Na3HfTa(GeO4)3 crystallizes in the monoclinic Cc space group. There are three inequivalent Na sites. In the first Na site, Na(1) is bonded in a distorted hexagonal planar 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 6-coordinate geometry to one O(1), one O(10), one O(11), one O(12), one O(2), and one O(9) atom. In the third Na site, Na(3) is bonded in a 7-coordinate geometry to one O(11), one O(2), one O(5), one O(6), one O(7), and two equivalent O(4) atoms. Hf(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 HfO6 octahedra that share corners with two equivalent Ge(1)O4 tetrahedra, corners with two equivalent Ge(2)O4 tetrahedra, and corners with two equivalent Ge(3)O4 tetrahedra. Ta(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 TaO6 octahedra that share corners with two equivalent Ge(1)O4 tetrahedra, corners with two equivalent Ge(2)O4 tetrahedra, and corners with two equivalent Ge(3)O4 tetrahedra. There are three inequivalent Ge sites. In the first Ge site, Ge(1) is bonded to one O(11), one O(12), one O(3), and one O(4) atom to form GeO4 tetrahedra that share corners with two equivalent Hf(1)O6 octahedra and corners with two equivalent Ta(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 19-42°. In the second Ge site, Ge(2) is bonded to one O(2), one O(5), one O(7), and one O(9) atom to form GeO4 tetrahedra that share corners with two equivalent Hf(1)O6 octahedra and corners with two equivalent Ta(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 26-41°. In the third Ge site, Ge(3) is bonded to one O(1), one O(10), one O(6), and one O(8) atom to form GeO4 tetrahedra that share corners with two equivalent Hf(1)O6 octahedra and corners with two equivalent Ta(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 17-40°. 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 Hf(1), and one Ge(3) atom. In the second O site, O(2) is bonded in a 5-coordinate geometry to one Na(1), one Na(2), one Na(3), one Ta(1), and one Ge(2) atom. In the third O site, O(3) is bonded in a bent 150 degrees geometry to one Ta(1) and one Ge(1) atom. In the fourth O site, O(4) is bonded in a distorted bent 150 degrees geometry to two equivalent Na(3), one Hf(1), and one Ge(1) atom. In the fifth O site, O(5) is bonded in a rectangular see-saw-like geometry to one Na(1), one Na(3), one Hf(1), and one Ge(2) atom. In the sixth O site, O(6) is bonded to one Na(1), one Na(3), one Ta(1), and one Ge(3) atom to form distorted corner-sharing ONa2TaGe trigonal pyramids. In the seventh O site, O(7) is bonded in a 3-coordinate geometry to one Na(3), one Ta(1), and one Ge(2) atom. In the eighth O site, O(8) is bonded in a linear geometry to one Hf(1) and one Ge(3) atom. In the ninth O site, O(9) is bonded in a 3-coordinate geometry to one Na(2), one Hf(1), and one Ge(2) atom. In the tenth O site, O(10) is bonded in a 3-coordinate geometry to one Na(2), one Ta(1), and one Ge(3) atom. In the eleventh O site, O(11) is bonded to one Na(1), one Na(2), one Na(3), one Hf(1), and one Ge(1) atom to form distorted corner-sharing ONa3HfGe trigonal bipyramids. In the twelfth O site, O(12) is bonded in a distorted rectangular see-saw-like geometry to one Na(1), one Na(2), one Ta(1), and one Ge(1) atom.
