Direct imaging of intracage structure in titanium-carbide endohedral metallofullerene

The Ti2C2 intracage structures are unambiguously visualized in the single-molecule images of titanium-carbide endofullerene (Ti2C2)@C-78 by high-resolution transmission electron microscopy (HR-TEM). At least two configurations of Ti2C2 are predicted for the energetically favorable (Ti2C2)@C-78 isomers by the density functional theory calculations, and found to show quite good agreement with the observed HR-TEM images.