Ternary CBe4S32−/− Clusters: Fan-Shaped Global Minima with Planar Tetracoordinate Carbon

“Altering the auxiliary atoms” is an effective approach for expanding the planar tetracoordinate carbon (ptC) family. The ternary CBe4S32− cluster has been designed by using the “isoelectronic replacement of auxiliary bridges” strategy, based on previously reported ptC CBe4Cl3+. It possesses a fan-shaped structure, containing one ptC center, an arc-shaped Be4 ligand chain, and three auxiliary S bridges. The extensive search and high-level quantum chemistry calculations indicate that both ptC CBe4S32− and its derivative CBe4S3− are global minima structures on their potential energy surfaces. Born–Oppenheimer molecular dynamics simulations suggest that they also possess good dynamical stability. Chemical bonding analyses indicate that the ptC center in CBe4S32− is stabilized by one delocalized π bond and three delocalized σ bonds within the CBe4 core, while magnetically induced current density analysis reveals localized diatropic circulations without exhibiting a ring current. The current contribution introduces two new members to the ptC family, expanding the ptC bonding modes and design strategies.