Mg5Pr4Ge6 crystallizes in the orthorhombic Cmc2_1 space group. There are five inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to one Ge(2), one Ge(3), and two equivalent Ge(6) atoms to form distorted MgGe4 tetrahedra that share corners with three equivalent Pr(3)Ge6 octahedra, corners with three equivalent Pr(4)Ge6 octahedra, corners with two equivalent Mg(1)Ge4 tetrahedra, corners with two equivalent Mg(4)Ge4 tetrahedra,  an edgeedge with one Mg(2)Ge4 tetrahedra, edges with two equivalent Mg(3)Ge4 tetrahedra, and edges with two equivalent Mg(5)Ge4 tetrahedra. The corner-sharing octahedral tilt angles range from 55-60°. In the second Mg site, Mg(2) is bonded to one Ge(2), one Ge(3), and two equivalent Ge(1) atoms to form distorted MgGe4 tetrahedra that share  a cornercorner with one Pr(3)Ge6 octahedra,  a cornercorner with one Pr(4)Ge6 octahedra, corners with two equivalent Mg(2)Ge4 tetrahedra, corners with two equivalent Mg(3)Ge4 tetrahedra, corners with two equivalent Mg(4)Ge4 tetrahedra, corners with two equivalent Mg(5)Ge4 tetrahedra, edges with two equivalent Pr(3)Ge6 octahedra, edges with two equivalent Pr(4)Ge6 octahedra,  an edgeedge with one Mg(1)Ge4 tetrahedra, and  an edgeedge with one Mg(4)Ge4 tetrahedra. The corner-sharing octahedral tilt angles range from 9-11°. In the third Mg site, Mg(3) is bonded to one Ge(4), one Ge(6), and two equivalent Ge(3) atoms to form distorted MgGe4 tetrahedra that share corners with two equivalent Pr(3)Ge6 octahedra,  a cornercorner with one Mg(4)Ge4 tetrahedra,  a cornercorner with one Mg(5)Ge4 tetrahedra, corners with two equivalent Mg(2)Ge4 tetrahedra, corners with two equivalent Mg(3)Ge4 tetrahedra,  an edgeedge with one Pr(3)Ge6 octahedra, edges with two equivalent Pr(4)Ge6 octahedra, and edges with two equivalent Mg(1)Ge4 tetrahedra. The corner-sharing octahedral tilt angles are 15°. In the fourth Mg site, Mg(4) is bonded to one Ge(5), one Ge(6), and two equivalent Ge(1) atoms to form distorted MgGe4 tetrahedra that share corners with two equivalent Pr(4)Ge6 octahedra,  a cornercorner with one Mg(3)Ge4 tetrahedra, corners with two equivalent Mg(1)Ge4 tetrahedra, corners with two equivalent Mg(2)Ge4 tetrahedra, corners with two equivalent Mg(4)Ge4 tetrahedra, corners with two equivalent Mg(5)Ge4 tetrahedra, edges with two equivalent Pr(3)Ge6 octahedra, and  an edgeedge with one Mg(2)Ge4 tetrahedra. The corner-sharing octahedral tilt angles are 63°. In the fifth Mg site, Mg(5) is bonded to one Ge(5), one Ge(6), and two equivalent Ge(2) atoms to form MgGe4 tetrahedra that share corners with two equivalent Pr(4)Ge6 octahedra,  a cornercorner with one Mg(3)Ge4 tetrahedra, corners with two equivalent Mg(2)Ge4 tetrahedra, corners with two equivalent Mg(4)Ge4 tetrahedra, corners with two equivalent Mg(5)Ge4 tetrahedra,  an edgeedge with one Pr(4)Ge6 octahedra, edges with two equivalent Pr(3)Ge6 octahedra, and edges with two equivalent Mg(1)Ge4 tetrahedra. The corner-sharing octahedral tilt angles are 13°. There are four inequivalent Pr sites. In the first Pr site, Pr(1) is bonded in a 7-coordinate geometry to one Ge(1), two equivalent Ge(4), two equivalent Ge(5), and two equivalent Ge(6) atoms. In the