Identifying a Needle in a Haystack: Isolation and Structural Characterization of Er₂C₉₄ as the Carbide Er₂C₂@D₃(85)‐C₉₂

Abstract

A method has been developed for isolating a pure sample of Er C from the myriad of fullerenes and endohedral fullerenes that are formed in the electric arc process. Crystallographic analysis of Er C in a cocrystal formed with Ni(OEP) reveals that the molecule is the carbide Er C @D (85)-C . Crystals of Er C @D (85)-C ⋅Ni(octaethylporphyrin)⋅2 C H are isostructural with those of Sm @D (85)-C ⋅Ni(octaethylporphyrin)⋅2 (chlorobenzene). Comparisons are made between the four crystallographically characterized endohedrals (Er C @D (85)-C , Gd C @D (85)-C , La C @D (85)-C , and Sm @D (85)-C ) that utilize the chiral D (85)-C cage.

Crystallographic characterization of Lu2C2n (2n = 76–90): cluster selection by cage size

“…A more recent study reported the isolation and crystallographic elucidation of an Er-based CCMF, i.e. Er 2 C 2 @ D 3 (85)-C 92 , confirming again that larger cages tend to accommodate the carbide cluster 60. Moreover, for the even larger La 3+ ions, although the structures of some di-EMFs, namely La 2 @ D 2 (10611)-C 72 ,61 La 2 @ C s (17490)-C 76 ,62 La 2 @ D 3h (5)-C 78 ,63 La 2 @ I h (7)-C 80 ,64 and La 2 @ D 5 (450)-C 100 65 have been confirmed by single crystal XRD crystallography, the La 3+ ions are also more inclined to form carbide structures with some giant cages such as C 90–104 , which are rationalized by considering the synergistic effect of inserting a C 2 -unit on the stabilization of CCMFs both electronically and geometrically 47–49…”