CaNiGe2O6 crystallizes in the monoclinic P2_1/c space group. Ca(1) is bonded in a 7-coordinate geometry to one O(2), one O(3), one O(4), one O(5), one O(6), and two equivalent O(1) atoms. Ni(1) is bonded to one O(3), one O(4), two equivalent O(5), and two equivalent O(6) atoms to form NiO6 octahedra that share corners with three equivalent Ge(1)O4 tetrahedra, corners with two equivalent Ge(2)O5 trigonal bipyramids, edges with two equivalent Ni(1)O6 octahedra, and  an edgeedge with one Ge(2)O5 trigonal bipyramid. There are two inequivalent Ge sites. In the first Ge site, Ge(1) is bonded to one O(4), one O(5), and two equivalent O(2) atoms to form GeO4 tetrahedra that share corners with three equivalent Ni(1)O6 octahedra and corners with two equivalent Ge(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 45-61°. In the second Ge site, Ge(2) is bonded to one O(6), two equivalent O(1), and two equivalent O(3) atoms to form GeO5 trigonal bipyramids that share corners with two equivalent Ni(1)O6 octahedra, corners with two equivalent Ge(2)O5 trigonal bipyramids,  an edgeedge with one Ni(1)O6 octahedra, and  an edgeedge with one Ge(2)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles range from 41-43°. There are six inequivalent O sites. In the first O site, O(5) is bonded in a distorted rectangular see-saw-like geometry to one Ca(1), two equivalent Ni(1), and one Ge(1) atom. In the second O site, O(6) is bonded to one Ca(1), two equivalent Ni(1), and one Ge(2) atom to form distorted OCaNi2Ge tetrahedra that share corners with two equivalent O(6)CaNi2Ge tetrahedra and corners with four equivalent O(1)Ca2Ge2 tetrahedra. In the third O site, O(1) is bonded to two equivalent Ca(1) and two equivalent Ge(2) atoms to form distorted OCa2Ge2 tetrahedra that share corners with four equivalent O(6)CaNi2Ge tetrahedra and edges with two equivalent O(1)Ca2Ge2 tetrahedra. In the fourth O site, O(2) is bonded in a trigonal planar geometry to one Ca(1) and two equivalent Ge(1) atoms. In the fifth O site, O(3) is bonded in a distorted see-saw-like geometry to one Ca(1), one Ni(1), and two equivalent Ge(2) atoms. In the sixth O site, O(4) is bonded in a distorted trigonal planar geometry to one Ca(1), one Ni(1), and one Ge(1) atom.
CaNiGe2O6 crystallizes in the monoclinic P2_1/c space group. Ca(1) is bonded in a 7-coordinate geometry to one O(2), one O(3), one O(4), one O(5), one O(6), and two equivalent O(1) atoms. The Ca(1)-O(2) bond length is 2.46 Å. The Ca(1)-O(3) bond length is 2.58 Å. The Ca(1)-O(4) bond length is 2.35 Å. The Ca(1)-O(5) bond length is 2.46 Å. The Ca(1)-O(6) bond length is 2.39 Å. There is one shorter (2.52 Å) and one longer (2.67 Å) Ca(1)-O(1) bond length. Ni(1) is bonded to one O(3), one O(4), two equivalent O(5), and two equivalent O(6) atoms to form NiO6 octahedra that share corners with three equivalent Ge(1)O4 tetrahedra, corners with two equivalent Ge(2)O5 trigonal bipyramids, edges with two equivalent Ni(1)O6 octahedra, and  an edgeedge with one Ge(2)O5 trigonal bipyramid. The Ni(1)-O(3) bond length is 2.30 Å. The Ni(1)-O(4) bond length is 2.04 Å. There is one shorter (2.05 Å) and one longer (2.13 Å) Ni(1)-O(5) bond length. There is one shorter (2.01 Å) and one longer (2.12 Å) Ni(1)-O(6) bond length. There are two inequivalent Ge sites. In the first Ge site, Ge(1) is bonded to one O(4), one O(5), and two equivalent O(2) atoms to form GeO4 tetrahedra that share corners with three equivalent Ni(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(4) bond length is 1.72 Å. The Ge(1)-O(5) bond length is 1.76 Å. There is one shorter (1.81 Å) and one longer (1.82 Å) Ge(1)-O(2) bond length. In the second Ge site, Ge(2) is bonded to one O(6), two equivalent O(1), and two equivalent O(3) atoms to form GeO5 trigonal bipyramids that share corners with two equivalent Ni(1)O6 octahedra, corners with two equivalent Ge(2)O5 trigonal bipyramids,  an edgeedge with one Ni(1)O6 octahedra, and  an edgeedge with one Ge(2)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles range from 41-43°. The Ge(2)-O(6) bond length is 1.78 Å. There is one shorter (1.80 Å) and one longer (1.91 Å) Ge(2)-O(1) bond length. There is one shorter (1.80 Å) and one longer (2.12 Å) Ge(2)-O(3) bond length. There are six inequivalent O sites. In the first O site, O(5) is bonded in a distorted rectangular see-saw-like geometry to one Ca(1), two equivalent Ni(1), and one Ge(1) atom. In the second O site, O(6) is bonded to one Ca(1), two equivalent Ni(1), and one Ge(2) atom to form distorted OCaNi2Ge tetrahedra that share corners with two equivalent O(6)CaNi2Ge tetrahedra and corners with four equivalent O(1)Ca2Ge2 tetrahedra. In the third O site, O(1) is bonded to two equivalent Ca(1) and two equivalent Ge(2) atoms to form distorted OCa2Ge2 tetrahedra that share corners with four equivalent O(6)CaNi2Ge tetrahedra and edges with two equivalent O(1)Ca2Ge2 tetrahedra. In the fourth O site, O(2) is bonded in a trigonal planar geometry to one Ca(1) and two equivalent Ge(1) atoms. In the fifth O site, O(3) is bonded in a distorted see-saw-like geometry to one Ca(1), one Ni(1), and two equivalent Ge(2) atoms. In the sixth O site, O(4) is bonded in a distorted trigonal planar geometry to one Ca(1), one Ni(1), and one Ge(1) atom.