The interplay of spin frustration and quantum fluctuations can lead to the emergence of new and unconventional ground states. The spin-1/2 square-lattice is an ideal testing ground for studies of phenomena such as valence bond solids and spin liquids. Although many theoretical models have examined this problem, experimental realisations of such systems are rather rare. In this proposal we aim to examine AMoOPO4Cl which are possible candidates for a frustrated square-lattice system. Using the D1B diffractometer we aim to determine the ground-state magnetic structure and study its temperature dependence. Please note this study is linked with spectroscopic investigation of this material proposed for IN4 in #73770.