Er5Ge4 crystallizes in the orthorhombic Pnma space group. There are three inequivalent Er sites. In the first Er site, Er(1) is bonded in a 6-coordinate geometry to one Ge(3), two equivalent Ge(2), and three equivalent Ge(1) atoms. In the second Er site, Er(2) is bonded in a 7-coordinate geometry to one Ge(2), two equivalent Ge(3), and four equivalent Ge(1) atoms. In the third Er site, Er(3) is bonded to two equivalent Ge(1), two equivalent Ge(2), and two equivalent Ge(3) atoms to form corner-sharing ErGe6 octahedra. The corner-sharing octahedral tilt angles range from 51-53°. There are three inequivalent Ge sites. In the first Ge site, Ge(3) is bonded in a 9-coordinate geometry to two equivalent Er(1), two equivalent Er(3), four equivalent Er(2), and one Ge(2) atom. In the second Ge site, Ge(1) is bonded in a 8-coordinate geometry to one Er(3), three equivalent Er(1), and four equivalent Er(2) atoms. In the third Ge site, Ge(2) is bonded in a 9-coordinate geometry to two equivalent Er(2), two equivalent Er(3), four equivalent Er(1), and one Ge(3) atom.
Er5Ge4 crystallizes in the orthorhombic Pnma space group. There are three inequivalent Er sites. In the first Er site, Er(1) is bonded in a 6-coordinate geometry to one Ge(3), two equivalent Ge(2), and three equivalent Ge(1) atoms. The Er(1)-Ge(3) bond length is 2.98 Å. There is one shorter (2.93 Å) and one longer (2.94 Å) Er(1)-Ge(2) bond length. There are a spread of Er(1)-Ge(1) bond distances ranging from 2.80-2.93 Å. In the second Er site, Er(2) is bonded in a 7-coordinate geometry to one Ge(2), two equivalent Ge(3), and four equivalent Ge(1) atoms. The Er(2)-Ge(2) bond length is 3.13 Å. There is one shorter (2.94 Å) and one longer (3.15 Å) Er(2)-Ge(3) bond length. There are a spread of Er(2)-Ge(1) bond distances ranging from 2.92-3.45 Å. In the third Er site, Er(3) is bonded to two equivalent Ge(1), two equivalent Ge(2), and two equivalent Ge(3) atoms to form corner-sharing ErGe6 octahedra. The corner-sharing octahedral tilt angles range from 51-53°. Both Er(3)-Ge(1) bond lengths are 2.98 Å. There is one shorter (2.88 Å) and one longer (3.05 Å) Er(3)-Ge(2) bond length. There is one shorter (2.89 Å) and one longer (3.02 Å) Er(3)-Ge(3) bond length. There are three inequivalent Ge sites. In the first Ge site, Ge(3) is bonded in a 9-coordinate geometry to two equivalent Er(1), two equivalent Er(3), four equivalent Er(2), and one Ge(2) atom. The Ge(3)-Ge(2) bond length is 2.71 Å. In the second Ge site, Ge(1) is bonded in a 8-coordinate geometry to one Er(3), three equivalent Er(1), and four equivalent Er(2) atoms. In the third Ge site, Ge(2) is bonded in a 9-coordinate geometry to two equivalent Er(2), two equivalent Er(3), four equivalent Er(1), and one Ge(3) atom.