Myriad planar hexacoordinate carbon molecules inviting synthesis

The prototypal hexacoordinate carbon (phC) molecule, CB62- (D-6h), can be annulated by inserting arenes, olefins, or other one or two atom bridging groups into a perimeter B-B bond. Two single-atom units also can bridge opposite CB6 edges. These strategies allow the design of limitless phC derivatives based on CB6 as a building block unit. Illustrative examples, shown to be viable computationally, offer possibilities for experimental realization. These phC's involve multicenter deltahedral sigma bonding, common for boron but unusual for carbon, in the ring planes, as well as pi delocalization.