Materials Data on Sm(MnAl2)4 by Materials Project

Abstract

Sm(MnAl2)4 crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. Sm is bonded in a 4-coordinate geometry to eight equivalent Mn and twelve Al atoms. All Sm–Mn bond lengths are 3.39 Å. There are four shorter (3.00 Å) and eight longer (3.28 Å) Sm–Al bond lengths. Mn is bonded to two equivalent Sm, two equivalent Mn, and eight Al atoms to form distorted MnSm2Mn2Al8 cuboctahedra that share corners with eight equivalent AlSm2Mn4Al6 cuboctahedra, corners with ten equivalent MnSm2Mn2Al8 cuboctahedra, edges with four equivalent MnSm2Mn2Al8 cuboctahedra, edges with four equivalent AlSm2Mn4Al6 cuboctahedra, faces with six equivalent MnSm2Mn2Al8 cuboctahedra, and faces with eight equivalent AlSm2Mn4Al6 cuboctahedra. Both Mn–Mn bond lengths are 2.59 Å. There are four shorter (2.57 Å) and four longer (2.68 Å) Mn–Al bond lengths. There are two inequivalent Al sites. In the first Al site, Al is bonded in a 10-coordinate geometry to one Sm, four equivalent Mn, and five Al atoms. There are a spread of Al–Al bond distances ranging from 2.77–2.85 Å. In the second Al site, Al is bonded to two equivalent Sm, four equivalent Mn, and six Al atoms to form distorted AlSm2Mn4Al6 cuboctahedra that share corners with eight equivalent MnSm2Mn2Al8 cuboctahedra, corners with ten equivalent AlSm2Mn4Al6 cuboctahedra, edges with three equivalent AlSm2Mn4Al6 cuboctahedra, edges with four equivalent MnSm2Mn2Al8 cuboctahedra, faces with seven equivalent AlSm2Mn4Al6 cuboctahedra, and faces with eight equivalent MnSm2Mn2Al8 cuboctahedra. Both Al–Al bond lengths are 2.84 Å.