EuMg2H6 crystallizes in the tetragonal P4/mmm space group. Mg(1) is bonded in a 6-coordinate geometry to one H(2), one H(3), and four equivalent H(1) atoms. Eu(1) is bonded to four equivalent H(2) and eight equivalent H(1) atoms to form a mixture of corner and face-sharing EuH12 cuboctahedra. There are three inequivalent H sites. In the first H site, H(1) is bonded in a 4-coordinate geometry to two equivalent Mg(1) and two equivalent Eu(1) atoms. In the second H site, H(2) is bonded to two equivalent Mg(1) and four equivalent Eu(1) atoms to form a mixture of corner and edge-sharing HEu4Mg2 octahedra. The corner-sharing octahedra are not tilted. In the third H site, H(3) is bonded in a linear geometry to two equivalent Mg(1) atoms.
EuMg2H6 crystallizes in the tetragonal P4/mmm space group. Mg(1) is bonded in a 6-coordinate geometry to one H(2), one H(3), and four equivalent H(1) atoms. The Mg(1)-H(2) bond length is 2.18 Å. The Mg(1)-H(3) bond length is 1.80 Å. All Mg(1)-H(1) bond lengths are 1.94 Å. Eu(1) is bonded to four equivalent H(2) and eight equivalent H(1) atoms to form a mixture of corner and face-sharing EuH12 cuboctahedra. All Eu(1)-H(2) bond lengths are 2.64 Å. All Eu(1)-H(1) bond lengths are 2.49 Å. There are three inequivalent H sites. In the first H site, H(1) is bonded in a 4-coordinate geometry to two equivalent Mg(1) and two equivalent Eu(1) atoms. In the second H site, H(2) is bonded to two equivalent Mg(1) and four equivalent Eu(1) atoms to form a mixture of corner and edge-sharing HEu4Mg2 octahedra. The corner-sharing octahedra are not tilted. In the third H site, H(3) is bonded in a linear geometry to two equivalent Mg(1) atoms.