Materials Data on Mg(BeAs)2 by Materials Project
Mg(BeAs)2 crystallizes in the trigonal P-3m1 space group. The structure is three-dimensional. Mg2+ is bonded to six equivalent As3- atoms to form MgAs6 octahedra that share corners with twelve equivalent BeAs4 tetrahedra, edges with six equivalent MgAs6 octahedra, and edges with six equivalent BeAs4 tetrahedra. All Mg–As bond lengths are 2.78 Å. Be2+ is bonded to four equivalent As3- atoms to form BeAs4 tetrahedra that share corners with six equivalent MgAs6 octahedra, corners with six equivalent BeAs4 tetrahedra, edges with three equivalent MgAs6 octahedra, and edges with three equivalent BeAs4 tetrahedra. The corner-sharing octahedra tilt angles range from 20–52°. There are three shorter (2.31 Å) and one longer (2.33 Å) Be–As bond lengths. As3- is bonded to three equivalent Mg2+ and four equivalent Be2+ atoms to form a mixture of distorted edge and corner-sharing AsMg3Be4 pentagonal bipyramids.