Na3LaHfSi(PO6)2 crystallizes in the monoclinic Cc space group. There are three inequivalent Na sites. In the first Na site, Na(1) is bonded in a 6-coordinate geometry to one O(1), one O(11), one O(12), one O(2), one O(5), and one O(6) atom. In the second Na site, Na(2) is bonded in a 5-coordinate geometry to one O(1), one O(10), one O(11), one O(2), and one O(9) atom. In the third Na site, Na(3) is bonded in a 5-coordinate geometry to one O(11), one O(5), one O(6), one O(7), and one O(8) atom. La(1) is bonded to one O(1), one O(11), one O(4), one O(5), 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 P(1)O4 tetrahedra, and corners with two equivalent P(2)O4 tetrahedra. Hf(1) is bonded to one O(10), one O(12), one O(2), one O(3), one O(6), and one O(7) atom to form HfO6 octahedra that share corners with two equivalent Si(1)O4 tetrahedra, corners with two equivalent P(1)O4 tetrahedra, and corners with two equivalent P(2)O4 tetrahedra. Si(1) is bonded to one O(1), one O(10), one O(6), and one O(8) atom to form SiO4 tetrahedra that share corners with two equivalent La(1)O6 octahedra and corners with two equivalent Hf(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 19-44°. There are two inequivalent P sites. In the first P site, P(1) is bonded to one O(11), one O(12), one O(3), and one O(4) atom to form PO4 tetrahedra that share corners with two equivalent La(1)O6 octahedra and corners with two equivalent Hf(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 17-43°. In the second P site, P(2) is bonded to one O(2), one O(5), one O(7), and one O(9) atom to form PO4 tetrahedra that share corners with two equivalent La(1)O6 octahedra and corners with two equivalent Hf(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 23-46°. There are twelve inequivalent O sites. In the first O site, O(1) is bonded in a rectangular see-saw-like geometry to one Na(1), one Na(2), one La(1), and one Si(1) atom. In the second O site, O(2) is bonded in a 4-coordinate geometry to one Na(1), one Na(2), one Hf(1), and one P(2) atom. In the third O site, O(3) is bonded in a linear geometry to one Hf(1) and one P(1) atom. In the fourth O site, O(4) is bonded in a distorted bent 150 degrees geometry to one La(1) and one P(1) atom. In the fifth O site, O(5) is bonded in a 3-coordinate geometry to one Na(1), one Na(3), one La(1), and one P(2) atom. In the sixth O site, O(6) is bonded in a 4-coordinate geometry to one Na(1), one Na(3), one Hf(1), and one Si(1) atom. In the seventh O site, O(7) is bonded in a 3-coordinate geometry to one Na(3), one Hf(1), and one P(2) atom. In the eighth O site, O(8) is bonded in a 3-coordinate geometry to one Na(3), one La(1), and one Si(1) atom. In the ninth O site, O(9) is bonded in a 1-coordinate geometry to one Na(2), one La(1), and one P(2) atom. In the tenth O site, O(10) is bonded in a 3-coordinate geometry to one Na(2), one Hf(1), and one Si(1) atom. In the eleventh O site, O(11) is bonded in a 1-coordinate geometry to one Na(1), one Na(2), one Na(3), one La(1), and one P(1) atom. In the twelfth O site, O(12) is bonded in a 3-coordinate geometry to one Na(1), one Hf(1), and one P(1) atom.
