Easy-plane anisotropy and Heisenberg superexchange cannot produce spin canting in this model, would instead select a unique spin direction: the intersection between the two staggered easy-planes. In these structures, the selected direction would correspond (assuming the easy-planes are oriented normal to the N-M-N axes) to spins oriented along the MCl 2 chain normal to the plane of the organic ligand. Indeed, the spins do largely lie on this direction for both FeCl 2 (pym) and FeCl 2 (btd). The deviation of the moment direction from this axis must arise from DMI interactions, rhombic anisotropy or higher order interactions neglected in this analysis.