Co3Al2GeO8 is Spinel-derived structured and crystallizes in the orthorhombic Imm2 space group. There are two inequivalent Co sites. In the first Co site, Co(1) is bonded to two equivalent O(3) and two equivalent O(4) atoms to form CoO4 tetrahedra that share corners with six equivalent Co(2)O6 octahedra and corners with six equivalent Al(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 51-61°. In the second Co site, Co(2) is bonded to one O(1), one O(3), two equivalent O(2), and two equivalent O(4) atoms to form CoO6 octahedra that share corners with three equivalent Co(1)O4 tetrahedra, corners with three equivalent Ge(1)O4 tetrahedra, edges with two equivalent Co(2)O6 octahedra, and edges with four equivalent Al(1)O6 octahedra. Al(1) is bonded to one O(2), one O(4), two equivalent O(1), and two equivalent O(3) atoms to form AlO6 octahedra that share corners with three equivalent Co(1)O4 tetrahedra, corners with three equivalent Ge(1)O4 tetrahedra, edges with two equivalent Al(1)O6 octahedra, and edges with four equivalent Co(2)O6 octahedra. Ge(1) is bonded to two equivalent O(1) and two equivalent O(2) atoms to form GeO4 tetrahedra that share corners with six equivalent Co(2)O6 octahedra and corners with six equivalent Al(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 55-58°. There are four inequivalent O sites. In the first O site, O(1) is bonded in a rectangular see-saw-like geometry to one Co(2), two equivalent Al(1), and one Ge(1) atom. In the second O site, O(2) is bonded in a rectangular see-saw-like geometry to two equivalent Co(2), one Al(1), and one Ge(1) atom. In the third O site, O(3) is bonded in a rectangular see-saw-like geometry to one Co(1), one Co(2), and two equivalent Al(1) atoms. In the fourth O site, O(4) is bonded in a rectangular see-saw-like geometry to one Co(1), two equivalent Co(2), and one Al(1) atom.
Co3Al2GeO8 is Spinel-derived structured and crystallizes in the orthorhombic Imm2 space group. There are two inequivalent Co sites. In the first Co site, Co(1) is bonded to two equivalent O(3) and two equivalent O(4) atoms to form CoO4 tetrahedra that share corners with six equivalent Co(2)O6 octahedra and corners with six equivalent Al(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 51-61°. Both Co(1)-O(3) bond lengths are 1.96 Å. Both Co(1)-O(4) bond lengths are 1.95 Å. In the second Co site, Co(2) is bonded to one O(1), one O(3), two equivalent O(2), and two equivalent O(4) atoms to form CoO6 octahedra that share corners with three equivalent Co(1)O4 tetrahedra, corners with three equivalent Ge(1)O4 tetrahedra, edges with two equivalent Co(2)O6 octahedra, and edges with four equivalent Al(1)O6 octahedra. The Co(2)-O(1) bond length is 2.17 Å. The Co(2)-O(3) bond length is 2.08 Å. Both Co(2)-O(2) bond lengths are 2.11 Å. Both Co(2)-O(4) bond lengths are 2.02 Å. Al(1) is bonded to one O(2), one O(4), two equivalent O(1), and two equivalent O(3) atoms to form AlO6 octahedra that share corners with three equivalent Co(1)O4 tetrahedra, corners with three equivalent Ge(1)O4 tetrahedra, edges with two equivalent Al(1)O6 octahedra, and edges with four equivalent Co(2)O6 octahedra. The Al(1)-O(2) bond length is 2.01 Å. The Al(1)-O(4) bond length is 1.85 Å. Both Al(1)-O(1) bond lengths are 2.08 Å. Both Al(1)-O(3) bond lengths are 1.89 Å. Ge(1) is bonded to two equivalent O(1) and two equivalent O(2) atoms to form GeO4 tetrahedra that share corners with six equivalent Co(2)O6 octahedra and corners with six equivalent Al(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 55-58°. Both Ge(1)-O(1) bond lengths are 1.87 Å. Both Ge(1)-O(2) bond lengths are 1.83 Å. There are four inequivalent O sites. In the first O site, O(1) is bonded in a rectangular see-saw-like geometry to one Co(2), two equivalent Al(1), and one Ge(1) atom. In the second O site, O(2) is bonded in a rectangular see-saw-like geometry to two equivalent Co(2), one Al(1), and one Ge(1) atom. In the third O site, O(3) is bonded in a rectangular see-saw-like geometry to one Co(1), one Co(2), and two equivalent Al(1) atoms. In the fourth O site, O(4) is bonded in a rectangular see-saw-like geometry to one Co(1), two equivalent Co(2), and one Al(1) atom.