An overview of the common synthesis routes is given in SI Section 6 together with their calculated Gibbs free energy of reaction (∆G reac ). Rettenwander and coworkers showed that LiCl is still present after following the synthesis outlined in equation 6 suggesting that Li 3 OCl is Cl-poor. This indicates that OH -is likely present in the samples due to an excess of LiOH. Nevertheless, a calculated stability region can be formed and is given in Figure . What is seen is a very narrow region (straight line) between Li-rich/anion-poor (µ Li = -2.17 eV, µ O = 0 eV, µ Cl = -2.97 eV) designated point A, and Li-poor/anion-rich ((µ Li = 0 eV, µ O = -4. 35