second Pr site, Pr(2) is bonded in a 6-coordinate geometry to two equivalent Ge(4), two equivalent Ge(5), and two equivalent Ge(6) atoms. In the third Pr site, Pr(3) is bonded to one Ge(1), one Ge(2), two equivalent Ge(3), and two equivalent Ge(5) atoms to form PrGe6 octahedra that share  a cornercorner with one Pr(4)Ge6 octahedra,  a cornercorner with one Mg(2)Ge4 tetrahedra, corners with two equivalent Mg(3)Ge4 tetrahedra, corners with three equivalent Mg(1)Ge4 tetrahedra, edges with two equivalent Pr(3)Ge6 octahedra, edges with two equivalent Pr(4)Ge6 octahedra,  an edgeedge with one Mg(3)Ge4 tetrahedra, edges with two equivalent Mg(2)Ge4 tetrahedra, edges with two equivalent Mg(4)Ge4 tetrahedra, and edges with two equivalent Mg(5)Ge4 tetrahedra. The corner-sharing octahedral tilt angles are 43°. In the fourth Pr site, Pr(4) is bonded to one Ge(1), one Ge(3), two equivalent Ge(2), and two equivalent Ge(4) atoms to form PrGe6 octahedra that share  a cornercorner with one Pr(3)Ge6 octahedra,  a cornercorner with one Mg(2)Ge4 tetrahedra, corners with two equivalent Mg(4)Ge4 tetrahedra, corners with two equivalent Mg(5)Ge4 tetrahedra, corners with three equivalent Mg(1)Ge4 tetrahedra, edges with two equivalent Pr(3)Ge6 octahedra, edges with two equivalent Pr(4)Ge6 octahedra,  an edgeedge with one Mg(5)Ge4 tetrahedra, edges with two equivalent Mg(2)Ge4 tetrahedra, and edges with two equivalent Mg(3)Ge4 tetrahedra. The corner-sharing octahedral tilt angles are 43°. There are six inequivalent Ge sites. In the first Ge site, Ge(1) is bonded in a 7-coordinate geometry to two equivalent Mg(2), two equivalent Mg(4), one Pr(1), one Pr(3), and one Pr(4) atom. In the second Ge site, Ge(2) is bonded to one Mg(1), one Mg(2), two equivalent Mg(5), one Pr(3), and two equivalent Pr(4) atoms to form distorted edge-sharing GePr3Mg4 pentagonal bipyramids. In the third Ge site, Ge(3) is bonded to one Mg(1), one Mg(2), two equivalent Mg(3), one Pr(4), and two equivalent Pr(3) atoms to form distorted edge-sharing GePr3Mg4 pentagonal bipyramids. In the fourth Ge site, Ge(4) is bonded in a 8-coordinate geometry to one Mg(3), two equivalent Pr(1), two equivalent Pr(2), two equivalent Pr(4), and one Ge(5) atom. In the fifth Ge site, Ge(5) is bonded in a 9-coordinate geometry to one Mg(4), one Mg(5), two equivalent Pr(1), two equivalent Pr(2), two equivalent Pr(3), and one Ge(4) atom. In the sixth Ge site, Ge(6) is bonded in a 9-coordinate geometry to one Mg(3), one Mg(4), one Mg(5), two equivalent Mg(1), two equivalent Pr(1), and two equivalent Pr(2) atoms.
Mg5Pr4Ge6 crystallizes in the orthorhombic Cmc2_1 space group. There are five inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to one Ge(2), one Ge(3), and two equivalent Ge(6) atoms to form distorted MgGe4 tetrahedra that share corners with three equivalent Pr(3)Ge6 octahedra, corners with three equivalent Pr(4)Ge6 octahedra, corners with two equivalent Mg(1)Ge4 tetrahedra, corners with two equivalent Mg(4)Ge4 tetrahedra,  an edgeedge with one Mg(2)Ge4 tetrahedra, edges with two equivalent Mg(3)Ge4 tetrahedra, and edges with two equivalent Mg(5)Ge4 tetrahedra. The corner-sharing octahedral tilt angles range from 