Mg(BeAs)2 crystallizes in the trigonal P-3m1 space group. Mg(1) is bonded to six equivalent As(1) atoms to form MgAs6 octahedra that share corners with twelve equivalent Be(1)As4 tetrahedra, edges with six equivalent Mg(1)As6 octahedra, and edges with six equivalent Be(1)As4 tetrahedra. Be(1) is bonded to four equivalent As(1) atoms to form BeAs4 tetrahedra that share corners with six equivalent Mg(1)As6 octahedra, corners with six equivalent Be(1)As4 tetrahedra, edges with three equivalent Mg(1)As6 octahedra, and edges with three equivalent Be(1)As4 tetrahedra. The corner-sharing octahedral tilt angles range from 20-52°. As(1) is bonded to three equivalent Mg(1) and four equivalent Be(1) atoms to form a mixture of distorted corner and edge-sharing AsMg3Be4 pentagonal bipyramids.
Mg(BeAs)2 crystallizes in the trigonal P-3m1 space group. Mg(1) is bonded to six equivalent As(1) atoms to form MgAs6 octahedra that share corners with twelve equivalent Be(1)As4 tetrahedra, edges with six equivalent Mg(1)As6 octahedra, and edges with six equivalent Be(1)As4 tetrahedra. All Mg(1)-As(1) bond lengths are 2.76 Å. Be(1) is bonded to four equivalent As(1) atoms to form BeAs4 tetrahedra that share corners with six equivalent Mg(1)As6 octahedra, corners with six equivalent Be(1)As4 tetrahedra, edges with three equivalent Mg(1)As6 octahedra, and edges with three equivalent Be(1)As4 tetrahedra. The corner-sharing octahedral tilt angles range from 20-52°. There are three shorter (2.30 Å) and one longer (2.32 Å) Be(1)-As(1) bond length. As(1) is bonded to three equivalent Mg(1) and four equivalent Be(1) atoms to form a mixture of distorted corner and edge-sharing AsMg3Be4 pentagonal bipyramids.