The title compound and its deuteride were synthesized by hydrogenating/deuterating SrAl2 at 50 bar H2/D2 pressure and temperatures below 200°C. As found by in situ X-ray powder diffraction, the hydrogenation of SrAl2 proceeds in three steps, with SrAl2H2 as the first product. SrAl2H2 and SrAl2D2 were characterized by X-ray and neutron powder diffraction. They crystallize with a new trigonal structure in space group P3̄m1 (164), cell parameters: a=4.5283(1) angstrom, c=4.7215(2) angstrom (hydride), a=4.5253(1) angstrom, c=4.7214(2) angstrom (deuteride), Z=1. The main feature of this structure is a two-dimensional polymer Zintl anion, ∞2[AIH-]2n, in which one H atom is covalently bonded to each Al atom. SrAl2H2 is the first example of a Zintl phase hydride, i.e., the first Zintl phase in which hydrogen atoms are a part of the Zintl anion.
All Science Journal Classification (ASJC) codes
- Mechanics of Materials
- Mechanical Engineering
- Metals and Alloys
- Materials Chemistry