Materials Data on Ca4Mg3H14 by Materials Project

Abstract

Ca4Mg3H14 crystallizes in the hexagonal P-62m space group. The structure is three-dimensional. there are two inequivalent Ca2+ sites. In the first Ca2+ site, Ca2+ is bonded in a 9-coordinate geometry to nine H1- atoms. There are a spread of Ca–H bond distances ranging from 2.30–2.43 Å. In the second Ca2+ site, Ca2+ is bonded in a 9-coordinate geometry to nine H1- atoms. There are three shorter (2.33 Å) and six longer (2.47 Å) Ca–H bond lengths. Mg2+ is bonded in a 5-coordinate geometry to seven H1- atoms. There are a spread of Mg–H bond distances ranging from 1.83–2.41 Å. There are four inequivalent H1- sites. In the first H1- site, H1- is bonded to three Ca2+ and one Mg2+ atom to form distorted HCa3Mg tetrahedra that share corners with fourteen HCa4 tetrahedra, corners with two equivalent HCa2Mg3 trigonal bipyramids, edges with four HCa4 tetrahedra, and edges with two equivalent HCa2Mg3 trigonal bipyramids. In the second H1- site, H1- is bonded to four Ca2+ atoms to form HCa4 tetrahedra that share corners with ten HCa4 tetrahedra, corners with six equivalent HCa2Mg3 trigonal bipyramids, and edges with eight HCa4 tetrahedra. In the third H1- site, H1- is bonded to two equivalent Ca2+ and three equivalent Mg2+ atoms to form distorted HCa2Mg3 trigonal bipyramids that share corners with ten HCa4 tetrahedra, corners with four equivalent HCa2Mg3 trigonal bipyramids, edges with four equivalent HCa3Mg tetrahedra, and faces with two equivalent HCa2Mg3 trigonal bipyramids. In the fourth H1- site, H1- is bonded in a trigonal planar geometry to three equivalent Mg2+ atoms.