SCXD refinement allowed us to tentatively locate the positions of the H atoms and demonstrate that the orientation of the NH + 4 cation in 1 is ordered. Single crystal neutron diffraction (SCND) measurements on a large single crystal (16 mm ) at 20 K, carried out using instrument D19 at the ILL, allowed accurate determination of the H atom positions and its anisotropic atomic displacement parameters, which were consistent with those observed via SCXD. Variable temperature unit cell measurements between 20 K and 260 K and an additional full collection at 260 K found no evidence of any structural phase transitions in this range. Refinement of the 260 K dataset confirmed the presence of NH + 4 orientational order throughout this temperature range. The ordering of the NH + 4 cation does not lower the symmetry of 1 beyond the symmetry of compound 2.