ZnTlAsO4 crystallizes in the monoclinic P2_1 space group. There are two inequivalent Zn sites. In the first Zn site, Zn(1) is bonded to one O(1), one O(2), one O(5), and one O(7) atom to form 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(3), one O(4), one O(6), and one O(8) atom to form ZnO4 tetrahedra that share  a cornercorner with one As(2)O4 tetrahedra and corners with three equivalent As(1)O4 tetrahedra. There are two inequivalent Tl sites. In the first Tl site, Tl(1) is bonded in a 3-coordinate geometry to one O(1), one O(4), and one O(8) atom. In the second Tl site, Tl(2) is bonded in a distorted L-shaped geometry to one O(3) and one O(6) atom. There are two inequivalent As sites. In the first As site, As(1) is bonded to one O(1), one O(3), one O(6), and one O(8) atom to form AsO4 tetrahedra that share  a cornercorner with one Zn(1)O4 tetrahedra and corners with three equivalent Zn(2)O4 tetrahedra. In the second As site, As(2) is bonded to one O(2), one O(4), one O(5), and one O(7) atom to form AsO4 tetrahedra that share  a cornercorner with one Zn(2)O4 tetrahedra and corners with three equivalent Zn(1)O4 tetrahedra. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a distorted bent 120 degrees geometry to one Zn(1), one Tl(1), and one As(1) atom. In the second O site, O(2) is bonded in a distorted bent 120 degrees geometry to one Zn(1) and one As(2) atom. In the third O site, O(3) is bonded in a distorted bent 120 degrees geometry to one Zn(2), one Tl(2), and one As(1) atom. In the fourth O site, O(4) is bonded in a distorted bent 120 degrees geometry to one Zn(2), one Tl(1), and one As(2) atom. In the fifth O site, O(5) is bonded in a bent 120 degrees geometry to one Zn(1) and one As(2) atom. In the sixth O site, O(6) is bonded in a 3-coordinate geometry to one Zn(2), one Tl(2), and one As(1) atom. In the seventh O site, O(7) is bonded in a bent 120 degrees geometry to one Zn(1) and one As(2) atom. In the eighth O site, O(8) is bonded in a distorted trigonal planar geometry to one Zn(2), one Tl(1), and one As(1) atom.
ZnTlAsO4 crystallizes in the monoclinic P2_1 space group. There are two inequivalent Zn sites. In the first Zn site, Zn(1) is bonded to one O(1), one O(2), one O(5), and one O(7) atom to form 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(1) bond length is 1.96 Å. The Zn(1)-O(2) bond length is 1.95 Å. The Zn(1)-O(5) bond length is 1.97 Å. The Zn(1)-O(7) bond length is 1.95 Å. In the second Zn site, Zn(2) is bonded to one O(3), one O(4), one O(6), and one O(8) atom to form ZnO4 tetrahedra that share  a cornercorner with one As(2)O4 tetrahedra and corners with three equivalent As(1)O4 tetrahedra. The Zn(2)-O(3) bond length is 1.96 Å. The Zn(2)-O(4) bond length is 1.93 Å. The Zn(2)-O(6) bond length is 1.97 Å. The Zn(2)-O(8) bond length is 1.96 Å. There are two inequivalent Tl sites. In the first Tl site, Tl(1) is bonded in a 3-coordinate geometry to one O(1), one O(4), and one O(8) atom. The Tl(1)-O(1) bond length is 2.78 Å. The Tl(1)-O(4) bond length is 2.71 Å. The Tl(1)-O(8) bond length is 2.69 Å. In the second Tl site, Tl(2) is bonded in a distorted L-shaped geometry to one O(3) and one O(6) atom. The Tl(2)-O(3) bond length is 2.80 Å. The Tl(2)-O(6) bond length is 2.70 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(6), and one O(8) atom to form AsO4 tetrahedra that share  a cornercorner with one Zn(1)O4 tetrahedra and corners with three equivalent Zn(2)O4 tetrahedra. The As(1)-O(1) bond length is 1.70 Å. The As(1)-O(3) bond length is 1.70 Å. The As(1)-O(6) bond length is 1.70 Å. The As(1)-O(8) bond length is 1.71 Å. In the second As site, As(2) is bonded to one O(2), one O(4), one O(5), and one O(7) atom to form AsO4 tetrahedra that share  a cornercorner with one Zn(2)O4 tetrahedra and corners with three equivalent Zn(1)O4 tetrahedra. The As(2)-O(2) bond length is 1.70 Å. The As(2)-O(4) bond length is 1.70 Å. The As(2)-O(5) bond length is 1.70 Å. The As(2)-O(7) bond length is 1.70 Å. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a distorted bent 120 degrees geometry to one Zn(1), one Tl(1), and one As(1) atom. In the second O site, O(2) is bonded in a distorted bent 120 degrees geometry to one Zn(1) and one As(2) atom. In the third O site, O(3) is bonded in a distorted bent 120 degrees geometry to one Zn(2), one Tl(2), and one As(1) atom. In the fourth O site, O(4) is bonded in a distorted bent 120 degrees geometry to one Zn(2), one Tl(1), and one As(2) atom. In the fifth O site, O(5) is bonded in a bent 120 degrees geometry to one Zn(1) and one As(2) atom. In the sixth O site, O(6) is bonded in a 3-coordinate geometry to one Zn(2), one Tl(2), and one As(1) atom. In the seventh O site, O(7) is bonded in a bent 120 degrees geometry to one Zn(1) and one As(2) atom. In the eighth O site, O(8) is bonded in a distorted trigonal planar geometry to one Zn(2), one Tl(1), and one As(1) atom.