We propose to conduct XMCD studies (Os L2,3-edge, P and Cl K-edge) on an S = ½ radical, [LnOs=NPCl], to determine local magnetic moments and spin-delocalization across its atoms. Despite consisting of just three atoms, the [NPCl] motif is unprecedented in any inorganic compound. An exact physical quantification of where its unpaired electron density resides (not resorting to calculations) is essential to unravel its chemical reactivity.