Structures and relative energies of (a) 1 T_d-MoS₂ and (b) T ′ ′ -MoS₂, respectively.^[59,163] (c) Atomic structures of monolayer metal oxides, including ZrO₂, HfO₂, NiO₂, PtO₂, GeO₂, SnO₂, MoO₂, WO₂, SnO₂, MoO₃, TiO₂, Mo₂O₅ and W₂O₅.^[80] Reprinted with permission from Ref. [59], Copyright 2016 Royal Society of Chemistry. Ref. [163], Copyright 2018 Royal Society of Chemistry. Ref. [80], Copyright 2019 Royal Society of Chemistry.