Pressure-induced structural and magnetic ordering transitions in the J1–J2 square lattice antiferromagnets AMoOPO4Cl (A = K, Rb)

A hypothetical P 4/ n phase, involving the mutual twisting of MoO 5 Cl and PO 4 polyhedra, has been constructed and considered suitable for the high-pressure phase of AMoOPO 4 Cl (A = K, Rb) as it effectively replicates the experimental observations.