Na4TeO5 is Caswellsilverite-like structured and crystallizes in the triclinic P-1 space group. There are five inequivalent Na sites. In the first Na site, Na(1) is bonded to one O(3), one O(5), two equivalent O(1), and two equivalent O(4) atoms to form distorted NaO6 octahedra that share  a cornercorner with one Na(5)O6 octahedra, corners with two equivalent Te(1)O6 octahedra, corners with three equivalent Na(3)O6 octahedra,  an edgeedge with one Na(3)O6 octahedra,  an edgeedge with one Na(4)O6 octahedra, edges with two equivalent Na(1)O6 octahedra, edges with two equivalent Na(5)O6 octahedra, edges with three equivalent Na(2)O6 octahedra, and edges with three equivalent Te(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 3-22°. In the second Na site, Na(2) is bonded to one O(1), one O(3), one O(4), one O(5), and two equivalent O(2) atoms to form distorted NaO6 octahedra that share  a cornercorner with one Na(5)O6 octahedra, corners with two equivalent Na(3)O6 octahedra, corners with three equivalent Te(1)O6 octahedra,  an edgeedge with one Na(2)O6 octahedra,  an edgeedge with one Na(5)O6 octahedra, edges with two equivalent Na(4)O6 octahedra, edges with two equivalent Te(1)O6 octahedra, edges with three equivalent Na(1)O6 octahedra, and edges with three equivalent Na(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 3-21°. In the third Na site, Na(3) is bonded to one O(1), one O(3), two equivalent O(2), and two equivalent O(5) atoms to form distorted NaO6 octahedra that share  a cornercorner with one Na(4)O6 octahedra, corners with two equivalent Na(2)O6 octahedra, corners with three equivalent Na(1)O6 octahedra,  an edgeedge with one Na(1)O6 octahedra,  an edgeedge with one Na(5)O6 octahedra, edges with two equivalent Na(3)O6 octahedra, edges with two equivalent Na(4)O6 octahedra, edges with three equivalent Na(2)O6 octahedra, and edges with three equivalent Te(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 18-22°. In the fourth Na site, Na(4) is bonded to two equivalent O(2), two equivalent O(3), and two equivalent O(5) atoms to form distorted NaO6 octahedra that share corners with two equivalent Na(3)O6 octahedra, corners with two equivalent Na(5)O6 octahedra, corners with two equivalent Te(1)O6 octahedra, edges with two equivalent Na(1)O6 octahedra, edges with two equivalent Te(1)O6 octahedra, edges with four equivalent Na(2)O6 octahedra, and edges with four equivalent Na(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 4-19°. In the fifth Na site, Na(5) is bonded to two equivalent O(1), two equivalent O(3), and two equivalent O(4) atoms to form distorted NaO6 octahedra that share corners with two equivalent Na(1)O6 octahedra, corners with two equivalent Na(2)O6 octahedra, corners with two equivalent Na(4)O6 octahedra, edges with two equivalent Na(2)O6 octahedra, edges with two equivalent Na(3)O6 octahedra, edges with four equivalent Na(1)O6 octahedra, and edges with four equivalent Te(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 17-20°. Te(1) is bonded to one O(1), one O(2), one O(3), one O(5), and two equivalent O(4) atoms to form TeO6 octahedra that share  a cornercorner with one Na(4)O6 octahedra, corners with two equivalent Na(1)O6 octahedra, corners with three equivalent Na(2)O6 octahedra,  an edgeedge with one Na(4)O6 octahedra,  an edgeedge with one Te(1)O6 octahedra, edges with two equivalent Na(2)O6 octahedra, edges with two equivalent Na(5)O6 octahedra, edges with three equivalent Na(1)O6 octahedra, and edges with three equivalent Na(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 3-15°. There are five inequivalent O sites. In the first O site, O(1) is bonded to one Na(2), one Na(3), one Na(5), two equivalent Na(1), and one Te(1) atom to form distorted ONa5Te octahedra that share  a cornercorner with one O(4)Na4Te2 octahedra,  a cornercorner with one O(1)Na5Te octahedra,  a cornercorner with one O(2)Na5Te octahedra,  a cornercorner with one O(3)Na5Te octahedra,  an edgeedge with one O(1)Na5Te octahedra, edges with two equivalent O(2)Na5Te octahedra, edges with three