Pressure-Stabilized Cubic Perovskite Oxyhydride BaScO2H

We report a scandium oxyhydride BaScO2H prepared by solid state reaction under high pressure. Rietveld refinements against powder synchrotron X-ray and neutron diffraction data revealed that BaScO2H adopts the ideal cubic perovskite structure (Pm3̅m), where oxide (O2–) and hydride (H–) anions are disordered. 1H nuclear magnetic resonance (NMR) spectroscopy provides a positive chemical shift of about +4.4 ppm, which can be understood by the distance to the nearest (and possibly the next nearest) cation from the H nucleus. A further analysis of the NMR data and calculations based on ab initiorandom structure searches suggest a partial cispreference in ScO4H2octahedra. The present oxyhydride, if compositionally or structurally tuned, may become a candidate for H–conductors.