CaCuGe2O6 is Esseneite structured and crystallizes in the monoclinic C2/c space group. Ca(1) is bonded in a 8-coordinate geometry to two equivalent O(2), two equivalent O(3), and four equivalent O(1) atoms. Cu(1) is bonded to two equivalent O(2) and four equivalent O(3) atoms to form CuO6 octahedra that share corners with six equivalent Ge(1)O4 tetrahedra and edges with two equivalent Cu(1)O6 octahedra. Ge(1) is bonded to one O(2), one O(3), and two equivalent O(1) atoms to form GeO4 tetrahedra that share corners with three equivalent Cu(1)O6 octahedra and corners with two equivalent Ge(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 45-61°. There are three inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to two equivalent Ca(1) and two equivalent Ge(1) atoms. In the second O site, O(2) is bonded in a distorted T-shaped geometry to one Ca(1), one Cu(1), and one Ge(1) atom. In the third O site, O(3) is bonded to one Ca(1), two equivalent Cu(1), and one Ge(1) atom to form a mixture of distorted corner and edge-sharing OCaCu2Ge tetrahedra.
CaCuGe2O6 is Esseneite structured and crystallizes in the monoclinic C2/c space group. Ca(1) is bonded in a 8-coordinate geometry to two equivalent O(2), two equivalent O(3), and four equivalent O(1) atoms. Both Ca(1)-O(2) bond lengths are 2.35 Å. Both Ca(1)-O(3) bond lengths are 2.41 Å. There are two shorter (2.68 Å) and two longer (2.75 Å) Ca(1)-O(1) bond lengths. Cu(1) is bonded to two equivalent O(2) and four equivalent O(3) atoms to form CuO6 octahedra that share corners with six equivalent Ge(1)O4 tetrahedra and edges with two equivalent Cu(1)O6 octahedra. Both Cu(1)-O(2) bond lengths are 2.12 Å. There are two shorter (1.99 Å) and two longer (2.29 Å) Cu(1)-O(3) bond lengths. Ge(1) is bonded to one O(2), one O(3), and two equivalent O(1) atoms to form GeO4 tetrahedra that share corners with three equivalent Cu(1)O6 octahedra and corners with two equivalent Ge(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 45-61°. The Ge(1)-O(2) bond length is 1.74 Å. The Ge(1)-O(3) bond length is 1.76 Å. There is one shorter (1.81 Å) and one longer (1.84 Å) Ge(1)-O(1) bond length. There are three inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to two equivalent Ca(1) and two equivalent Ge(1) atoms. In the second O site, O(2) is bonded in a distorted T-shaped geometry to one Ca(1), one Cu(1), and one Ge(1) atom. In the third O site, O(3) is bonded to one Ca(1), two equivalent Cu(1), and one Ge(1) atom to form a mixture of distorted corner and edge-sharing OCaCu2Ge tetrahedra.