equivalent O(3)Na5Te octahedra, and edges with four equivalent O(4)Na4Te2 octahedra. The corner-sharing octahedral tilt angles range from 0-18°. In the second O site, O(2) is bonded to one Na(4), two equivalent Na(2), two equivalent Na(3), and one Te(1) atom to form distorted ONa5Te octahedra that share  a cornercorner with one O(1)Na5Te octahedra,  a cornercorner with one O(2)Na5Te octahedra,  a cornercorner with one O(3)Na5Te octahedra, corners with two equivalent O(4)Na4Te2 octahedra,  an edgeedge with one O(4)Na4Te2 octahedra, edges with two equivalent O(1)Na5Te octahedra, edges with two equivalent O(2)Na5Te octahedra, and edges with three equivalent O(3)Na5Te octahedra. The corner-sharing octahedral tilt angles range from 0-18°. In the third O site, O(3) is bonded to one Na(1), one Na(2), one Na(3), one Na(4), one Na(5), and one Te(1) atom to form distorted ONa5Te octahedra that share  a cornercorner with one O(4)Na4Te2 octahedra,  a cornercorner with one O(1)Na5Te octahedra,  a cornercorner with one O(2)Na5Te octahedra, corners with two equivalent O(3)Na5Te octahedra, edges with three equivalent O(4)Na4Te2 octahedra, edges with three equivalent O(1)Na5Te octahedra, and edges with three equivalent O(2)Na5Te octahedra. The corner-sharing octahedral tilt angles range from 0-14°. In the fourth O site, O(4) is bonded to one Na(2), one Na(5), two equivalent Na(1), and two equivalent Te(1) atoms to form distorted ONa4Te2 octahedra that share  a cornercorner with one O(4)Na4Te2 octahedra,  a cornercorner with one O(1)Na5Te octahedra,  a cornercorner with one O(3)Na5Te octahedra, corners with two equivalent O(2)Na5Te octahedra,  an edgeedge with one O(2)Na5Te octahedra, edges with two equivalent O(4)Na4Te2 octahedra, edges with three equivalent O(3)Na5Te octahedra, and edges with four equivalent O(1)Na5Te octahedra. The corner-sharing octahedral tilt angles range from 0-14°. In the fifth O site, O(5) is bonded in a 6-coordinate geometry to one Na(1), one Na(2), one Na(4), two equivalent Na(3), and one Te(1) atom.
Na4TeO5 is Caswellsilverite-like structured and crystallizes in the triclinic P-1 space group. There are five inequivalent Na sites. In the first Na site, Na(1) is bonded to one O(3), one O(5), two equivalent O(1), and two equivalent O(4) atoms to form distorted NaO6 octahedra that share  a cornercorner with one Na(5)O6 octahedra, corners with two equivalent Te(1)O6 octahedra, corners with three equivalent Na(3)O6 octahedra,  an edgeedge with one Na(3)O6 octahedra,  an edgeedge with one Na(4)O6 octahedra, edges with two equivalent Na(1)O6 octahedra, edges with two equivalent Na(5)O6 octahedra, edges with three equivalent Na(2)O6 octahedra, and edges with three equivalent Te(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 3-22°. The Na(1)-O(3) bond length is 2.34 Å. The Na(1)-O(5) bond length is 2.29 Å. There is one shorter (2.33 Å) and one longer (2.48 Å) Na(1)-O(1) bond length. There is one shorter (2.37 Å) and one longer (2.55 Å) Na(1)-O(4) bond length. In the second Na site, Na(2) is bonded to one O(1), one O(3), one O(4), one O(5), and two equivalent O(2) atoms to form distorted NaO6 octahedra that share  a cornercorner with one Na(5)O6 octahedra, corners with two equivalent Na(3)O6 octahedra, corners with three equivalent Te(1)O6 octahedra,  an edgeedge with one Na(2)O6 octahedra,  an edgeedge with one Na(5)O6 octahedra, edges with two equivalent Na(4)O6 octahedra, edges with two equivalent Te(1)O6 octahedra, edges with three equivalent Na(1)O6 octahedra, and edges with three equivalent Na(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 3-21°. The Na(2)-O(1) bond length is 2.33 Å. The Na(2)-O(3) bond length is 2.50 Å. The Na(2)-O(4) bond length is 2.68 Å. The Na(2)-O(5) bond length is 2.34 Å. There is one shorter (2.30 Å) and one longer (2.58 Å) Na(2)-O(2) bond length. In the third Na site, Na(3) is bonded to one O(1), one O(3), two equivalent O(2), and two equivalent O(5) atoms to form distorted NaO6 octahedra that share  a cornercorner with one Na(4)O6 octahedra, corners with two equivalent