MgErAg crystallizes in the hexagonal P-62m space group. Mg(1) is bonded to two equivalent Ag(1) and two equivalent Ag(2) atoms to form a mixture of distorted corner and edge-sharing MgAg4 tetrahedra. Er(1) is bonded in a 5-coordinate geometry to one Ag(2) and four equivalent Ag(1) atoms. There are two inequivalent Ag sites. In the first Ag site, Ag(2) is bonded in a 9-coordinate geometry to six equivalent Mg(1) and three equivalent Er(1) atoms. In the second Ag site, Ag(1) is bonded in a 9-coordinate geometry to three equivalent Mg(1) and six equivalent Er(1) atoms.
MgErAg crystallizes in the hexagonal P-62m space group. Mg(1) is bonded to two equivalent Ag(1) and two equivalent Ag(2) atoms to form a mixture of distorted corner and edge-sharing MgAg4 tetrahedra. Both Mg(1)-Ag(1) bond lengths are 2.90 Å. Both Mg(1)-Ag(2) bond lengths are 2.78 Å. Er(1) is bonded in a 5-coordinate geometry to one Ag(2) and four equivalent Ag(1) atoms. The Er(1)-Ag(2) bond length is 3.10 Å. All Er(1)-Ag(1) bond lengths are 3.08 Å. There are two inequivalent Ag sites. In the first Ag site, Ag(2) is bonded in a 9-coordinate geometry to six equivalent Mg(1) and three equivalent Er(1) atoms. In the second Ag site, Ag(1) is bonded in a 9-coordinate geometry to three equivalent Mg(1) and six equivalent Er(1) atoms.