Na7U5(SiO6)4 crystallizes in the triclinic P-1 space group. There are four inequivalent Na sites. In the first Na site, Na(1) is bonded to two equivalent O(11), two equivalent O(4), and two equivalent O(9) atoms to form NaO6 octahedra that share corners with two equivalent U(2)O7 pentagonal bipyramids, corners with two equivalent U(3)O7 pentagonal bipyramids, corners with two equivalent Si(1)O4 tetrahedra, and edges with two equivalent U(1)O6 octahedra. In the second Na site, Na(2) is bonded in a 7-coordinate geometry to one O(4), one O(6), one O(9), two equivalent O(11), and two equivalent O(5) atoms. In the third Na site, Na(3) is bonded in a 4-coordinate geometry to one O(1), one O(10), one O(12), one O(7), and one O(8) atom. In the fourth Na site, Na(4) is bonded in a 4-coordinate geometry to one O(1), one O(10), one O(12), and one O(7) atom. There are three inequivalent U sites. In the first U site, U(1) is bonded to two equivalent O(4), two equivalent O(5), and two equivalent O(9) atoms to form UO6 octahedra that share corners with two equivalent U(2)O7 pentagonal bipyramids, corners with two equivalent Si(1)O4 tetrahedra, corners with two equivalent Si(2)O4 tetrahedra, and edges with two equivalent Na(1)O6 octahedra. In the second U site, U(2) is bonded to one O(1), one O(10), one O(2), one O(3), one O(6), one O(8), and one O(9) atom to form distorted UO7 pentagonal bipyramids that share  a cornercorner with one Na(1)O6 octahedra,  a cornercorner with one U(1)O6 octahedra,  a cornercorner with one Si(1)O4 tetrahedra, corners with two equivalent Si(2)O4 tetrahedra, edges with two equivalent U(3)O7 pentagonal bipyramids, and  an edgeedge with one Si(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 48-61°. In the third U site, U(3) is bonded to one O(11), one O(12), one O(2), one O(3), one O(6), one O(7), and one O(8) atom to form distorted UO7 pentagonal bipyramids that share  a cornercorner with one Na(1)O6 octahedra,  a cornercorner with one Si(2)O4 tetrahedra, corners with two equivalent Si(1)O4 tetrahedra, edges with two equivalent U(2)O7 pentagonal bipyramids, and  an edgeedge with one Si(2)O4 tetrahedra. The corner-sharing octahedral tilt angles are 58°. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form SiO4 tetrahedra that share  a cornercorner with one Na(1)O6 octahedra,  a cornercorner with one U(1)O6 octahedra,  a cornercorner with one U(2)O7 pentagonal bipyramid, corners with two equivalent U(3)O7 pentagonal bipyramids, and  an edgeedge with one U(2)O7 pentagonal bipyramid. The corner-sharing octahedral tilt angles range from 43-68°. In the second Si site, Si(2) is bonded to one O(5), one O(6), one O(7), and one O(8) atom to form SiO4 tetrahedra that share  a cornercorner with one U(1)O6 octahedra,  a cornercorner with one U(3)O7 pentagonal bipyramid, corners with two equivalent U(2)O7 pentagonal bipyramids, and  an edgeedge with one U(3)O7 pentagonal bipyramid. The corner-sharing octahedral tilt angles are 50°. There are twelve inequivalent O sites. In the first O site, O(1) is bonded to one Na(3), one Na(4), one U(2), and one Si(1) atom to form distorted corner-sharing ONa2USi trigonal pyramids. In the second O site, O(2) is bonded in a 1-coordinate geometry to one U(2), one U(3), and one Si(1) atom. In the third O site, O(3) is bonded in a 3-coordinate geometry to one U(2), one U(3), and one Si(1) atom. