Materials Data on MgAl3 by Materials Project

Abstract

Al3Mg is beta Cu3Ti-like structured and crystallizes in the hexagonal P6_3/mmc space group. The structure is three-dimensional. Mg is bonded to twelve Al atoms to form MgAl12 cuboctahedra that share corners with six equivalent MgAl12 cuboctahedra, corners with twelve AlMg4Al8 cuboctahedra, edges with eighteen AlMg4Al8 cuboctahedra, faces with eight equivalent MgAl12 cuboctahedra, and faces with twelve AlMg4Al8 cuboctahedra. There are six shorter (2.91 Å) and six longer (2.99 Å) Mg–Al bond lengths. There are three inequivalent Al sites. In the first Al site, Al is bonded to four equivalent Mg and eight Al atoms to form distorted AlMg4Al8 cuboctahedra that share corners with four equivalent MgAl12 cuboctahedra, corners with fourteen AlMg4Al8 cuboctahedra, edges with six equivalent MgAl12 cuboctahedra, edges with twelve AlMg4Al8 cuboctahedra, faces with four equivalent MgAl12 cuboctahedra, and faces with sixteen AlMg4Al8 cuboctahedra. There are a spread of Al–Al bond distances ranging from 2.83–2.99 Å. In the second Al site, Al is bonded to four equivalent Mg and eight Al atoms to form distorted AlMg4Al8 cuboctahedra that share corners with four equivalent MgAl12 cuboctahedra, corners with fourteen AlMg4Al8 cuboctahedra, edges with six equivalent MgAl12 cuboctahedra, edges with twelve AlMg4Al8 cuboctahedra, faces with four equivalent MgAl12 cuboctahedra, and faces with sixteen AlMg4Al8 cuboctahedra. Both Al–Al bond lengths are 2.94 Å. In the third Al site, Al is bonded to four equivalent Mg and eight Al atoms to form distorted AlMg4Al8 cuboctahedra that share corners with four equivalent MgAl12 cuboctahedra, corners with fourteen AlMg4Al8 cuboctahedra, edges with six equivalent MgAl12 cuboctahedra, edges with twelve AlMg4Al8 cuboctahedra, faces with four equivalent MgAl12 cuboctahedra, and faces with sixteen AlMg4Al8 cuboctahedra. There are one shorter (2.83 Å) and one longer (2.99 Å) Al–Al bond lengths.