Materials Data on SmMg5 by Materials Project
SmMg5 crystallizes in the monoclinic Cm space group. The structure is three-dimensional. there are five inequivalent Mg sites. In the first Mg site, Mg is bonded in a 12-coordinate geometry to nine Mg and two equivalent Sm atoms. There are a spread of Mg–Mg bond distances ranging from 3.16–3.32 Å. Both Mg–Sm bond lengths are 3.35 Å. In the second Mg site, Mg is bonded to ten Mg and two equivalent Sm atoms to form distorted MgSm2Mg10 cuboctahedra that share corners with four equivalent MgSm2Mg10 cuboctahedra, corners with four equivalent SmSm2Mg10 cuboctahedra, edges with six equivalent MgSm2Mg10 cuboctahedra, edges with six equivalent SmSm2Mg10 cuboctahedra, faces with two equivalent SmSm2Mg10 cuboctahedra, and faces with eleven MgSm2Mg10 cuboctahedra. There are a spread of Mg–Mg bond distances ranging from 3.15–3.48 Å. Both Mg–Sm bond lengths are 3.33 Å. In the third Mg site, Mg is bonded to ten Mg and two equivalent Sm atoms to form MgSm2Mg10 cuboctahedra that share corners with eight MgSm2Mg10 cuboctahedra, edges with twelve MgSm2Mg10 cuboctahedra, faces with six equivalent SmSm2Mg10 cuboctahedra, and faces with seven MgSm2Mg10 cuboctahedra. There are four shorter (3.25 Å) and two longer (3.33 Å) Mg–Mg bond lengths. Both Mg–Sm bond lengths are 3.39 Å. In the fourth Mg site, Mg is bonded in a 12-coordinate geometry to nine Mg and two equivalent Sm atoms. There are two shorter (3.17 Å) and two longer (3.25 Å) Mg–Mg bond lengths. Both Mg–Sm bond lengths are 3.33 Å. In the fifth Mg site, Mg is bonded to ten Mg and two equivalent Sm atoms to form distorted MgSm2Mg10 cuboctahedra that share corners with eight MgSm2Mg10 cuboctahedra, edges with six equivalent MgSm2Mg10 cuboctahedra, edges with six equivalent SmSm2Mg10 cuboctahedra, faces with three equivalent SmSm2Mg10 cuboctahedra, and faces with ten MgSm2Mg10 cuboctahedra. Both Mg–Mg bond lengths are 3.25 Å. Both Mg–Sm bond lengths are 3.35 Å. Sm is bonded to ten Mg and two equivalent Sm atoms to form SmSm2Mg10 cuboctahedra that share corners with four equivalent MgSm2Mg10 cuboctahedra, corners with four equivalent SmSm2Mg10 cuboctahedra, edges with twelve MgSm2Mg10 cuboctahedra, faces with two equivalent SmSm2Mg10 cuboctahedra, and faces with eleven MgSm2Mg10 cuboctahedra. Both Sm–Sm bond lengths are 3.25 Å.