Er3Co4Ge13 crystallizes in the cubic Pm-3n space group. Er(1) is bonded in a 16-coordinate geometry to four equivalent Co(1) and twelve equivalent Ge(2) atoms. Co(1) is bonded in a 9-coordinate geometry to three equivalent Er(1) and six equivalent Ge(2) atoms. There are two inequivalent Ge sites. In the first Ge site, Ge(2) is bonded in a 9-coordinate geometry to three equivalent Er(1), two equivalent Co(1), one Ge(1), and three equivalent Ge(2) atoms. In the second Ge site, Ge(1) is bonded in a cuboctahedral geometry to twelve equivalent Ge(2) atoms.
Er3Co4Ge13 crystallizes in the cubic Pm-3n space group. Er(1) is bonded in a 16-coordinate geometry to four equivalent Co(1) and twelve equivalent Ge(2) atoms. All Er(1)-Co(1) bond lengths are 3.10 Å. There are four shorter (3.08 Å) and eight longer (3.09 Å) Er(1)-Ge(2) bond lengths. Co(1) is bonded in a 9-coordinate geometry to three equivalent Er(1) and six equivalent Ge(2) atoms. All Co(1)-Ge(2) bond lengths are 2.40 Å. There are two inequivalent Ge sites. In the first Ge site, Ge(2) is bonded in a 9-coordinate geometry to three equivalent Er(1), two equivalent Co(1), one Ge(1), and three equivalent Ge(2) atoms. The Ge(2)-Ge(1) bond length is 2.99 Å. There is one shorter (2.68 Å) and two longer (2.96 Å) Ge(2)-Ge(2) bond lengths. In the second Ge site, Ge(1) is bonded in a cuboctahedral geometry to twelve equivalent Ge(2) atoms.