LiSr2SiO4H, an Air-Stable Hydride as Host for Eu(II) Luminescence

Florian Gehlhaar; Raphael Finger; Nicolas Zapp; Marko Bertmer; Holger Kohlmann

doi:10.1021/acs.inorgchem.8b01780

LiSr₂SiO₄H, an Air-Stable Hydride as Host for Eu(II) Luminescence

Inorg Chem. 2018 Oct 1;57(19):11851-11854. doi: 10.1021/acs.inorgchem.8b01780. Epub 2018 Sep 11.

Authors

Florian Gehlhaar¹, Raphael Finger¹, Nicolas Zapp¹, Marko Bertmer², Holger Kohlmann¹

Affiliations

¹ Inorganic Chemistry , Leipzig University , Leipzig 04103 , Germany.
² Felix Bloch Institute for Solid State Physics , Leipzig University , Leipzig 04103 , Germany.

PMID: 30203971
DOI: 10.1021/acs.inorgchem.8b01780

Abstract

LiSr₂SiO₄H is synthesized by solid-state reaction of LiH and α-Sr₂SiO₄. It crystallizes in space group P2₁/ m ( a = 658.63(4) pm, b = 542.36(3) pm, c = 695.01(4) pm, β = 112.5637(9)°) as proven by X-ray and neutron diffraction, is isotypic to LiSr₂SiO₄F, and exhibits isolated SiO₄ tetrahedra. Hydride anions are located in Li₂Sr₄ octahedra, which share faces to form columns, with H-H distances of 271.18(2) pm. NMR, IR, and Raman spectroscopy, density measurements, elemental analysis, and theoretical calculations confirm these results. Despite its hydridic nature, it is stable in air up to 550 K. When doped with europium, it emits bright yellow-green light with an intensity maximum at 560 nm for LiSr_1.98Eu_0.02SiO₄H. Even after treatment in water for several hours, the solid shows luminescence. The broad emission peak is attributed to the allowed 4f⁶5d → 4f⁷ transition of divalent europium. LiSr₂SiO₄H is the first silicate hydride, a class of compounds that might have potential as host for luminescent materials.