Na2LaTaSi2SO12 crystallizes in the monoclinic Cc space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded in a 8-coordinate geometry to one O(10), one O(12), one O(4), one O(6), one O(7), one O(8), and two equivalent O(2) atoms. In the second Na site, Na(2) is bonded in a 5-coordinate geometry to one O(10), one O(11), one O(12), one O(7), and one O(8) atom. La(1) is bonded to one O(1), one O(2), one O(3), one O(7), one O(8), and one O(9) atom to form LaO6 octahedra that share corners with two equivalent Si(1)O4 tetrahedra, corners with two equivalent Si(2)O4 tetrahedra, and corners with two equivalent S(1)O4 tetrahedra. Ta(1) is bonded to one O(10), one O(11), one O(12), one O(4), one O(5), and one O(6) atom to form TaO6 octahedra that share corners with two equivalent Si(1)O4 tetrahedra, corners with two equivalent Si(2)O4 tetrahedra, and corners with two equivalent S(1)O4 tetrahedra. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(11), one O(2), one O(5), and one O(8) atom to form SiO4 tetrahedra that share corners with two equivalent La(1)O6 octahedra and corners with two equivalent Ta(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 15-38°. In the second Si site, Si(2) is bonded to one O(12), one O(3), one O(4), and one O(7) atom to form SiO4 tetrahedra that share corners with two equivalent La(1)O6 octahedra and corners with two equivalent Ta(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 23-36°. S(1) is bonded to one O(1), one O(10), one O(6), and one O(9) atom to form SO4 tetrahedra that share corners with two equivalent La(1)O6 octahedra and corners with two equivalent Ta(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 21-44°. There are twelve inequivalent O sites. In the first O site, O(1) is bonded in a bent 150 degrees geometry to one La(1) and one S(1) atom. In the second O site, O(2) is bonded in a 3-coordinate geometry to two equivalent Na(1), one La(1), and one Si(1) atom. In the third O site, O(3) is bonded in a bent 150 degrees geometry to one La(1) and one Si(2) atom. In the fourth O site, O(4) is bonded in a distorted bent 150 degrees geometry to one Na(1), one Ta(1), and one Si(2) atom. In the fifth O site, O(5) is bonded in a linear geometry to one Ta(1) and one Si(1) atom. In the sixth O site, O(6) is bonded in a distorted bent 150 degrees geometry to one Na(1), one Ta(1), and one S(1) atom. In the seventh O site, O(7) is bonded in a rectangular see-saw-like geometry to one Na(1), one Na(2), one La(1), and one Si(2) atom. In the eighth O site, O(8) is bonded in a 4-coordinate geometry to one Na(1), one Na(2), one La(1), and one Si(1) atom. In the ninth O site, O(9) is bonded in a distorted bent 150 degrees geometry to one La(1) and one S(1) atom. In the tenth O site, O(10) is bonded in a 4-coordinate geometry to one Na(1), one Na(2), one Ta(1), and one S(1) atom. In the eleventh O site, O(11) is bonded in a 3-coordinate geometry to one Na(2), one Ta(1), and one Si(1) atom. In the twelfth O site, O(12) is bonded in a 3-coordinate geometry to one Na(1), one Na(2), one Ta(1), and one Si(2) atom.
