Materials Data on LaMg2H7 by Materials Project
LaMg2H7 crystallizes in the tetragonal P4_12_12 space group. The structure is three-dimensional. Mg2+ is bonded to seven H1- atoms to form distorted MgH7 pentagonal bipyramids that share corners with two equivalent LaH12 cuboctahedra, corners with two equivalent MgH7 pentagonal bipyramids, edges with four equivalent LaH12 cuboctahedra, and edges with four equivalent MgH7 pentagonal bipyramids. There are a spread of Mg–H bond distances ranging from 1.92–2.12 Å. La3+ is bonded to twelve H1- atoms to form distorted LaH12 cuboctahedra that share corners with four equivalent MgH7 pentagonal bipyramids, edges with eight equivalent MgH7 pentagonal bipyramids, and faces with four equivalent LaH12 cuboctahedra. There are a spread of La–H bond distances ranging from 2.38–2.53 Å. There are four inequivalent H1- sites. In the first H1- site, H1- is bonded to four equivalent Mg2+ atoms to form a mixture of edge and corner-sharing HMg4 tetrahedra. In the second H1- site, H1- is bonded in a 1-coordinate geometry to one Mg2+ and two equivalent La3+ atoms. In the third H1- site, H1- is bonded to two equivalent Mg2+ and two equivalent La3+ atoms to form a mixture of edge and corner-sharing HLa2Mg2 tetrahedra. In the fourth H1- site, H1- is bonded in a 4-coordinate geometry to two equivalent Mg2+ and two equivalent La3+ atoms.