Er2Mn(GeO3)4 crystallizes in the orthorhombic Cmme space group. There are two inequivalent Er sites. In the first Er site, Er(1) is bonded to two equivalent O(4) and four equivalent O(2) atoms to form ErO6 octahedra that share corners with eight equivalent Ge(1)O4 tetrahedra. In the second Er site, Er(2) is bonded in a 8-coordinate geometry to four equivalent O(1) and four equivalent O(2) atoms. Mn(1) is bonded to two equivalent O(3) and four equivalent O(1) atoms to form MnO6 octahedra that share corners with eight equivalent Ge(1)O4 tetrahedra. Ge(1) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form GeO4 tetrahedra that share corners with two equivalent Er(1)O6 octahedra, corners with two equivalent Mn(1)O6 octahedra, and corners with two equivalent Ge(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 50-70°. There are four inequivalent O sites. In the first O site, O(3) is bonded in a trigonal non-coplanar geometry to one Mn(1) and two equivalent Ge(1) atoms. In the second O site, O(4) is bonded in a trigonal non-coplanar geometry to one Er(1) and two equivalent Ge(1) atoms. In the third O site, O(1) is bonded in a distorted trigonal planar geometry to one Er(2), one Mn(1), and one Ge(1) atom. In the fourth O site, O(2) is bonded in a distorted trigonal planar geometry to one Er(1), one Er(2), and one Ge(1) atom.
Er2Mn(GeO3)4 crystallizes in the orthorhombic Cmme space group. There are two inequivalent Er sites. In the first Er site, Er(1) is bonded to two equivalent O(4) and four equivalent O(2) atoms to form ErO6 octahedra that share corners with eight equivalent Ge(1)O4 tetrahedra. Both Er(1)-O(4) bond lengths are 2.43 Å. All Er(1)-O(2) bond lengths are 2.19 Å. In the second Er site, Er(2) is bonded in a 8-coordinate geometry to four equivalent O(1) and four equivalent O(2) atoms. All Er(2)-O(1) bond lengths are 2.34 Å. All Er(2)-O(2) bond lengths are 2.38 Å. Mn(1) is bonded to two equivalent O(3) and four equivalent O(1) atoms to form MnO6 octahedra that share corners with eight equivalent Ge(1)O4 tetrahedra. Both Mn(1)-O(3) bond lengths are 2.48 Å. All Mn(1)-O(1) bond lengths are 2.16 Å. Ge(1) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form GeO4 tetrahedra that share corners with two equivalent Er(1)O6 octahedra, corners with two equivalent Mn(1)O6 octahedra, and corners with two equivalent Ge(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 50-70°. The Ge(1)-O(1) bond length is 1.74 Å. The Ge(1)-O(2) bond length is 1.75 Å. The Ge(1)-O(3) bond length is 1.81 Å. The Ge(1)-O(4) bond length is 1.85 Å. There are four inequivalent O sites. In the first O site, O(3) is bonded in a trigonal non-coplanar geometry to one Mn(1) and two equivalent Ge(1) atoms. In the second O site, O(4) is bonded in a trigonal non-coplanar geometry to one Er(1) and two equivalent Ge(1) atoms. In the third O site, O(1) is bonded in a distorted trigonal planar geometry to one Er(2), one Mn(1), and one Ge(1) atom. In the fourth O site, O(2) is bonded in a distorted trigonal planar geometry to one Er(1), one Er(2), and one Ge(1) atom.