DOE OSTI2020
Mg2Ga crystallizes in the monoclinic Cm space group. The structure is three-dimensional. there are four inequivalent Mg sites. In the first Mg site, Mg is bonded to seven Mg and three Ga atoms to form distorted MgMg7Ga3 cuboctahedra that share corners with fourteen MgMg7Ga3 cuboctahedra, an edgeedge with one MgMg7Ga5 cuboctahedra, and faces with ten MgMg7Ga3 cuboctahedra. There are a spread of Mg–Mg bond distances ranging from 3.07–3.17 Å. There are two shorter (2.98 Å) and one longer (3.03 Å) Mg–Ga bond lengths. In the second Mg site, Mg is bonded to seven Mg and five Ga atoms to form a mixture of distorted face, edge, and corner-sharing MgMg7Ga5 cuboctahedra. There are a spread of Mg–Mg bond distances ranging from 3.07–3.13 Å. There are a spread of Mg–Ga bond distances ranging from 2.95–3.13 Å. In the third Mg site, Mg is bonded in a 12-coordinate geometry to eight Mg and four Ga atoms. There are two shorter (3.10 Å) and two longer (3.12 Å) Mg–Mg bond lengths. There are a spread of Mg–Ga bond distances ranging from 2.87–3.14 Å. In the fourth Mg site, Mg is bonded to eight Mg and four Ga atoms to form distorted MgMg8Ga4 cuboctahedra that share corners with eight MgMg7Ga3 cuboctahedra, edges with four equivalent MgMg7Ga5 cuboctahedra, and faces with eleven MgMg7Ga3 cuboctahedra. Both Mg–Mg bond lengths are 3.10 Å. There are two shorter (3.05 Å) and two longer (3.14 Å) Mg–Ga bond lengths. There are two inequivalent Ga sites. In the first Ga site, Ga is bonded in a 8-coordinate geometry to eight Mg atoms. In the second Ga site, Ga is bonded in a 8-coordinate geometry to eight Mg atoms.