55-60°. The Mg(1)-Ge(2) bond length is 2.73 Å. The Mg(1)-Ge(3) bond length is 2.77 Å. Both Mg(1)-Ge(6) bond lengths are 2.79 Å. In the second Mg site, Mg(2) is bonded to one Ge(2), one Ge(3), and two equivalent Ge(1) atoms to form distorted MgGe4 tetrahedra that share  a cornercorner with one Pr(3)Ge6 octahedra,  a cornercorner with one Pr(4)Ge6 octahedra, corners with two equivalent Mg(2)Ge4 tetrahedra, corners with two equivalent Mg(3)Ge4 tetrahedra, corners with two equivalent Mg(4)Ge4 tetrahedra, corners with two equivalent Mg(5)Ge4 tetrahedra, edges with two equivalent Pr(3)Ge6 octahedra, edges with two equivalent Pr(4)Ge6 octahedra,  an edgeedge with one Mg(1)Ge4 tetrahedra, and  an edgeedge with one Mg(4)Ge4 tetrahedra. The corner-sharing octahedral tilt angles range from 9-11°. The Mg(2)-Ge(2) bond length is 2.75 Å. The Mg(2)-Ge(3) bond length is 2.74 Å. Both Mg(2)-Ge(1) bond lengths are 2.80 Å. In the third Mg site, Mg(3) is bonded to one Ge(4), one Ge(6), and two equivalent Ge(3) atoms to form distorted MgGe4 tetrahedra that share corners with two equivalent Pr(3)Ge6 octahedra,  a cornercorner with one Mg(4)Ge4 tetrahedra,  a cornercorner with one Mg(5)Ge4 tetrahedra, corners with two equivalent Mg(2)Ge4 tetrahedra, corners with two equivalent Mg(3)Ge4 tetrahedra,  an edgeedge with one Pr(3)Ge6 octahedra, edges with two equivalent Pr(4)Ge6 octahedra, and edges with two equivalent Mg(1)Ge4 tetrahedra. The corner-sharing octahedral tilt angles are 15°. The Mg(3)-Ge(4) bond length is 2.86 Å. The Mg(3)-Ge(6) bond length is 2.87 Å. Both Mg(3)-Ge(3) bond lengths are 2.67 Å. In the fourth Mg site, Mg(4) is bonded to one Ge(5), one Ge(6), and two equivalent Ge(1) atoms to form distorted MgGe4 tetrahedra that share corners with two equivalent Pr(4)Ge6 octahedra,  a cornercorner with one Mg(3)Ge4 tetrahedra, corners with two equivalent Mg(1)Ge4 tetrahedra, corners with two equivalent Mg(2)Ge4 tetrahedra, corners with two equivalent Mg(4)Ge4 tetrahedra, corners with two equivalent Mg(5)Ge4 tetrahedra, edges with two equivalent Pr(3)Ge6 octahedra, and  an edgeedge with one Mg(2)Ge4 tetrahedra. The corner-sharing octahedral tilt angles are 63°. The Mg(4)-Ge(5) bond length is 2.92 Å. The Mg(4)-Ge(6) bond length is 2.71 Å. Both Mg(4)-Ge(1) bond lengths are 2.63 Å. In the fifth Mg site, Mg(5) is bonded to one Ge(5), one Ge(6), and two equivalent Ge(2) atoms to form MgGe4 tetrahedra that share corners with two equivalent Pr(4)Ge6 octahedra,  a cornercorner with one Mg(3)Ge4 tetrahedra, corners with two equivalent Mg(2)Ge4 tetrahedra, corners with two equivalent Mg(4)Ge4 tetrahedra, corners with two equivalent Mg(5)Ge4 tetrahedra,  an edgeedge with one Pr(4)Ge6 octahedra, edges with two equivalent Pr(3)Ge6 octahedra, and edges with two equivalent Mg(1)Ge4 tetrahedra. The corner-sharing octahedral tilt angles are 13°. The Mg(5)-Ge(5) bond length is 2.81 Å. The Mg(5)-Ge(6) bond length is 2.85 Å. Both Mg(5)-Ge(2) bond lengths are 2.71 Å. There are four inequivalent Pr sites. In the first Pr site, Pr(1) is bonded in a 7-coordinate geometry to one Ge(1), two equivalent Ge(4), two equivalent Ge(5), and two equivalent Ge(6) atoms. The Pr(1)-Ge(1) bond length is 