A computational study of arsenic dicarbide has been carried out. In agreement with the experimental evidence theoretical calculations predict a (2)Pi ground state. However, a cyclic B-2(2) species is found just about 3-4 kcal/mol higher in energy. The B-2(2) 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 B-2(2) 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. (C) 2009 Elsevier B.V. All rights reserved.