A computational study of arsenic dicarbide (C2As)

A computational study of arsenic dicarbide has been carried out. In agreement with the experimental evidence theoretical calculations predict a 2Π ground state. However, a cyclic 2B2 species is found just about 3–4 kcal/mol higher in energy. The 2B2 species is shown to be a true minimum with a predicted barrier for isomerization around 7–8 kcal/mol. An analysis of the bonding suggests that the 2B2 state is a truly cyclic species. The preference for the linear arrangement appears to be due to weaker Pauli repulsion, since both electrostatic and orbital terms seem to favor the cyclic isomer.