Materials Data on SmMg5Sb4 by Materials Project
Mg5SmSb4 crystallizes in the trigonal P-3m1 space group. The structure is three-dimensional. there are three inequivalent Mg2+ sites. In the first Mg2+ site, Mg2+ is bonded to four Sb3- atoms to form MgSb4 tetrahedra that share corners with three equivalent MgSb6 octahedra, corners with three equivalent SmSb6 octahedra, corners with six equivalent MgSb4 tetrahedra, edges with three equivalent MgSb6 octahedra, and edges with three equivalent MgSb4 tetrahedra. The corner-sharing octahedra tilt angles range from 12–56°. There are three shorter (2.84 Å) and one longer (2.98 Å) Mg–Sb bond lengths. In the second Mg2+ site, Mg2+ is bonded to six equivalent Sb3- atoms to form MgSb6 octahedra that share corners with twelve MgSb4 tetrahedra, edges with six equivalent MgSb6 octahedra, and edges with six equivalent MgSb4 tetrahedra. All Mg–Sb bond lengths are 3.14 Å. In the third Mg2+ site, Mg2+ is bonded to four Sb3- atoms to form MgSb4 tetrahedra that share corners with three equivalent MgSb6 octahedra, corners with three equivalent SmSb6 octahedra, corners with six equivalent MgSb4 tetrahedra, edges with three equivalent SmSb6 octahedra, and edges with three equivalent MgSb4 tetrahedra. The corner-sharing octahedra tilt angles range from 14–59°. There are three shorter (2.87 Å) and one longer (2.90 Å) Mg–Sb bond lengths. Sm2+ is bonded to six equivalent Sb3- atoms to form SmSb6 octahedra that share corners with twelve MgSb4 tetrahedra, edges with six equivalent SmSb6 octahedra, and edges with six equivalent MgSb4 tetrahedra. All Sm–Sb bond lengths are 3.25 Å. There are two inequivalent Sb3- sites. In the first Sb3- site, Sb3- is bonded to four Mg2+ and three equivalent Sm2+ atoms to form a mixture of distorted edge and corner-sharing SbSm3Mg4 pentagonal bipyramids. In the second Sb3- site, Sb3- is bonded in a 7-coordinate geometry to seven Mg2+ atoms.