The structures of trimetallic nitride fullerenes M3N@C88: Theoretical evidence of corporation between electron transfer interaction and size effect

► Both Lu3N@C88 and Gd3N@C88 share the same parent cage C88:81738-D2. ► The parent cage is Cs symmetric C88:81734 for La3N@C88. ► Both electronic configuration and geometrical structure determine the structures and stability of M3N@C88.