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to one Na(1), one Na(2), one U(1), and one Si(1) atom. In the fifth O site, O(5) is bonded in a 4-coordinate geometry to two equivalent Na(2), one U(1), and one Si(2) atom. In the sixth O site, O(6) is bonded in a 4-coordinate geometry to one Na(2), one U(2), one U(3), and one Si(2) atom. In the seventh O site, O(7) is bonded to one Na(3), one Na(4), one U(3), and one Si(2) atom to form distorted corner-sharing ONa2USi trigonal pyramids. In the eighth O site, O(8) is bonded in a 4-coordinate geometry to one Na(3), one U(2), one U(3), and one Si(2) atom. In the ninth O site, O(9) is bonded in a distorted rectangular see-saw-like geometry to one Na(1), one Na(2), one U(1), and one U(2) atom. In the tenth O site, O(10) is bonded in a 3-coordinate geometry to one Na(3), one Na(4), and one U(2) atom. In the eleventh O site, O(11) is bonded in a distorted rectangular see-saw-like geometry to one Na(1), two equivalent Na(2), and one U(3) atom. In the twelfth O site, O(12) is bonded in a 3-coordinate geometry to one Na(3), one Na(4), and one U(3) atom.
Na7U5(SiO6)4 crystallizes in the triclinic P-1 space group. There are four inequivalent Na sites. In the first Na site, Na(1) is bonded to two equivalent O(11), two equivalent O(4), and two equivalent O(9) atoms to form NaO6 octahedra that share corners with two equivalent U(2)O7 pentagonal bipyramids, corners with two equivalent U(3)O7 pentagonal bipyramids, corners with two equivalent Si(1)O4 tetrahedra, and edges with two equivalent U(1)O6 octahedra. Both Na(1)-O(11) bond lengths are 2.64 Å. Both Na(1)-O(4) bond lengths are 2.35 Å. Both Na(1)-O(9) bond lengths are 2.47 Å. In the second Na site, Na(2) is bonded in a 7-coordinate geometry to one O(4), one O(6), one O(9), two equivalent O(11), and two equivalent O(5) atoms. The Na(2)-O(4) bond length is 3.00 Å. The Na(2)-O(6) bond length is 2.84 Å. The Na(2)-O(9) bond length is 2.74 Å. There is one shorter (2.40 Å) and one longer (2.56 Å) Na(2)-O(11) bond length. There is one shorter (2.53 Å) and one longer (2.64 Å) Na(2)-O(5) bond length. In the third Na site, Na(3) is bonded in a 4-coordinate geometry to one O(1), one O(10), one O(12), one O(7), and one O(8) atom. The Na(3)-O(1) bond length is 2.44 Å. The Na(3)-O(10) bond length is 2.41 Å. The Na(3)-O(12) bond length is 2.49 Å. The Na(3)-O(7) bond length is 2.49 Å. The Na(3)-O(8) bond length is 2.91 Å. In the fourth Na site, Na(4) is bonded in a 4-coordinate geometry to one O(1), one O(10), one O(12), and one O(7) atom. The Na(4)-O(1) bond length is 2.39 Å. The Na(4)-O(10) bond length is 2.32 Å. The Na(4)-O(12) bond length is 2.37 Å. The Na(4)-O(7) bond length is 2.43 Å. There are three inequivalent U sites. In the first U site, U(1) is bonded to two equivalent O(4), two equivalent O(5), and two equivalent O(9) atoms to form UO6 octahedra that share corners with two equivalent U(2)O7 pentagonal bipyramids, corners with two equivalent Si(1)O4 tetrahedra, corners with two equivalent Si(2)O4 tetrahedra, and edges with two equivalent Na(1)O6 octahedra. Both U(1)-O(4) bond lengths are 2.20 Å. Both U(1)-O(5) bond lengths are 2.26 Å. Both U(1)-O(9) bond lengths are 2.18 Å. In the second U site, U(2) is bonded to one O(1), one O(10), one O(2), one O(3), one O(6), one O(8), and one O(9) atom to form distorted UO7 pentagonal bipyramids that share  a cornercorner with one Na(1)O6 octahedra,  a cornercorner with one U(1)O6 octahedra,  a cornercorner with one Si(1)O4 tetrahedra, corners with two equivalent Si(2)O4 tetrahedra, edges with two equivalent U(3)O7 pentagonal bipyramids, and  an edgeedge with one Si(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 48-61°. The U(2)-O(1) bond