ErRh2Ge crystallizes in the hexagonal P6_3/mmc space group. There are two inequivalent Er sites. In the first Er site, Er(1) is bonded in a 9-coordinate geometry to one Er(2), nine equivalent Rh(1), and three equivalent Ge(3) atoms. In the second Er site, Er(2) is bonded in a 20-coordinate geometry to two equivalent Er(1), twelve equivalent Rh(1), three equivalent Ge(1), and three equivalent Ge(2) atoms. Rh(1) is bonded in a 12-coordinate geometry to two equivalent Er(2), three equivalent Er(1), four equivalent Rh(1), one Ge(1), one Ge(2), and one Ge(3) atom. There are three inequivalent Ge sites. In the first Ge site, Ge(1) is bonded in a 9-coordinate geometry to three equivalent Er(2) and six equivalent Rh(1) atoms. In the second Ge site, Ge(2) is bonded in a 9-coordinate geometry to three equivalent Er(2) and six equivalent Rh(1) atoms. In the third Ge site, Ge(3) is bonded to six equivalent Er(1) and six equivalent Rh(1) atoms to form distorted edge-sharing GeEr6Rh6 cuboctahedra.
ErRh2Ge crystallizes in the hexagonal P6_3/mmc space group. There are two inequivalent Er sites. In the first Er site, Er(1) is bonded in a 9-coordinate geometry to one Er(2), nine equivalent Rh(1), and three equivalent Ge(3) atoms. The Er(1)-Er(2) bond length is 3.26 Å. There are three shorter (3.00 Å) and six longer (3.08 Å) Er(1)-Rh(1) bond lengths. All Er(1)-Ge(3) bond lengths are 3.24 Å. In the second Er site, Er(2) is bonded in a 20-coordinate geometry to two equivalent Er(1), twelve equivalent Rh(1), three equivalent Ge(1), and three equivalent Ge(2) atoms. All Er(2)-Rh(1) bond lengths are 3.34 Å. All Er(2)-Ge(1) bond lengths are 3.18 Å. All Er(2)-Ge(2) bond lengths are 3.18 Å. Rh(1) is bonded in a 12-coordinate geometry to two equivalent Er(2), three equivalent Er(1), four equivalent Rh(1), one Ge(1), one Ge(2), and one Ge(3) atom. There are two shorter (2.74 Å) and two longer (2.78 Å) Rh(1)-Rh(1) bond lengths. The Rh(1)-Ge(1) bond length is 2.48 Å. The Rh(1)-Ge(2) bond length is 2.46 Å. The Rh(1)-Ge(3) bond length is 2.53 Å. There are three inequivalent Ge sites. In the first Ge site, Ge(1) is bonded in a 9-coordinate geometry to three equivalent Er(2) and six equivalent Rh(1) atoms. In the second Ge site, Ge(2) is bonded in a 9-coordinate geometry to three equivalent Er(2) and six equivalent Rh(1) atoms. In the third Ge site, Ge(3) is bonded to six equivalent Er(1) and six equivalent Rh(1) atoms to form distorted edge-sharing GeEr6Rh6 cuboctahedra.