The bonding between TM and phosphorene is reported to take place by covalent bonding in two different doping schemes: adatom and substitutional doping (see Fig. ). In adatom doped phosphorene, the dopant atom is adsorbed at the surface of phosphorene in atom top, in-plane bridge, and hollow conformations, where the hollow position is the most stable . In substitutionally doped phosphorene, the dopant atom replaces one phosphorous atom, forming stable chemical bonds with unsaturated P atoms . In terms of stability, the adatom doping of phosphorene with TM has proven to achieve higher stable interactions (high magnitude of binding energies) compared to the doping of graphene with 3d TM atoms (which reach binding energies in the range of 0.3-3.4 eV) . TM adatoms also show higher stability on phosphorene compared with non-transition metal atoms such as C, N, O, Li, Na, and Mg, which are bonded to phosphorene with a binding energy of 0.6-5.3 eV . On the other hand, the substitutional doping of phosphorene with stable binding energies, and comparable to those on substitutionally doped graphene with metal and semimetallic atoms, where binding energies of 0.6-9.6 eV are reported . In this way, a wide series of atoms (including metals, alkaline metals, transition metals, metalloids, non-metals, and halogens) can be substitutionally introduced into phosphorene with binding energies of 2.1-9.2 eV .