Magnetic order in a metal thiocyanate perovskite analogue

Metal thiocyanate perovskite analogues are a growing class of materials, but although they contain paramagnetic cations there have been no reports of their magnetic properties. Due to the large separations between the paramagnetic cations, with a shortest through-bond distance of 15.1Å, we would expect these materials to be good examples of paramagnets. In this communication we investigate the magnetic properties of a metal thiocyanate framework Cr[Bi(SCN)6]·xH2O. We find that Cr[Bi(SCN)6]·xH2O under- goes long-range magnetic order at TN = 4.0(2) K. We use neutron powder diffraction to determine that Cr[Bi(SCN)6]·xH2O has a MnO type {111}cubic-ordering as its ground state, consistent with frustrated nearest- and next-nearest-neighbour antiferromagnetic interactions. This suggests that appropriate design of metal thiocyanate perovskite analogue structures may reveal a rich vein of frustrated magnetism.