Ta2Zn(CuO4)2 crystallizes in the monoclinic P2_1/c space group. There are two inequivalent Ta sites. In the first Ta site, Ta(1) is bonded to one O(1), one O(2), one O(4), and one O(7) atom to form TaO4 tetrahedra that share corners with three equivalent Zn(1)O6 octahedra and corners with two equivalent Cu(1)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 32-51°. In the second Ta site, Ta(2) is bonded to one O(3), one O(5), one O(6), and one O(8) atom to form TaO4 tetrahedra that share corners with three equivalent Zn(1)O6 octahedra and corners with three equivalent Cu(1)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 54-61°. There are two inequivalent Cu sites. In the first Cu site, Cu(1) is bonded to one O(1), one O(3), one O(5), one O(6), and one O(7) atom to form CuO5 trigonal bipyramids that share corners with two equivalent Ta(1)O4 tetrahedra, corners with three equivalent Ta(2)O4 tetrahedra, and edges with two equivalent Zn(1)O6 octahedra. In the second Cu site, Cu(2) is bonded in a rectangular see-saw-like geometry to one O(2), one O(4), one O(6), and one O(8) atom. Zn(1) is bonded to one O(1), one O(4), one O(7), one O(8), and two equivalent O(3) atoms to form ZnO6 octahedra that share corners with three equivalent Ta(1)O4 tetrahedra, corners with three equivalent Ta(2)O4 tetrahedra,  an edgeedge with one Zn(1)O6 octahedra, and edges with two equivalent Cu(1)O5 trigonal bipyramids. There are eight inequivalent O sites. In the first O site, O(7) is bonded in a 3-coordinate geometry to one Ta(1), one Cu(1), and one Zn(1) atom. In the second O site, O(8) is bonded in a distorted trigonal planar geometry to one Ta(2), one Cu(2), and one Zn(1) atom. In the third O site, O(1) is bonded in a distorted trigonal planar geometry to one Ta(1), one Cu(1), and one Zn(1) atom. In the fourth O site, O(2) is bonded in a bent 150 degrees geometry to one Ta(1) and one Cu(2) atom. In the fifth O site, O(3) is bonded in a distorted rectangular see-saw-like geometry to one Ta(2), one Cu(1), and two equivalent Zn(1) atoms. In the sixth O site, O(4) is bonded in a distorted trigonal planar geometry to one Ta(1), one Cu(2), and one Zn(1) atom. In the seventh O site, O(5) is bonded in a distorted bent 150 degrees geometry to one Ta(2) and one Cu(1) atom. In the eighth O site, O(6) is bonded in a 3-coordinate geometry to one Ta(2), one Cu(1), and one Cu(2) atom.
Ta2Zn(CuO4)2 crystallizes in the monoclinic P2_1/c space group. There are two inequivalent Ta sites. In the first Ta site, Ta(1) is bonded to one O(1), one O(2), one O(4), and one O(7) atom to form TaO4 tetrahedra that share corners with three equivalent Zn(1)O6 octahedra and corners with two equivalent Cu(1)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 32-51°. The Ta(1)-O(1) bond length is 1.90 Å. The Ta(1)-O(2) bond length is 1.84 Å. The Ta(1)-O(4) bond length is 1.90 Å. The Ta(1)-O(7) bond length is 1.84 Å. In the second Ta site, Ta(2) is bonded to one O(3), one O(5), one O(6), and one O(8) atom to form TaO4 tetrahedra that share corners with three equivalent Zn(1)O6 octahedra and corners with three equivalent Cu(1)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 54-61°. The Ta(2)-O(3) bond length is 1.91 Å. The Ta(2)-O(5) bond length is 1.82 Å. The Ta(2)-O(6) bond length is 1.92 Å. The Ta(2)-O(8) bond length is 1.86 Å. There are two inequivalent Cu sites. In the first Cu site, Cu(1) is bonded to one O(1), one O(3), one O(5), one O(6), and one O(7) atom to form CuO5 trigonal bipyramids that share corners with two equivalent Ta(1)O4 tetrahedra, corners with three equivalent Ta(2)O4 tetrahedra, and edges with two equivalent Zn(1)O6 octahedra. The Cu(1)-O(1) bond length is 1.93 Å. The Cu(1)-O(3) bond length is 2.07 Å. The Cu(1)-O(5) bond length is 1.90 Å. The Cu(1)-O(6) bond length is 2.03 Å. The Cu(1)-O(7) bond length is 2.32 Å. In the second Cu site, Cu(2) is bonded in a rectangular see-saw-like geometry to one O(2), one O(4), one O(6), and one O(8) atom. The Cu(2)-O(2) bond length is 1.92 Å. The Cu(2)-O(4) bond length is 1.95 Å. The Cu(2)-O(6) bond length is 2.05 Å. The Cu(2)-O(8) bond length is 1.97 Å. Zn(1) is bonded to one O(1), one O(4), one O(7), one O(8), and two equivalent O(3) atoms to form ZnO6 octahedra that share corners with three equivalent Ta(1)O4 tetrahedra, corners with three equivalent Ta(2)O4 tetrahedra,  an edgeedge with one Zn(1)O6 octahedra, and edges with two equivalent Cu(1)O5 trigonal bipyramids. The Zn(1)-O(1) bond length is 2.07 Å. The Zn(1)-O(4) bond length is 2.13 Å. The Zn(1)-O(7) bond length is 2.03 Å. The Zn(1)-O(8) bond length is 2.10 Å. There is one shorter (2.12 Å) and one longer (2.40 Å) Zn(1)-O(3) bond length. There are eight inequivalent O sites. In the first O site, O(7) is bonded in a 3-coordinate geometry to one Ta(1), one Cu(1), and one Zn(1) atom. In the second O site, O(8) is bonded in a distorted trigonal planar geometry to one Ta(2), one Cu(2), and one Zn(1) atom. In the third O site, O(1) is bonded in a distorted trigonal planar geometry to one Ta(1), one Cu(1), and one Zn(1) atom. In the fourth O site, O(2) is bonded in a bent 150 degrees geometry to one Ta(1) and one Cu(2) atom. In the fifth O site, O(3) is bonded in a distorted rectangular see-saw-like geometry to one Ta(2), one Cu(1), and two equivalent Zn(1) atoms. In the sixth O site, O(4) is bonded in a distorted trigonal planar geometry to one Ta(1), one Cu(2), and one Zn(1) atom. In the seventh O site, O(5) is bonded in a distorted bent 150 degrees geometry to one Ta(2) and one Cu(1) atom. In the eighth O site, O(6) is bonded in a 3-coordinate geometry to one Ta(2), one Cu(1), and one Cu(2) atom.