Na3SO4H - the first representative of the material class of sulphate hydrides.

The first representative of a novel class of mixed-anionic compounds, the sulfate hydride Na3 SO4 H, and the corresponding deuteride Na3 SO4 D were obtained from the solid-state reaction of NaH or NaD with dry Na2 SO4 . Precise reaction control is required, because too harsh conditions lead to the reduction of sulfate to sulfide. A combined X-ray and neutron diffraction study revealed that the compound crystallizes in the tetragonal space group P4/nmm with the lattice parameters a=7.0034(2) A and c=4.8569(2) A. The sole presence of hydride and absence of hydroxide ions is proven by vibrational spectroscopy and comparison with spectra predicted from quantum chemical calculations. 1 H and 23 Na MAS NMR spectra are consistent with the structure of Na3 SO4 H: a single 1 H peak at 2.9 ppm is observed, while two peaks at 15.0 and 6.2 ppm for the inequivalent 23 Na sites are observed. Elemental analysis and quantum chemical calculations further support these results.