Materials Data on Ba6Mg7H26 by Materials Project

Abstract

Ba6Mg7H26 crystallizes in the orthorhombic Immm space group. The structure is three-dimensional. there are two inequivalent Ba2+ sites. In the first Ba2+ site, Ba2+ is bonded in a 12-coordinate geometry to twelve H1- atoms. There are a spread of Ba–H bond distances ranging from 2.64–3.16 Å. In the second Ba2+ site, Ba2+ is bonded to twelve H1- atoms to form distorted BaH12 cuboctahedra that share corners with two equivalent BaH12 cuboctahedra, a faceface with one BaH12 cuboctahedra, and faces with six MgH6 octahedra. There are a spread of Ba–H bond distances ranging from 2.64–2.94 Å. There are four inequivalent Mg2+ sites. In the first Mg2+ site, Mg2+ is bonded to six H1- atoms to form distorted MgH6 octahedra that share corners with three MgH6 octahedra and faces with two equivalent BaH12 cuboctahedra. The corner-sharing octahedra tilt angles range from 0–49°. There are a spread of Mg–H bond distances ranging from 1.95–2.28 Å. In the second Mg2+ site, Mg2+ is bonded to six H1- atoms to form MgH6 octahedra that share corners with four MgH6 octahedra and faces with two equivalent BaH12 cuboctahedra. The corner-sharing octahedra tilt angles range from 3–55°. There are a spread of Mg–H bond distances ranging from 1.92–2.11 Å. In the third Mg2+ site, Mg2+ is bonded to six H1- atoms to form a mixture of edge and corner-sharing MgH6 octahedra. The corner-sharing octahedra tilt angles range from 49–55°. There are a spread of Mg–H bond distances ranging from 1.95–1.97 Å. In the fourth Mg2+ site, Mg2+ is bonded to six H1- atoms to form MgH6 octahedra that share corners with six MgH6 octahedra and faces with four equivalent BaH12 cuboctahedra. The corner-sharing octahedra tilt angles range from 0–3°. There is two shorter (1.94 Å) and four longer (2.00 Å) Mg–H bond length. There are seven inequivalent H1- sites. In the first H1- site, H1- is bonded in a distorted linear geometry to four Ba2+ and two Mg2+ atoms. In the second H1- site, H1- is bonded in a distorted bent 120 degrees geometry to two equivalent Ba2+ and two Mg2+ atoms. In the third H1- site, H1- is bonded in a distorted single-bond geometry to three Ba2+ and one Mg2+ atom. In the fourth H1- site, H1- is bonded in an L-shaped geometry to two equivalent Ba2+ and two equivalent Mg2+ atoms. In the fifth H1- site, H1- is bonded in a distorted trigonal planar geometry to three Mg2+ atoms. In the sixth H1- site, H1- is bonded in a 1-coordinate geometry to four Ba2+ and two Mg2+ atoms. In the seventh H1- site, H1- is bonded to three Ba2+ and one Mg2+ atom to form a mixture of distorted edge and corner-sharing HBa3Mg tetrahedra.