▎ 摘　　要

In this brief report, we propose the ab initio prediction of a new polymer of carbon monoxide, previously overlooked in extensive searches for its phases. This polymer (named gamma-graphene monoxide) is more energetically favorable at ambient pressure than molecular CO, and possesses a set of unusual properties. Both first principles calculations and straightforward crystallochemistry analysis suggest that it is metallic at ambient pressure, and even superconducting with a critical temperature T-c = 4-20 K.