Na3HfTa(GeO4)3 crystallizes in the monoclinic Cc space group. There are three inequivalent Na sites. In the first Na site, Na(1) is bonded in a distorted hexagonal planar 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 2.40 Å. The Na(1)-O(11) bond length is 2.70 Å. The Na(1)-O(12) bond length is 2.38 Å. The Na(1)-O(2) bond length is 2.68 Å. The Na(1)-O(5) bond length is 2.49 Å. The Na(1)-O(6) bond length is 2.51 Å. In the second Na site, Na(2) is bonded in a 6-coordinate geometry to one O(1), one O(10), one O(11), one O(12), one O(2), and one O(9) atom. The Na(2)-O(1) bond length is 2.52 Å. The Na(2)-O(10) bond length is 2.66 Å. The Na(2)-O(11) bond length is 2.54 Å. The Na(2)-O(12) bond length is 2.68 Å. The Na(2)-O(2) bond length is 2.51 Å. The Na(2)-O(9) bond length is 2.56 Å. In the third Na site, Na(3) is bonded in a 7-coordinate geometry to one O(11), one O(2), one O(5), one O(6), one O(7), and two equivalent O(4) atoms. The Na(3)-O(11) bond length is 2.53 Å. The Na(3)-O(2) bond length is 2.79 Å. The Na(3)-O(5) bond length is 2.43 Å. The Na(3)-O(6) bond length is 2.55 Å. The Na(3)-O(7) bond length is 2.57 Å. There is one shorter (2.86 Å) and one longer (2.99 Å) Na(3)-O(4) bond length. Hf(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 HfO6 octahedra that share corners with two equivalent Ge(1)O4 tetrahedra, corners with two equivalent Ge(2)O4 tetrahedra, and corners with two equivalent Ge(3)O4 tetrahedra. The Hf(1)-O(1) bond length is 2.12 Å. The Hf(1)-O(11) bond length is 2.13 Å. The Hf(1)-O(4) bond length is 2.04 Å. The Hf(1)-O(5) bond length is 2.12 Å. The Hf(1)-O(8) bond length is 1.99 Å. The Hf(1)-O(9) bond length is 2.05 Å. Ta(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 TaO6 octahedra that share corners with two equivalent Ge(1)O4 tetrahedra, corners with two equivalent Ge(2)O4 tetrahedra, and corners with two equivalent Ge(3)O4 tetrahedra. The Ta(1)-O(10) bond length is 1.99 Å. The Ta(1)-O(12) bond length is 2.02 Å. The Ta(1)-O(2) bond length is 2.07 Å. The Ta(1)-O(3) bond length is 1.92 Å. The Ta(1)-O(6) bond length is 2.05 Å. The Ta(1)-O(7) bond length is 1.99 Å. There are three inequivalent Ge sites. In the first Ge site, Ge(1) is bonded to one O(11), one O(12), one O(3), and one O(4) atom to form GeO4 tetrahedra that share corners with two equivalent Hf(1)O6 octahedra and corners with two equivalent Ta(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 19-42°. The Ge(1)-O(11) bond length is 1.76 Å. The Ge(1)-O(12) bond length is 1.77 Å. The Ge(1)-O(3) bond length is 1.80 Å. The Ge(1)-O(4) bond length is 1.73 Å. In the second Ge site, Ge(2) is bonded to one O(2), one O(5), one O(7), and one O(9) atom to form GeO4 tetrahedra that share corners with two equivalent Hf(1)O6 octahedra and corners with two equivalent Ta(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 26-41°. The Ge(2)-O(2) bond length is 1.79 Å. The Ge(2)-O(5) bond length is 1.75 Å. The Ge(2)-O(7) bond length is 1.80 Å. The Ge(2)-O(9) bond length is 1.73 Å. In the third Ge site, Ge(3) is bonded to one O(1), one O(10), one O(6), and one O(8) atom to form GeO4 tetrahedra that share corners with two equivalent Hf(1)O6 octahedra and corners with two equivalent Ta(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 17-40°. The Ge(3)-O(1) bond length is 1.74 Å. The Ge(3)-O(10) bond length is 1.80 Å. The Ge(3)-O(6) bond length is 1.77 Å. The Ge(3)-O(8) bond length is 1.73 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 Hf(1), and one Ge(3) atom. In the second O site, O(2) is bonded in a 5-coordinate geometry to one Na(1), one Na(2), one Na(3), one Ta(1), and one Ge(2) atom. In the third O site, O(3) is bonded in a bent 150 degrees geometry to one Ta(1) and one Ge(1) atom. In the fourth O site, O(4) is bonded in a distorted bent 150 degrees geometry to two equivalent Na(3), one Hf(1), and one Ge(1) atom. In the fifth O site, O(5) is bonded in a rectangular see-saw-like geometry to one Na(1), one Na(3), one Hf(1), and one Ge(2) atom. In the sixth O site, O(6) is bonded to one Na(1), one Na(3), one Ta(1), and one Ge(3) atom to form distorted corner-sharing ONa2TaGe trigonal pyramids. In the seventh O site, O(7) is bonded in a 3-coordinate geometry to one Na(3), one Ta(1), and one Ge(2) atom. In the eighth O site, O(8) is bonded in a linear geometry to one Hf(1) and one Ge(3) atom. In the ninth O site, O(9) is bonded in a 3-coordinate geometry to one Na(2), one Hf(1), and one Ge(2) atom. In the tenth O site, O(10) is bonded in a 3-coordinate geometry to one Na(2), one Ta(1), and one Ge(3) atom. In the eleventh O site, O(11) is bonded to one Na(1), one Na(2), one Na(3), one Hf(1), and one Ge(1) atom to form distorted corner-sharing ONa3HfGe trigonal bipyramids. In the twelfth O site, O(12) is bonded in a distorted rectangular see-saw-like geometry to one Na(1), one Na(2), one Ta(1), and one Ge(1) atom.