Hf5Ge4 crystallizes in the orthorhombic Pnma space group. There are three inequivalent Hf sites. In the first Hf site, Hf(1) is bonded to one Ge(3), two equivalent Ge(2), and four equivalent Ge(1) atoms to form distorted HfGe7 pentagonal bipyramids that share corners with four equivalent Hf(3)Ge6 octahedra, corners with six equivalent Hf(1)Ge7 pentagonal bipyramids, edges with two equivalent Hf(1)Ge7 pentagonal bipyramids, faces with two equivalent Hf(3)Ge6 octahedra, and faces with three equivalent Hf(1)Ge7 pentagonal bipyramids. The corner-sharing octahedral tilt angles range from 46-52°. In the second Hf site, Hf(2) is bonded in a 6-coordinate geometry to one Ge(2), two equivalent Ge(3), and three equivalent Ge(1) atoms. In the third Hf site, Hf(3) is bonded to two equivalent Ge(1), two equivalent Ge(2), and two equivalent Ge(3) atoms to form distorted HfGe6 octahedra that share corners with four equivalent Hf(3)Ge6 octahedra, corners with eight equivalent Hf(1)Ge7 pentagonal bipyramids, and faces with four equivalent Hf(1)Ge7 pentagonal bipyramids. The corner-sharing octahedral tilt angles range from 47-55°. There are three inequivalent Ge sites. In the first Ge site, Ge(3) is bonded in a 9-coordinate geometry to two equivalent Hf(1), two equivalent Hf(3), four equivalent Hf(2), and one Ge(2) atom. In the second Ge site, Ge(1) is bonded in a 8-coordinate geometry to one Hf(3), three equivalent Hf(2), and four equivalent Hf(1) atoms. In the third Ge site, Ge(2) is bonded in a 9-coordinate geometry to two equivalent Hf(2), two equivalent Hf(3), four equivalent Hf(1), and one Ge(3) atom.
Hf5Ge4 crystallizes in the orthorhombic Pnma space group. There are three inequivalent Hf sites. In the first Hf site, Hf(1) is bonded to one Ge(3), two equivalent Ge(2), and four equivalent Ge(1) atoms to form distorted HfGe7 pentagonal bipyramids that share corners with four equivalent Hf(3)Ge6 octahedra, corners with six equivalent Hf(1)Ge7 pentagonal bipyramids, edges with two equivalent Hf(1)Ge7 pentagonal bipyramids, faces with two equivalent Hf(3)Ge6 octahedra, and faces with three equivalent Hf(1)Ge7 pentagonal bipyramids. The corner-sharing octahedral tilt angles range from 46-52°. The Hf(1)-Ge(3) bond length is 2.93 Å. There is one shorter (2.78 Å) and one longer (2.99 Å) Hf(1)-Ge(2) bond length. There are a spread of Hf(1)-Ge(1) bond distances ranging from 2.78-3.12 Å. In the second Hf site, Hf(2) is bonded in a 6-coordinate geometry to one Ge(2), two equivalent Ge(3), and three equivalent Ge(1) atoms. The Hf(2)-Ge(2) bond length is 2.79 Å. There is one shorter (2.70 Å) and one longer (2.73 Å) Hf(2)-Ge(3) bond length. There are a spread of Hf(2)-Ge(1) bond distances ranging from 2.63-2.81 Å. In the third Hf site, Hf(3) is bonded to two equivalent Ge(1), two equivalent Ge(2), and two equivalent Ge(3) atoms to form distorted HfGe6 octahedra that share corners with four equivalent Hf(3)Ge6 octahedra, corners with eight equivalent Hf(1)Ge7 pentagonal bipyramids, and faces with four equivalent Hf(1)Ge7 pentagonal bipyramids. The corner-sharing octahedral tilt angles range from 47-55°. Both Hf(3)-Ge(1) bond lengths are 2.81 Å. There is one shorter (2.68 Å) and one longer (2.73 Å) Hf(3)-Ge(2) bond length. There is one shorter (2.73 Å) and one longer (2.91 Å) Hf(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 Hf(1), two equivalent Hf(3), four equivalent Hf(2), and one Ge(2) atom. The Ge(3)-Ge(2) bond length is 2.62 Å. In the second Ge site, Ge(1) is bonded in a 8-coordinate geometry to one Hf(3), three equivalent Hf(2), and four equivalent Hf(1) atoms. In the third Ge site, Ge(2) is bonded in a 9-coordinate geometry to two equivalent Hf(2), two equivalent Hf(3), four equivalent Hf(1), and one Ge(3) atom.