Ca8CoZn3(Si2O7)4 crystallizes in the tetragonal P-4 space group. There are two inequivalent Ca sites. In the first Ca site, Ca(1) is bonded in a 8-coordinate geometry to one O(1); one O(3); one O(7); two equivalent O(6); and three equivalent O(2,5) atoms. In the second Ca site, Ca(2) is bonded in a 8-coordinate geometry to one O(1); one O(2,5); one O(3); one O(6); two equivalent O(4); and two equivalent O(7) atoms. Co(1) is bonded to four equivalent O(4) atoms to form CoO4 tetrahedra that share corners with four equivalent Si(2)O4 tetrahedra. There are two inequivalent Zn sites. In the first Zn site, Zn(1) is bonded to two equivalent O(2,5) and two equivalent O(3) atoms to form ZnO4 tetrahedra that share corners with two equivalent Si(1)O4 tetrahedra and corners with two equivalent Si(2)O4 tetrahedra. In the second Zn site, Zn(2) is bonded to four equivalent O(2,5) atoms to form ZnO4 tetrahedra that share corners with four equivalent Si(1)O4 tetrahedra. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(1); one O(6); and two equivalent O(2,5) atoms to form SiO4 tetrahedra that share  a cornercorner with one Zn(1)O4 tetrahedra,  a cornercorner with one Zn(2)O4 tetrahedra, and  a cornercorner with one Si(2)O4 tetrahedra. In the second Si site, Si(2) is bonded to one O(1), one O(3), one O(4), and one O(7) atom to form SiO4 tetrahedra that share  a cornercorner with one Co(1)O4 tetrahedra,  a cornercorner with one Zn(1)O4 tetrahedra, and  a cornercorner with one Si(1)O4 tetrahedra. There are six inequivalent O sites. In the first O site, O(6) is bonded in a 4-coordinate geometry to one Ca(2), two equivalent Ca(1), and one Si(1) atom. In the second O site, O(7) is bonded in a 4-coordinate geometry to one Ca(1), two equivalent Ca(2), and one Si(2) atom. In the third O site, O(1) is bonded in a distorted tetrahedral geometry to one Ca(1), one Ca(2), one Si(1), and one Si(2) atom. In the fourth O site, O(2,5) is bonded in a 4-coordinate geometry to one Ca(1), one Ca(2), one Zn(1), and one Si(1) atom. In the fifth O site, O(3) is bonded in a 4-coordinate geometry to one Ca(1), one Ca(2), one Zn(1), and one Si(2) atom. In the sixth O site, O(4) is bonded in a 4-coordinate geometry to two equivalent Ca(2), one Co(1), and one Si(2) atom.
Ca8CoZn3(Si2O7)4 crystallizes in the tetragonal P-4 space group. There are two inequivalent Ca sites. In the first Ca site, Ca(1) is bonded in a 8-coordinate geometry to one O(1); one O(3); one O(7); two equivalent O(6); and three equivalent O(2,5) atoms. The Ca(1)-O(1) bond length is 2.50 Å. The Ca(1)-O(3) bond length is 2.72 Å. The Ca(1)-O(7) bond length is 2.74 Å. There is one shorter (2.48 Å) and one longer (2.73 Å) Ca(1)-O(6) bond length. There are two shorter (2.41 Å) and one longer (2.72 Å) Ca(1)-O(2,5) bond length. In the second Ca site, Ca(2) is bonded in a 8-coordinate geometry to one O(1); one O(2,5); one O(3); one O(6); two equivalent O(4); and two equivalent O(7) atoms. The Ca(2)-O(1) bond length is 2.50 Å. The Ca(2)-O(2,5) bond length is 2.73 Å. The Ca(2)-O(3) bond length is 2.41 Å. The Ca(2)-O(6) bond length is 2.73 Å. There is one shorter (2.41 Å) and one longer (2.72 Å) Ca(2)-O(4) bond length. There is one shorter (2.48 Å) and one longer (2.73 Å) Ca(2)-O(7) bond length. Co(1) is bonded to four equivalent O(4) atoms to form CoO4 tetrahedra that share corners with four equivalent Si(2)O4 tetrahedra. All Co(1)-O(4) bond lengths are 1.96 Å. There are two inequivalent Zn sites. In the first Zn site, Zn(1) is bonded to two equivalent O(2,5) and two equivalent O(3) atoms to form ZnO4 tetrahedra that share corners with two equivalent Si(1)O4 tetrahedra and corners with two equivalent Si(2)O4 tetrahedra. Both Zn(1)-O(2,5) bond lengths are 1.95 Å. Both Zn(1)-O(3) bond lengths are 1.95 Å. In the second Zn site, Zn(2) is bonded to four equivalent O(2,5) atoms to form ZnO4 tetrahedra that share corners with four equivalent Si(1)O4 tetrahedra. All Zn(2)-O(2,5) bond lengths are 1.95 Å. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(1); one O(6); and two equivalent O(2,5) atoms to form SiO4 tetrahedra that share  a cornercorner with one Zn(1)O4 tetrahedra,  a cornercorner with one Zn(2)O4 tetrahedra, and  a cornercorner with one Si(2)O4 tetrahedra. The Si(1)-O(1) bond length is 1.68 Å. The Si(1)-O(6) bond length is 1.61 Å. Both Si(1)-O(2,5) bond lengths are 1.65 Å. In the second Si site, Si(2) is bonded to one O(1), one O(3), one O(4), and one O(7) atom to form SiO4 tetrahedra that share  a cornercorner with one Co(1)O4 tetrahedra,  a cornercorner with one Zn(1)O4 tetrahedra, and  a cornercorner with one Si(1)O4 tetrahedra. The Si(2)-O(1) bond length is 1.68 Å. The Si(2)-O(3) bond length is 1.65 Å. The Si(2)-O(4) bond length is 1.65 Å. The Si(2)-O(7) bond length is 1.61 Å. There are six inequivalent O sites. In the first O site, O(6) is bonded in a 4-coordinate geometry to one Ca(2), two equivalent Ca(1), and one Si(1) atom. In the second O site, O(7) is bonded in a 4-coordinate geometry to one Ca(1), two equivalent Ca(2), and one Si(2) atom. In the third O site, O(1) is bonded in a distorted tetrahedral geometry to one Ca(1), one Ca(2), one Si(1), and one Si(2) atom. In the fourth O site, O(2,5) is bonded in a 4-coordinate geometry to one Ca(1), one Ca(2), one Zn(1), and one Si(1) atom. In the fifth O site, O(3) is bonded in a 4-coordinate geometry to one Ca(1), one Ca(2), one Zn(1), and one Si(2) atom. In the sixth O site, O(4) is bonded in a 4-coordinate geometry to two equivalent Ca(2), one Co(1), and one Si(2) atom.