Materials Data on Sr2Mg3H10 by Materials Project

Abstract

Sr2Mg3H10 crystallizes in the monoclinic C2/m space group. The structure is three-dimensional. there are two inequivalent Sr2+ sites. In the first Sr2+ site, Sr2+ is bonded in a 12-coordinate geometry to twelve H1- atoms. There are a spread of Sr–H bond distances ranging from 2.48–2.94 Å. In the second Sr2+ site, Sr2+ is bonded to twelve H1- atoms to form distorted SrH12 cuboctahedra that share corners with four equivalent SrH12 cuboctahedra, corners with two equivalent MgH6 octahedra, an edgeedge with one SrH12 cuboctahedra, edges with two equivalent MgH6 octahedra, and faces with five MgH6 octahedra. The corner-sharing octahedral tilt angles are 47°. There are a spread of Sr–H bond distances ranging from 2.55–2.89 Å. There are three inequivalent Mg2+ sites. In the first Mg2+ site, Mg2+ is bonded to six H1- atoms to form MgH6 octahedra that share corners with two equivalent SrH12 cuboctahedra, corners with three MgH6 octahedra, an edgeedge with one MgH6 octahedra, and faces with two equivalent SrH12 cuboctahedra. The corner-sharing octahedra tilt angles range from 9–51°. There are a spread of Mg–H bond distances ranging from 1.89–2.08 Å. In the second Mg2+ site, Mg2+ is bonded to six H1- atoms to form MgH6 octahedra that share corners with five MgH6 octahedra and faces with three equivalent SrH12 cuboctahedra. The corner-sharing octahedra tilt angles range from 0–58°. There are a spread of Mg–H bond distances ranging from 1.90–1.99 Å. In the third Mg2+ site, Mg2+ is bonded to six H1- atoms to form MgH6 octahedra that share corners with four MgH6 octahedra, edges with two equivalent SrH12 cuboctahedra, and edges with two equivalent MgH6 octahedra. The corner-sharing octahedra tilt angles range from 51–58°. All Mg–H bond lengths are 1.92 Å. There are eight inequivalent H1- sites. In the first H1- site, H1- is bonded in a distorted single-bond geometry to four Sr2+ and one Mg2+ atom. In the second H1- site, H1- is bonded in a distorted L-shaped geometry to one Sr2+ and two equivalent Mg2+ atoms. In the third H1- site, H1- is bonded in a 4-coordinate geometry to two equivalent Sr2+ and two equivalent Mg2+ atoms. In the fourth H1- site, H1- is bonded in a linear geometry to four Sr2+ and two equivalent Mg2+ atoms. In the fifth H1- site, H1- is bonded to two Sr2+ and two Mg2+ atoms to form a mixture of distorted edge and corner-sharing HSr2Mg2 tetrahedra. In the sixth H1- site, H1- is bonded to three Sr2+ and one Mg2+ atom to form distorted HSr3Mg tetrahedra that share corners with eight HSr2Mg2 tetrahedra and edges with three equivalent HSr3Mg tetrahedra. In the seventh H1- site, H1- is bonded in a trigonal planar geometry to three Mg2+ atoms. In the eighth H1- site, H1- is bonded in a 2-coordinate geometry to three Sr2+ and two Mg2+ atoms.