Unlike the cyanide-based Prussian blue materials, which crystallise with high symmetry cubic structures and often have substantial cation and anion disorder, these thiocyanate frameworks are well-ordered and adopt distorted monoclinic structures. The size of the distortion is demonstrated by greatly reduced volume compared to the hypothetical cubic Fm 3m aristotype, which is 54% for Fe[Bi(SCN) 6 ] [Fig. )]. This distortion means that the structures are much less porous than might be expected from consideration of the length of the NCS -ligand alone.