Using large-scale basis sets and the B3LYP hybrid functional, the structures of linear and cyclic isomers of C6N have been studied. The lowest energy conformer is the linear. nitrogen-terminated structure in the (2)Pi electronic state. Surprisingly, the next lowest-lying isomer is a cyclic structure consisting of a cyclopropane ring and a C3N chain. The ionization energy, electron affinity. and equilibrium dipole moment for the linear ground state are 9.07 eV 3.55 eV, and 0.69 D. respectively. Harmonic frequencies were determined for the lowest energy structures. In the linear ground-state clusters. the bonding tends toward cumulenic, rather than polyacetylenic as in the odd-carbon molecules of similar length.