Materials Data on EuMg2H5 by Materials Project
Mg2EuH5 crystallizes in the tetragonal P4/nmm space group. The structure is two-dimensional and consists of one Mg2EuH5 sheet oriented in the (0, 0, 1) direction. there are two inequivalent Mg sites. In the first Mg site, Mg is bonded in a 5-coordinate geometry to five H atoms. There are four shorter (1.94 Å) and one longer (2.27 Å) Mg–H bond lengths. In the second Mg site, Mg is bonded in a 5-coordinate geometry to five H atoms. There are four shorter (1.95 Å) and one longer (2.27 Å) Mg–H bond lengths. Eu is bonded to twelve H atoms to form a mixture of corner and face-sharing EuH12 cuboctahedra. There are eight shorter (2.48 Å) and four longer (2.61 Å) Eu–H bond lengths. There are two inequivalent H sites. In the first H site, H is bonded to two Mg and four equivalent Eu atoms to form HEu4Mg2 octahedra that share corners with four equivalent HEu4Mg2 octahedra, corners with sixteen equivalent HEu2Mg2 trigonal pyramids, edges with four equivalent HEu4Mg2 octahedra, and faces with eight equivalent HEu2Mg2 trigonal pyramids. The corner-sharing octahedral tilt angles are 0°. In the second H site, H is bonded to two Mg and two equivalent Eu atoms to form distorted HEu2Mg2 trigonal pyramids that share corners with four equivalent HEu4Mg2 octahedra, corners with ten equivalent HEu2Mg2 trigonal pyramids, edges with five equivalent HEu2Mg2 trigonal pyramids, and faces with two equivalent HEu4Mg2 octahedra. The corner-sharing octahedral tilt angles are 58°.