LaZrTa3O11 crystallizes in the monoclinic C2 space group. There are two inequivalent La sites. In the first La site, La(1) is bonded in a 8-coordinate geometry to two equivalent O(10), two equivalent O(4), two equivalent O(5), and two equivalent O(6) atoms. In the second La site, La(2) is bonded in a 8-coordinate geometry to two equivalent O(11), two equivalent O(7), two equivalent O(8), and two equivalent O(9) atoms. Zr(1) is bonded to one O(1), one O(10), one O(11), one O(2), one O(3), one O(6), and one O(7) atom to form distorted ZrO7 pentagonal bipyramids that share  a cornercorner with one Ta(3)O6 octahedra and  a cornercorner with one Ta(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 46-47°. There are four inequivalent Ta sites. In the first Ta site, Ta(1) is bonded in a 7-coordinate geometry to one O(1), one O(10), one O(11), one O(2), one O(3), one O(5), and one O(8) atom. In the second Ta site, Ta(2) is bonded in a 7-coordinate geometry to one O(1), one O(10), one O(11), one O(2), one O(3), one O(4), and one O(9) atom. In the third Ta site, Ta(3) is bonded to two equivalent O(7), two equivalent O(8), and two equivalent O(9) atoms to form TaO6 octahedra that share corners with two equivalent Zr(1)O7 pentagonal bipyramids. In the fourth Ta site, Ta(4) is bonded to two equivalent O(4), two equivalent O(5), and two equivalent O(6) atoms to form TaO6 octahedra that share corners with two equivalent Zr(1)O7 pentagonal bipyramids. There are eleven inequivalent O sites. In the first O site, O(10) is bonded to one La(1), one Zr(1), one Ta(1), and one Ta(2) atom to form distorted corner-sharing OLaZrTa2 tetrahedra. In the second O site, O(11) is bonded to one La(2), one Zr(1), one Ta(1), and one Ta(2) atom to form distorted corner-sharing OLaZrTa2 tetrahedra. In the third O site, O(1) is bonded in a 3-coordinate geometry to one Zr(1), one Ta(1), and one Ta(2) atom. In the fourth O site, O(2) is bonded in a distorted bent 150 degrees geometry to one Zr(1), one Ta(1), and one Ta(2) atom. In the fifth O site, O(3) is bonded in a distorted bent 150 degrees geometry to one Zr(1), one Ta(1), and one Ta(2) atom. In the sixth O site, O(4) is bonded in a distorted trigonal non-coplanar geometry to one La(1), one Ta(2), and one Ta(4) atom. In the seventh O site, O(5) is bonded in a 3-coordinate geometry to one La(1), one Ta(1), and one Ta(4) atom. In the eighth O site, O(6) is bonded in a distorted trigonal non-coplanar geometry to one La(1), one Zr(1), and one Ta(4) atom. In the ninth O site, O(7) is bonded in a distorted trigonal non-coplanar geometry to one La(2), one Zr(1), and one Ta(3) atom. In the tenth O site, O(8) is bonded in a 3-coordinate geometry to one La(2), one Ta(1), and one Ta(3) atom. In the eleventh O site, O(9) is bonded in a distorted trigonal non-coplanar geometry to one La(2), one Ta(2), and one Ta(3) atom.