3.18 Å. Both Pr(1)-Ge(4) bond lengths are 3.20 Å. Both Pr(1)-Ge(5) bond lengths are 3.40 Å. Both Pr(1)-Ge(6) bond lengths are 3.24 Å. In the second Pr site, Pr(2) is bonded in a 6-coordinate geometry to two equivalent Ge(4), two equivalent Ge(5), and two equivalent Ge(6) atoms. Both Pr(2)-Ge(4) bond lengths are 3.22 Å. Both Pr(2)-Ge(5) bond lengths are 3.19 Å. Both Pr(2)-Ge(6) bond lengths are 3.24 Å. In the third Pr site, Pr(3) is bonded to one Ge(1), one Ge(2), two equivalent Ge(3), and two equivalent Ge(5) atoms to form PrGe6 octahedra that share  a cornercorner with one Pr(4)Ge6 octahedra,  a cornercorner with one Mg(2)Ge4 tetrahedra, corners with two equivalent Mg(3)Ge4 tetrahedra, corners with three equivalent Mg(1)Ge4 tetrahedra, edges with two equivalent Pr(3)Ge6 octahedra, edges with two equivalent Pr(4)Ge6 octahedra,  an edgeedge with one Mg(3)Ge4 tetrahedra, edges with two equivalent Mg(2)Ge4 tetrahedra, edges with two equivalent Mg(4)Ge4 tetrahedra, and edges with two equivalent Mg(5)Ge4 tetrahedra. The corner-sharing octahedral tilt angles are 43°. The Pr(3)-Ge(1) bond length is 3.12 Å. The Pr(3)-Ge(2) bond length is 3.09 Å. Both Pr(3)-Ge(3) bond lengths are 3.12 Å. Both Pr(3)-Ge(5) bond lengths are 3.24 Å. In the fourth Pr site, Pr(4) is bonded to one Ge(1), one Ge(3), two equivalent Ge(2), and two equivalent Ge(4) atoms to form PrGe6 octahedra that share  a cornercorner with one Pr(3)Ge6 octahedra,  a cornercorner with one Mg(2)Ge4 tetrahedra, corners with two equivalent Mg(4)Ge4 tetrahedra, corners with two equivalent Mg(5)Ge4 tetrahedra, corners with three equivalent Mg(1)Ge4 tetrahedra, edges with two equivalent Pr(3)Ge6 octahedra, edges with two equivalent Pr(4)Ge6 octahedra,  an edgeedge with one Mg(5)Ge4 tetrahedra, edges with two equivalent Mg(2)Ge4 tetrahedra, and edges with two equivalent Mg(3)Ge4 tetrahedra. The corner-sharing octahedral tilt angles are 43°. The Pr(4)-Ge(1) bond length is 3.09 Å. The Pr(4)-Ge(3) bond length is 3.08 Å. Both Pr(4)-Ge(2) bond lengths are 3.06 Å. Both Pr(4)-Ge(4) bond lengths are 3.19 Å. There are six inequivalent Ge sites. In the first Ge site, Ge(1) is bonded in a 7-coordinate geometry to two equivalent Mg(2), two equivalent Mg(4), one Pr(1), one Pr(3), and one Pr(4) atom. In the second Ge site, Ge(2) is bonded to one Mg(1), one Mg(2), two equivalent Mg(5), one Pr(3), and two equivalent Pr(4) atoms to form distorted edge-sharing GePr3Mg4 pentagonal bipyramids. In the third Ge site, Ge(3) is bonded to one Mg(1), one Mg(2), two equivalent Mg(3), one Pr(4), and two equivalent Pr(3) atoms to form distorted edge-sharing GePr3Mg4 pentagonal bipyramids. In the fourth Ge site, Ge(4) is bonded in a 8-coordinate geometry to one Mg(3), two equivalent Pr(1), two equivalent Pr(2), two equivalent Pr(4), and one Ge(5) atom. The Ge(4)-Ge(5) bond length is 2.60 Å. In the fifth Ge site, Ge(5) is bonded in a 9-coordinate geometry to one Mg(4), one Mg(5), two equivalent Pr(1), two equivalent Pr(2), two equivalent Pr(3), and one Ge(4) atom. In the sixth Ge site, Ge(6) is bonded in a 9-coordinate geometry to one Mg(3), one Mg(4), one Mg(5), two equivalent Mg(1), two equivalent Pr(1), and two equivalent Pr(2) atoms.