Materials Data on BaMg2FeH8 by Materials Project
BaMg2FeH8 crystallizes in the trigonal P-3m1 space group. The structure is three-dimensional. Ba2+ is bonded to twelve H1- atoms to form BaH12 cuboctahedra that share edges with six equivalent BaH12 cuboctahedra and faces with two equivalent FeH6 octahedra. There are six shorter (2.74 Å) and six longer (2.83 Å) Ba–H bond lengths. Mg2+ is bonded in a 1-coordinate geometry to ten H1- atoms. There are a spread of Mg–H bond distances ranging from 1.94–2.29 Å. Fe2+ is bonded to six equivalent H1- atoms to form FeH6 octahedra that share faces with two equivalent BaH12 cuboctahedra. All Fe–H bond lengths are 1.58 Å. There are two inequivalent H1- sites. In the first H1- site, H1- is bonded in a 1-coordinate geometry to one Ba2+, three equivalent Mg2+, and one Fe2+ atom. In the second H1- site, H1- is bonded to three equivalent Ba2+ and one Mg2+ atom to form a mixture of distorted edge and corner-sharing HBa3Mg tetrahedra.