Sr2LaTa3O11 crystallizes in the orthorhombic Immm space group. Sr(1) is bonded in a 6-coordinate geometry to six equivalent O(2) atoms. La(1) is bonded to two equivalent O(3), two equivalent O(4), and eight equivalent O(1) atoms to form LaO12 cuboctahedra that share corners with two equivalent La(1)O12 cuboctahedra, faces with two equivalent La(1)O12 cuboctahedra, faces with four equivalent Ta(1)O6 octahedra, and faces with four equivalent Ta(2)O6 octahedra. There are two inequivalent Ta sites. In the first Ta site, Ta(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(4) atoms to form TaO6 octahedra that share corners with two equivalent Ta(1)O6 octahedra, corners with two equivalent Ta(2)O6 octahedra, and faces with two equivalent La(1)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 10-19°. In the second Ta site, Ta(2) is bonded to two equivalent O(3) and four equivalent O(1) atoms to form TaO6 octahedra that share corners with two equivalent Ta(2)O6 octahedra, corners with four equivalent Ta(1)O6 octahedra, and faces with four equivalent La(1)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 0-10°. There are four inequivalent O sites. In the first O site, O(1) is bonded in a distorted rectangular see-saw-like geometry to two equivalent La(1), one Ta(1), and one Ta(2) atom. In the second O site, O(2) is bonded to three equivalent Sr(1) and one Ta(1) atom to form a mixture of distorted corner and edge-sharing OSr3Ta tetrahedra. In the third O site, O(3) is bonded in a distorted linear geometry to two equivalent La(1) and two equivalent Ta(2) atoms. In the fourth O site, O(4) is bonded in a distorted T-shaped geometry to one La(1) and two equivalent Ta(1) atoms.
Sr2LaTa3O11 crystallizes in the orthorhombic Immm space group. Sr(1) is bonded in a 6-coordinate geometry to six equivalent O(2) atoms. There are four shorter (2.51 Å) and two longer (2.59 Å) Sr(1)-O(2) bond lengths. La(1) is bonded to two equivalent O(3), two equivalent O(4), and eight equivalent O(1) atoms to form LaO12 cuboctahedra that share corners with two equivalent La(1)O12 cuboctahedra, faces with two equivalent La(1)O12 cuboctahedra, faces with four equivalent Ta(1)O6 octahedra, and faces with four equivalent Ta(2)O6 octahedra. Both La(1)-O(3) bond lengths are 2.88 Å. Both La(1)-O(4) bond lengths are 2.62 Å. All La(1)-O(1) bond lengths are 2.74 Å. There are two inequivalent Ta sites. In the first Ta site, Ta(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(4) atoms to form TaO6 octahedra that share corners with two equivalent Ta(1)O6 octahedra, corners with two equivalent Ta(2)O6 octahedra, and faces with two equivalent La(1)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 10-19°. Both Ta(1)-O(1) bond lengths are 2.14 Å. Both Ta(1)-O(2) bond lengths are 1.89 Å. Both Ta(1)-O(4) bond lengths are 2.02 Å. In the second Ta site, Ta(2) is bonded to two equivalent O(3) and four equivalent O(1) atoms to form TaO6 octahedra that share corners with two equivalent Ta(2)O6 octahedra, corners with four equivalent Ta(1)O6 octahedra, and faces with four equivalent La(1)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 0-10°. Both Ta(2)-O(3) bond lengths are 1.99 Å. All Ta(2)-O(1) bond lengths are 2.00 Å. There are four inequivalent O sites. In the first O site, O(1) is bonded in a distorted rectangular see-saw-like geometry to two equivalent La(1), one Ta(1), and one Ta(2) atom. In the second O site, O(2) is bonded to three equivalent Sr(1) and one Ta(1) atom to form a mixture of distorted corner and edge-sharing OSr3Ta tetrahedra. In the third O site, O(3) is bonded in a distorted linear geometry to two equivalent La(1) and two equivalent Ta(2) atoms. In the fourth O site, O(4) is bonded in a distorted T-shaped geometry to one La(1) and two equivalent Ta(1) atoms.