Ca2Zn4As4O17 crystallizes in the monoclinic C2/c space group. Ca(1) is bonded in a 8-coordinate geometry to one O(1), one O(2), one O(4), one O(5), one O(6), one O(7), one O(8), and one O(9) atom. There are two inequivalent Zn sites. In the first Zn site, Zn(1) is bonded to one O(2), one O(6), one O(7), and one O(8) atom to form distorted ZnO4 tetrahedra that share  a cornercorner with one As(1)O4 tetrahedra and corners with three equivalent As(2)O4 tetrahedra. In the second Zn site, Zn(2) is bonded to one O(1), one O(4), one O(5), and two equivalent O(3) atoms to form ZnO5 trigonal bipyramids that share  a cornercorner with one As(2)O4 tetrahedra, corners with four equivalent As(1)O4 tetrahedra, and  an edgeedge with one Zn(2)O5 trigonal bipyramid. There are two inequivalent As sites. In the first As site, As(1) is bonded to one O(1), one O(3), one O(5), and one O(7) atom to form AsO4 tetrahedra that share  a cornercorner with one Zn(1)O4 tetrahedra and corners with four equivalent Zn(2)O5 trigonal bipyramids. In the second As site, As(2) is bonded to one O(2), one O(4), one O(6), and one O(8) atom to form AsO4 tetrahedra that share corners with three equivalent Zn(1)O4 tetrahedra and  a cornercorner with one Zn(2)O5 trigonal bipyramid. There are nine inequivalent O sites. In the first O site, O(7) is bonded in a distorted trigonal planar geometry to one Ca(1), one Zn(1), and one As(1) atom. In the second O site, O(8) is bonded in a distorted trigonal planar geometry to one Ca(1), one Zn(1), and one As(2) atom. In the third O site, O(1) is bonded in a distorted trigonal non-coplanar geometry to one Ca(1), one Zn(2), and one As(1) atom. In the fourth O site, O(9) is bonded in a bent 150 degrees geometry to two equivalent Ca(1) atoms. In the fifth O site, O(2) is bonded in a 3-coordinate geometry to one Ca(1), one Zn(1), and one As(2) atom. In the sixth O site, O(6) is bonded in a 3-coordinate geometry to one Ca(1), one Zn(1), and one As(2) atom. In the seventh O site, O(3) is bonded in a distorted trigonal planar geometry to two equivalent Zn(2) and one As(1) atom. In the eighth O site, O(4) is bonded in a 3-coordinate geometry to one Ca(1), one Zn(2), and one As(2) atom. In the ninth O site, O(5) is bonded in a distorted bent 120 degrees geometry to one Ca(1), one Zn(2), and one As(1) atom.
Ca2Zn4As4O17 crystallizes in the monoclinic C2/c space group. Ca(1) is bonded in a 8-coordinate geometry to one O(1), one O(2), one O(4), one O(5), one O(6), one O(7), one O(8), and one O(9) atom. The Ca(1)-O(1) bond length is 2.34 Å. The Ca(1)-O(2) bond length is 2.51 Å. The Ca(1)-O(4) bond length is 2.64 Å. The Ca(1)-O(5) bond length is 2.91 Å. The Ca(1)-O(6) bond length is 2.57 Å. The Ca(1)-O(7) bond length is 2.38 Å. The Ca(1)-O(8) bond length is 2.42 Å. The Ca(1)-O(9) bond length is 2.34 Å. There are two inequivalent Zn sites. In the first Zn site, Zn(1) is bonded to one O(2), one O(6), one O(7), and one O(8) atom to form distorted ZnO4 tetrahedra that share  a cornercorner with one As(1)O4 tetrahedra and corners with three equivalent As(2)O4 tetrahedra. The Zn(1)-O(2) bond length is 1.95 Å. The Zn(1)-O(6) bond length is 2.04 Å. The Zn(1)-O(7) bond length is 1.96 Å. The Zn(1)-O(8) bond length is 2.04 Å. In the second Zn site, Zn(2) is bonded to one O(1), one O(4), one O(5), and two equivalent O(3) atoms to form ZnO5 trigonal bipyramids that share  a cornercorner with one As(2)O4 tetrahedra, corners with four equivalent As(1)O4 tetrahedra, and  an edgeedge with one Zn(2)O5 trigonal bipyramid. The Zn(2)-O(1) bond length is 2.03 Å. The Zn(2)-O(4) bond length is 2.10 Å. The Zn(2)-O(5) bond length is 2.02 Å. Both Zn(2)-O(3) bond lengths are 2.05 Å. There are two inequivalent As sites. In the first As site, As(1) is bonded to one O(1), one O(3), one O(5), and one O(7) atom to form AsO4 tetrahedra that share  a cornercorner with one Zn(1)O4 tetrahedra and corners with four equivalent Zn(2)O5 trigonal bipyramids. The As(1)-O(1) bond length is 1.72 Å. The As(1)-O(3) bond length is 1.72 Å. The As(1)-O(5) bond length is 1.71 Å. The As(1)-O(7) bond length is 1.73 Å. In the second As site, As(2) is bonded to one O(2), one O(4), one O(6), and one O(8) atom to form AsO4 tetrahedra that share corners with three equivalent Zn(1)O4 tetrahedra and  a cornercorner with one Zn(2)O5 trigonal bipyramid. The As(2)-O(2) bond length is 1.73 Å. The As(2)-O(4) bond length is 1.71 Å. The As(2)-O(6) bond length is 1.76 Å. The As(2)-O(8) bond length is 1.72 Å. There are nine inequivalent O sites. In the first O site, O(7) is bonded in a distorted trigonal planar geometry to one Ca(1), one Zn(1), and one As(1) atom. In the second O site, O(8) is bonded in a distorted trigonal planar geometry to one Ca(1), one Zn(1), and one As(2) atom. In the third O site, O(1) is bonded in a distorted trigonal non-coplanar geometry to one Ca(1), one Zn(2), and one As(1) atom. In the fourth O site, O(9) is bonded in a bent 150 degrees geometry to two equivalent Ca(1) atoms. In the fifth O site, O(2) is bonded in a 3-coordinate geometry to one Ca(1), one Zn(1), and one As(2) atom. In the sixth O site, O(6) is bonded in a 3-coordinate geometry to one Ca(1), one Zn(1), and one As(2) atom. In the seventh O site, O(3) is bonded in a distorted trigonal planar geometry to two equivalent Zn(2) and one As(1) atom. In the eighth O site, O(4) is bonded in a 3-coordinate geometry to one Ca(1), one Zn(2), and one As(2) atom. In the ninth O site, O(5) is bonded in a distorted bent 120 degrees geometry to one Ca(1), one Zn(2), and one As(1) atom.