An ab initio study of antimony dicarbide (C2Sb)

Antimony dicarbide was investigated employing coupled cluster and multiconfigurational methods. The relativistic effects were taken into account by using pseudopotentials for the Sb atom; additional corrections due to all-electron correlations and spin–orbit effects were also included. C2Sb is found to be quasi-linear in the ground 2A″ [X 2Π] state with a very small barrier to linearity (0.07 kJ mol−1); T-shaped cyclic C2v (2B2) geometry was found just about 2.9 kJ mol−1 higher in energy. A molecular orbital analysis, spin–orbit constants, dissociation energies of C2Sb (X 2Π), and the low-lying excited valence-type electronic states are reported.