Heteroanionic materials offer a rich chemical space for developing new materials with targeted properties. To understand and control the properties of heteroanionic materials requires a detailed characterisation of their structures-in particular, the specific arrangement of the component anions. Resolving the anionic substructure of anion-disordered oxyfluorides is particularly challenging, because X-ray and neutron Bragg scattering experiments give only an average structural description. Resolving local structural details in anion-disordered oxyfluorides, therefore, requires using alternative complementary experimental or computational techniques.