This experiment seeks to resolve an ambiguity surrounding the structure of a prototypical relaxor ferroelectric Pb(Mg1/3Nb2/3)O3 (PMN). Relaxors have been studied extensively for nearly 60 years. Despite all the efforts, the nanoscale structure of these materials remains elusive. In particular, for PMN, several distinct models have been proposed (e.g., polar nanoregions vs glass-like dipole network) and the debate is ongoing. We intend to address this problem by exploiting recent advances in structural refinements using multiple types of data. Local atomic displacements and their correlations will be determined using simultaneous fitting of the neutron total-scattering and X-ray single-crystal diffuse-scattering data in the RMCProfile software. The goal of the proposed measurements is to provide the neutron total-scattering data for this study.