected metal sulfide fullerene Sc2S@C74, we performed a systematic density functional theory study on the isomers of C74 with 0–3 B55 bonds and 35 candidate isomers of Sc2S@C74. The results demonstrate that Sc2S@C74 violates the isolated pentagon rule and its cage has two B55 bonds, the transferred electrons from Sc2S cluster stabilize the active cage (C74:13 333). Sc2S is linear inside the cage and significantly different from those of Sc2S@C72 and Sc2S@C82. The calculations demonstrate that it is highly favored for Sc2S cluster to be encaged inside (C74:13 333).