An Unprecedented Fully H^–-Substituted Phosphate Hydride Sr₅(PO₄)₃H Expanding the Apatite Family

The apatite family is a mineral class that also contains the biologically very important hydroxyapatite. Here, we are reporting on the synthesis and characterization of a fully hydride-substituted strontium apatite, which could be obtained via mechanochemical synthesis and subsequent annealing treatment. The full substitution by hydride anions is proven by various methods, such as neutron powder diffraction of a deuterated sample Sr₅(PO₄)₃D, as well ¹H MAS solid state NMR combined with quantum chemical calculations, vibrational spectroscopy and elemental analysis. The present work expands the apatite family from the known halide and hydroxide apatites to the fully hydride-anion-substituted variant and is expected to open up a new field of materials containing coexistent phosphate and hydride anions.