length is 2.29 Å. The U(2)-O(10) bond length is 1.92 Å. The U(2)-O(2) bond length is 2.52 Å. The U(2)-O(3) bond length is 2.55 Å. The U(2)-O(6) bond length is 2.31 Å. The U(2)-O(8) bond length is 2.29 Å. The U(2)-O(9) bond length is 2.09 Å. In the third U site, U(3) is bonded to one O(11), one O(12), one O(2), one O(3), one O(6), one O(7), and one O(8) atom to form distorted UO7 pentagonal bipyramids that share  a cornercorner with one Na(1)O6 octahedra,  a cornercorner with one Si(2)O4 tetrahedra, corners with two equivalent Si(1)O4 tetrahedra, edges with two equivalent U(2)O7 pentagonal bipyramids, and  an edgeedge with one Si(2)O4 tetrahedra. The corner-sharing octahedral tilt angles are 58°. The U(3)-O(11) bond length is 1.91 Å. The U(3)-O(12) bond length is 1.91 Å. The U(3)-O(2) bond length is 2.30 Å. The U(3)-O(3) bond length is 2.30 Å. The U(3)-O(6) bond length is 2.57 Å. The U(3)-O(7) bond length is 2.31 Å. The U(3)-O(8) bond length is 2.55 Å. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form SiO4 tetrahedra that share  a cornercorner with one Na(1)O6 octahedra,  a cornercorner with one U(1)O6 octahedra,  a cornercorner with one U(2)O7 pentagonal bipyramid, corners with two equivalent U(3)O7 pentagonal bipyramids, and  an edgeedge with one U(2)O7 pentagonal bipyramid. The corner-sharing octahedral tilt angles range from 43-68°. The Si(1)-O(1) bond length is 1.63 Å. The Si(1)-O(2) bond length is 1.65 Å. The Si(1)-O(3) bond length is 1.64 Å. The Si(1)-O(4) bond length is 1.65 Å. In the second Si site, Si(2) is bonded to one O(5), one O(6), one O(7), and one O(8) atom to form SiO4 tetrahedra that share  a cornercorner with one U(1)O6 octahedra,  a cornercorner with one U(3)O7 pentagonal bipyramid, corners with two equivalent U(2)O7 pentagonal bipyramids, and  an edgeedge with one U(3)O7 pentagonal bipyramid. The corner-sharing octahedral tilt angles are 50°. The Si(2)-O(5) bond length is 1.66 Å. The Si(2)-O(6) bond length is 1.65 Å. The Si(2)-O(7) bond length is 1.62 Å. The Si(2)-O(8) bond length is 1.66 Å. There are twelve inequivalent O sites. In the first O site, O(1) is bonded to one Na(3), one Na(4), one U(2), and one Si(1) atom to form distorted corner-sharing ONa2USi trigonal pyramids. In the second O site, O(2) is bonded in a 1-coordinate geometry to one U(2), one U(3), and one Si(1) atom. In the third O site, O(3) is bonded in a 3-coordinate geometry to one U(2), one U(3), and one Si(1) atom. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to one Na(1), one Na(2), one U(1), and one Si(1) atom. In the fifth O site, O(5) is bonded in a 4-coordinate geometry to two equivalent Na(2), one U(1), and one Si(2) atom. In the sixth O site, O(6) is bonded in a 4-coordinate geometry to one Na(2), one U(2), one U(3), and one Si(2) atom. In the seventh O site, O(7) is bonded to one Na(3), one Na(4), one U(3), and one Si(2) atom to form distorted corner-sharing ONa2USi trigonal pyramids. In the eighth O site, O(8) is bonded in a 4-coordinate geometry to one Na(3), one U(2), one U(3), and one Si(2) atom. In the ninth O site, O(9) is bonded in a distorted rectangular see-saw-like geometry to one Na(1), one Na(2), one U(1), and one U(2) atom. In the tenth O site, O(10) is bonded in a 3-coordinate geometry to one Na(3), one Na(4), and one U(2) atom. In the eleventh O site, O(11) is bonded in a distorted rectangular see-saw-like geometry to one Na(1), two equivalent Na(2), and one U(3) atom. In the twelfth O site, O(12) is bonded in a 3-coordinate geometry to one Na(3), one Na(4), and one U(3) atom.