Mg2As crystallizes in the orthorhombic Immm space group. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to four equivalent As(1) atoms to form a mixture of distorted corner and edge-sharing MgAs4 trigonal pyramids. In the second Mg site, Mg(2) is bonded in a 4-coordinate geometry to four equivalent As(1) atoms. As(1) is bonded in a 8-coordinate geometry to four equivalent Mg(1) and four equivalent Mg(2) atoms.
Mg2As crystallizes in the orthorhombic Immm space group. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to four equivalent As(1) atoms to form a mixture of distorted corner and edge-sharing MgAs4 trigonal pyramids. There are two shorter (2.69 Å) and two longer (2.88 Å) Mg(1)-As(1) bond lengths. In the second Mg site, Mg(2) is bonded in a 4-coordinate geometry to four equivalent As(1) atoms. All Mg(2)-As(1) bond lengths are 2.92 Å. As(1) is bonded in a 8-coordinate geometry to four equivalent Mg(1) and four equivalent Mg(2) atoms.