Figure 2. Total energies per atom of possible phosphorene allotropes (red five-point stars mean phosphorene allotropes predicted previously, black ones mean those discovered in our present work, red-solid circles represent Hittorfene¹⁷, black phosphorene bilayers, black phosphorus (3D) and phosphorus nanotube arrays PNT(θ,τ)¹⁹ considered in for comparison) are summarized here in different categories.

The total energy of α-P is set to be zero as reference. From these results, we can see that G1 is energetically more stable than most of all the previously proposed 2D phosphorene allotropes.