While experimental techniques that probe long-range correlations between atoms, such as X-ray or neutron Bragg scattering, can determine the average crystal structure of anion-disordered materials, these methods cannot resolve any short-range ordering, if present. Instead, these methods yield only an effective unit cell where each anion site is occupied by a statistical average of the constituent anion species. Short-range structural information can be obtained from scattering experiments in the form of pair-distribution function (PDF) data . However, for heteroanionic materials containing anions with similar X-ray or neutron scattering factors, such as oxyfluorides, it is often not possible to assign anion site occupations based solely on PDF data, and alternative methods must be used to resolve the anionic structure of these materials.