Na3LaHfSi(PO6)2 crystallizes in the monoclinic Cc space group. There are three inequivalent Na sites. In the first Na site, Na(1) is bonded in a 6-coordinate geometry to one O(1), one O(11), one O(12), one O(2), one O(5), and one O(6) atom. The Na(1)-O(1) bond length is 2.49 Å. The Na(1)-O(11) bond length is 3.01 Å. The Na(1)-O(12) bond length is 2.33 Å. The Na(1)-O(2) bond length is 2.58 Å. The Na(1)-O(5) bond length is 3.01 Å. The Na(1)-O(6) bond length is 2.37 Å. In the second Na site, Na(2) is bonded in a 5-coordinate geometry to one O(1), one O(10), one O(11), one O(2), and one O(9) atom. The Na(2)-O(1) bond length is 2.44 Å. The Na(2)-O(10) bond length is 2.71 Å. The Na(2)-O(11) bond length is 2.71 Å. The Na(2)-O(2) bond length is 2.40 Å. The Na(2)-O(9) bond length is 2.78 Å. In the third Na site, Na(3) is bonded in a 5-coordinate geometry to one O(11), one O(5), one O(6), one O(7), and one O(8) atom. The Na(3)-O(11) bond length is 2.71 Å. The Na(3)-O(5) bond length is 2.44 Å. The Na(3)-O(6) bond length is 2.55 Å. The Na(3)-O(7) bond length is 2.51 Å. The Na(3)-O(8) bond length is 2.58 Å. La(1) is bonded to one O(1), one O(11), one O(4), one O(5), 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 P(1)O4 tetrahedra, and corners with two equivalent P(2)O4 tetrahedra. The La(1)-O(1) bond length is 2.36 Å. The La(1)-O(11) bond length is 2.41 Å. The La(1)-O(4) bond length is 2.34 Å. The La(1)-O(5) bond length is 2.44 Å. The La(1)-O(8) bond length is 2.16 Å. The La(1)-O(9) bond length is 2.37 Å. Hf(1) is bonded to one O(10), one O(12), one O(2), one O(3), one O(6), and one O(7) atom to form HfO6 octahedra that share corners with two equivalent Si(1)O4 tetrahedra, corners with two equivalent P(1)O4 tetrahedra, and corners with two equivalent P(2)O4 tetrahedra. The Hf(1)-O(10) bond length is 2.06 Å. The Hf(1)-O(12) bond length is 2.12 Å. The Hf(1)-O(2) bond length is 2.22 Å. The Hf(1)-O(3) bond length is 2.07 Å. The Hf(1)-O(6) bond length is 2.09 Å. The Hf(1)-O(7) bond length is 2.25 Å. Si(1) is bonded to one O(1), one O(10), one O(6), and one O(8) atom to form SiO4 tetrahedra that share corners with two equivalent La(1)O6 octahedra and corners with two equivalent Hf(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 19-44°. The Si(1)-O(1) bond length is 1.63 Å. The Si(1)-O(10) bond length is 1.68 Å. The Si(1)-O(6) bond length is 1.66 Å. The Si(1)-O(8) bond length is 1.61 Å. There are two inequivalent P sites. In the first P site, P(1) is bonded to one O(11), one O(12), one O(3), and one O(4) atom to form PO4 tetrahedra that share corners with two equivalent La(1)O6 octahedra and corners with two equivalent Hf(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 17-43°. The P(1)-O(11) bond length is 1.55 Å. The P(1)-O(12) bond length is 1.56 Å. The P(1)-O(3) bond length is 1.58 Å. The P(1)-O(4) bond length is 1.52 Å. In the second P site, P(2) is bonded to one O(2), one O(5), one O(7), and one O(9) atom to form PO4 tetrahedra that share corners with two equivalent La(1)O6 octahedra and corners with two equivalent Hf(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 23-46°. The P(2)-O(2) bond length is 1.58 Å. The P(2)-O(5) bond length is 1.54 Å. The P(2)-O(7) bond length is 1.60 Å. The P(2)-O(9) bond length is 1.53 Å. There are twelve inequivalent O sites. In the first O site, O(1) is bonded in a rectangular see-saw-like geometry to one Na(1), one Na(2), one La(1), and one Si(1) atom. In the second O site, O(2) is bonded in a 4-coordinate geometry to one Na(1), one Na(2), one Hf(1), and one P(2) atom. In the third O site, O(3) is bonded in a linear geometry to one Hf(1) and one P(1) atom. In the fourth O site, O(4) is bonded in a distorted bent 150 degrees geometry to one La(1) and one P(1) atom. In the fifth O site, O(5) is bonded in a 3-coordinate geometry to one Na(1), one Na(3), one La(1), and one P(2) atom. In the sixth O site, O(6) is bonded in a 4-coordinate geometry to one Na(1), one Na(3), one Hf(1), and one Si(1) atom. In the seventh O site, O(7) is bonded in a 3-coordinate geometry to one Na(3), one Hf(1), and one P(2) atom. In the eighth O site, O(8) is bonded in a 3-coordinate geometry to one Na(3), one La(1), and one Si(1) atom. In the ninth O site, O(9) is bonded in a 1-coordinate geometry to one Na(2), one La(1), and one P(2) atom. In the tenth O site, O(10) is bonded in a 3-coordinate geometry to one Na(2), one Hf(1), and one Si(1) atom. In the eleventh O site, O(11) is bonded in a 1-coordinate geometry to one Na(1), one Na(2), one Na(3), one La(1), and one P(1) atom. In the twelfth O site, O(12) is bonded in a 3-coordinate geometry to one Na(1), one Hf(1), and one P(1) atom.