Na2LaTaSi2SO12 crystallizes in the monoclinic Cc space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded in a 8-coordinate geometry to one O(10), one O(12), one O(4), one O(6), one O(7), one O(8), and two equivalent O(2) atoms. The Na(1)-O(10) bond length is 2.48 Å. The Na(1)-O(12) bond length is 2.91 Å. The Na(1)-O(4) bond length is 2.91 Å. The Na(1)-O(6) bond length is 2.97 Å. The Na(1)-O(7) bond length is 2.29 Å. The Na(1)-O(8) bond length is 2.55 Å. There is one shorter (2.56 Å) and one longer (2.99 Å) Na(1)-O(2) bond length. In the second Na site, Na(2) is bonded in a 5-coordinate geometry to one O(10), one O(11), one O(12), one O(7), and one O(8) atom. The Na(2)-O(10) bond length is 2.70 Å. The Na(2)-O(11) bond length is 2.61 Å. The Na(2)-O(12) bond length is 2.51 Å. The Na(2)-O(7) bond length is 2.50 Å. The Na(2)-O(8) bond length is 2.93 Å. La(1) is bonded to one O(1), one O(2), one O(3), one O(7), one O(8), and one O(9) atom to form LaO6 octahedra that share corners with two equivalent Si(1)O4 tetrahedra, corners with two equivalent Si(2)O4 tetrahedra, and corners with two equivalent S(1)O4 tetrahedra. The La(1)-O(1) bond length is 2.42 Å. The La(1)-O(2) bond length is 2.24 Å. The La(1)-O(3) bond length is 2.17 Å. The La(1)-O(7) bond length is 2.41 Å. The La(1)-O(8) bond length is 2.25 Å. The La(1)-O(9) bond length is 2.48 Å. Ta(1) is bonded to one O(10), one O(11), one O(12), one O(4), one O(5), and one O(6) atom to form TaO6 octahedra that share corners with two equivalent Si(1)O4 tetrahedra, corners with two equivalent Si(2)O4 tetrahedra, and corners with two equivalent S(1)O4 tetrahedra. The Ta(1)-O(10) bond length is 2.16 Å. The Ta(1)-O(11) bond length is 1.99 Å. The Ta(1)-O(12) bond length is 2.00 Å. The Ta(1)-O(4) bond length is 1.98 Å. The Ta(1)-O(5) bond length is 1.97 Å. The Ta(1)-O(6) bond length is 2.25 Å. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(11), one O(2), one O(5), and one O(8) atom to form SiO4 tetrahedra that share corners with two equivalent La(1)O6 octahedra and corners with two equivalent Ta(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 15-38°. The Si(1)-O(11) bond length is 1.68 Å. The Si(1)-O(2) bond length is 1.60 Å. The Si(1)-O(5) bond length is 1.74 Å. The Si(1)-O(8) bond length is 1.61 Å. In the second Si site, Si(2) is bonded to one O(12), one O(3), one O(4), and one O(7) atom to form SiO4 tetrahedra that share corners with two equivalent La(1)O6 octahedra and corners with two equivalent Ta(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 23-36°. The Si(2)-O(12) bond length is 1.71 Å. The Si(2)-O(3) bond length is 1.58 Å. The Si(2)-O(4) bond length is 1.73 Å. The Si(2)-O(7) bond length is 1.61 Å. S(1) is bonded to one O(1), one O(10), one O(6), and one O(9) atom to form SO4 tetrahedra that share corners with two equivalent La(1)O6 octahedra and corners with two equivalent Ta(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 21-44°. The S(1)-O(1) bond length is 1.46 Å. The S(1)-O(10) bond length is 1.54 Å. The S(1)-O(6) bond length is 1.51 Å. The S(1)-O(9) bond length is 1.45 Å. There are twelve inequivalent O sites. In the first O site, O(1) is bonded in a bent 150 degrees geometry to one La(1) and one S(1) atom. In the second O site, O(2) is bonded in a 3-coordinate geometry to two equivalent Na(1), one La(1), and one Si(1) atom. In the third O site, O(3) is bonded in a bent 150 degrees geometry to one La(1) and one Si(2) atom. In the fourth O site, O(4) is bonded in a distorted bent 150 degrees geometry to one Na(1), one Ta(1), and one Si(2) atom. In the fifth O site, O(5) is bonded in a linear geometry to one Ta(1) and one Si(1) atom. In the sixth O site, O(6) is bonded in a distorted bent 150 degrees geometry to one Na(1), one Ta(1), and one S(1) atom. In the seventh O site, O(7) is bonded in a rectangular see-saw-like geometry to one Na(1), one Na(2), one La(1), and one Si(2) atom. In the eighth O site, O(8) is bonded in a 4-coordinate geometry to one Na(1), one Na(2), one La(1), and one Si(1) atom. In the ninth O site, O(9) is bonded in a distorted bent 150 degrees geometry to one La(1) and one S(1) atom. In the tenth O site, O(10) is bonded in a 4-coordinate geometry to one Na(1), one Na(2), one Ta(1), and one S(1) atom. In the eleventh O site, O(11) is bonded in a 3-coordinate geometry to one Na(2), one Ta(1), and one Si(1) atom. In the twelfth O site, O(12) is bonded in a 3-coordinate geometry to one Na(1), one Na(2), one Ta(1), and one Si(2) atom.