Y23Sr17[Si38O18N67]O9 – An Oxonitridosilicate Oxide with a Unique Layered Structure

Abstract

The oxonitridosilicate oxide Y23Sr17[Si38O18N67]O9 was synthesized in a radiofrequency furnace at 1450 °C starting from YF3, Y2O3, SrH2 and silicon diimide. The driving force of the metathesis reaction is probably the simultaneous formation of SrF2 and H2. The crystal structure was solved and refined from single‐crystal X‐ray diffraction data in space group P63/m (no. 176) with a = 16.5764(4), c = 18.6177(5) Å, and Z = 2 (R1 = 0.0196, wR2 = 0.0377). The results are supported by Rietveld refinement on X‐ray powder data, X‐ray spectroscopy, and IR spectroscopy. The crystal structure contains [Si38O18N67]85– layers built up of vertex‐sharing SiN4 and SiON3 tetrahedra. Lattice energy (MAPLE) and charge distribution (CHARDI) calculations indicate anion and cation ordering, with the exception of one mixed occupied Y/Sr site. UV/Vis spectroscopy and DFT calculations yield an optical optical bandgap of 3.8 eV and an electronic bandgap of 3.6 eV, respectively.