Carbon Suboxide, CO: A Hidden σπ Carbene.

Electronic structure of carbon suboxide, CO, has been recently described as OC→C←CO having two lone pairs at the central carbon atom, thereby called as "Carbones". Although it has a linear geometry, the presence of two lone pairs comes to fore when its reactivity is analyzed with two protons. However, no attention had been paid on its alternating reactivity with hydride ions. Herein, detailed quantum chemical calculations predict that carbon suboxide can also have significant hydride ion affinity. This reactivity is in tune with σπ carbene character of carbon suboxide. This study also shows that such a σπ carbene character is also prevalent in carbodiphosphorane, C(PH). This bonding situation has been hitherto unexplored in "Carbone" chemistry.