LaZrTa3O11 crystallizes in the monoclinic C2 space group. There are two inequivalent La sites. In the first La site, La(1) is bonded in a 8-coordinate geometry to two equivalent O(10), two equivalent O(4), two equivalent O(5), and two equivalent O(6) atoms. Both La(1)-O(10) bond lengths are 2.63 Å. Both La(1)-O(4) bond lengths are 2.54 Å. Both La(1)-O(5) bond lengths are 2.56 Å. Both La(1)-O(6) bond lengths are 2.44 Å. In the second La site, La(2) is bonded in a 8-coordinate geometry to two equivalent O(11), two equivalent O(7), two equivalent O(8), and two equivalent O(9) atoms. Both La(2)-O(11) bond lengths are 2.63 Å. Both La(2)-O(7) bond lengths are 2.46 Å. Both La(2)-O(8) bond lengths are 2.55 Å. Both La(2)-O(9) bond lengths are 2.53 Å. Zr(1) is bonded to one O(1), one O(10), one O(11), one O(2), one O(3), one O(6), and one O(7) atom to form distorted ZrO7 pentagonal bipyramids that share  a cornercorner with one Ta(3)O6 octahedra and  a cornercorner with one Ta(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 46-47°. The Zr(1)-O(1) bond length is 2.51 Å. The Zr(1)-O(10) bond length is 2.13 Å. The Zr(1)-O(11) bond length is 2.14 Å. The Zr(1)-O(2) bond length is 2.10 Å. The Zr(1)-O(3) bond length is 2.08 Å. The Zr(1)-O(6) bond length is 2.11 Å. The Zr(1)-O(7) bond length is 2.12 Å. There are four inequivalent Ta sites. In the first Ta site, Ta(1) is bonded in a 7-coordinate geometry to one O(1), one O(10), one O(11), one O(2), one O(3), one O(5), and one O(8) atom. The Ta(1)-O(1) bond length is 2.02 Å. The Ta(1)-O(10) bond length is 2.08 Å. The Ta(1)-O(11) bond length is 2.12 Å. The Ta(1)-O(2) bond length is 2.51 Å. The Ta(1)-O(3) bond length is 1.94 Å. The Ta(1)-O(5) bond length is 1.99 Å. The Ta(1)-O(8) bond length is 2.00 Å. In the second Ta site, Ta(2) is bonded in a 7-coordinate geometry to one O(1), one O(10), one O(11), one O(2), one O(3), one O(4), and one O(9) atom. The Ta(2)-O(1) bond length is 2.01 Å. The Ta(2)-O(10) bond length is 2.11 Å. The Ta(2)-O(11) bond length is 2.08 Å. The Ta(2)-O(2) bond length is 1.94 Å. The Ta(2)-O(3) bond length is 2.52 Å. The Ta(2)-O(4) bond length is 2.02 Å. The Ta(2)-O(9) bond length is 2.00 Å. In the third Ta site, Ta(3) is bonded to two equivalent O(7), two equivalent O(8), and two equivalent O(9) atoms to form TaO6 octahedra that share corners with two equivalent Zr(1)O7 pentagonal bipyramids. Both Ta(3)-O(7) bond lengths are 1.95 Å. Both Ta(3)-O(8) bond lengths are 2.02 Å. Both Ta(3)-O(9) bond lengths are 2.04 Å. In the fourth Ta site, Ta(4) is bonded to two equivalent O(4), two equivalent O(5), and two equivalent O(6) atoms to form TaO6 octahedra that share corners with two equivalent Zr(1)O7 pentagonal bipyramids. Both Ta(4)-O(4) bond lengths are 2.00 Å. Both Ta(4)-O(5) bond lengths are 2.02 Å. Both Ta(4)-O(6) bond lengths are 1.98 Å. There are eleven inequivalent O sites. In the first O site, O(10) is bonded to one La(1), one Zr(1), one Ta(1), and one Ta(2) atom to form distorted corner-sharing OLaZrTa2 tetrahedra. In the second O site, O(11) is bonded to one La(2), one Zr(1), one Ta(1), and one Ta(2) atom to form distorted corner-sharing OLaZrTa2 tetrahedra. In the third O site, O(1) is bonded in a 3-coordinate geometry to one Zr(1), one Ta(1), and one Ta(2) atom. In the fourth O site, O(2) is bonded in a distorted bent 150 degrees geometry to one Zr(1), one Ta(1), and one Ta(2) atom. In the fifth O site, O(3) is bonded in a distorted bent 150 degrees geometry to one Zr(1), one Ta(1), and one Ta(2) atom. In the sixth O site, O(4) is bonded in a distorted trigonal non-coplanar geometry to one La(1), one Ta(2), and one Ta(4) atom. In the seventh O site, O(5) is bonded in a 3-coordinate geometry to one La(1), one Ta(1), and one Ta(4) atom. In the eighth O site, O(6) is bonded in a distorted trigonal non-coplanar geometry to one La(1), one Zr(1), and one Ta(4) atom. In the ninth O site, O(7) is bonded in a distorted trigonal non-coplanar geometry to one La(2), one Zr(1), and one Ta(3) atom. In the tenth O site, O(8) is bonded in a 3-coordinate geometry to one La(2), one Ta(1), and one Ta(3) atom. In the eleventh O site, O(9) is bonded in a distorted trigonal non-coplanar geometry to one La(2), one Ta(2), and one Ta(3) atom.