Na(2)O6 octahedra, corners with three equivalent Na(1)O6 octahedra,  an edgeedge with one Na(1)O6 octahedra,  an edgeedge with one Na(5)O6 octahedra, edges with two equivalent Na(3)O6 octahedra, edges with two equivalent Na(4)O6 octahedra, edges with three equivalent Na(2)O6 octahedra, and edges with three equivalent Te(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 18-22°. The Na(3)-O(1) bond length is 2.37 Å. The Na(3)-O(3) bond length is 2.41 Å. There is one shorter (2.30 Å) and one longer (2.48 Å) Na(3)-O(2) bond length. There is one shorter (2.31 Å) and one longer (2.37 Å) Na(3)-O(5) bond length. In the fourth Na site, Na(4) is bonded to two equivalent O(2), two equivalent O(3), and two equivalent O(5) atoms to form distorted NaO6 octahedra that share corners with two equivalent Na(3)O6 octahedra, corners with two equivalent Na(5)O6 octahedra, corners with two equivalent Te(1)O6 octahedra, edges with two equivalent Na(1)O6 octahedra, edges with two equivalent Te(1)O6 octahedra, edges with four equivalent Na(2)O6 octahedra, and edges with four equivalent Na(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 4-19°. Both Na(4)-O(2) bond lengths are 2.27 Å. Both Na(4)-O(3) bond lengths are 2.30 Å. Both Na(4)-O(5) bond lengths are 2.78 Å. In the fifth Na site, Na(5) is bonded to two equivalent O(1), two equivalent O(3), and two equivalent O(4) atoms to form distorted NaO6 octahedra that share corners with two equivalent Na(1)O6 octahedra, corners with two equivalent Na(2)O6 octahedra, corners with two equivalent Na(4)O6 octahedra, edges with two equivalent Na(2)O6 octahedra, edges with two equivalent Na(3)O6 octahedra, edges with four equivalent Na(1)O6 octahedra, and edges with four equivalent Te(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 17-20°. Both Na(5)-O(1) bond lengths are 2.34 Å. Both Na(5)-O(3) bond lengths are 2.35 Å. Both Na(5)-O(4) bond lengths are 2.30 Å. Te(1) is bonded to one O(1), one O(2), one O(3), one O(5), and two equivalent O(4) atoms to form TeO6 octahedra that share  a cornercorner with one Na(4)O6 octahedra, corners with two equivalent Na(1)O6 octahedra, corners with three equivalent Na(2)O6 octahedra,  an edgeedge with one Na(4)O6 octahedra,  an edgeedge with one Te(1)O6 octahedra, edges with two equivalent Na(2)O6 octahedra, edges with two equivalent Na(5)O6 octahedra, edges with three equivalent Na(1)O6 octahedra, and edges with three equivalent Na(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 3-15°. The Te(1)-O(1) bond length is 1.92 Å. The Te(1)-O(2) bond length is 1.91 Å. The Te(1)-O(3) bond length is 1.92 Å. The Te(1)-O(5) bond length is 1.90 Å. There is one shorter (2.06 Å) and one longer (2.08 Å) Te(1)-O(4) bond length. There are five inequivalent O sites. In the first O site, O(1) is bonded to one Na(2), one Na(3), one Na(5), two equivalent Na(1), and one Te(1) atom to form distorted ONa5Te octahedra that share  a cornercorner with one O(4)Na4Te2 octahedra,  a cornercorner with one O(1)Na5Te octahedra,  a cornercorner with one O(2)Na5Te octahedra,  a cornercorner with one O(3)Na5Te octahedra,  an edgeedge with one O(1)Na5Te octahedra, edges with two equivalent O(2)Na5Te octahedra, edges with three equivalent O(3)Na5Te octahedra, and edges with four equivalent O(4)Na4Te2 octahedra. The corner-sharing octahedral tilt angles range from 0-18°. In the second O site, O(2) is bonded to one Na(4), two equivalent Na(2), two equivalent Na(3), and one Te(1) atom to form distorted ONa5Te octahedra that share  a cornercorner with one O(1)Na5Te octahedra,  a cornercorner with one O(2)Na5Te octahedra,  a cornercorner with one O(3)Na5Te octahedra, corners with two equivalent O(4)Na4Te2 octahedra,  an edgeedge with one O(4)Na4Te2 octahedra, edges with two equivalent O(1)Na5Te octahedra, edges with two equivalent O(2)Na5Te octahedra, and edges with three equivalent O(3)Na5Te octahedra. The corner-sharing octahedral tilt angles range from 0-18°. In the third O site, O(3) is bonded to one Na(1), one Na(2), one Na(3), one Na(4), one Na(5), and one Te(1) atom to form distorted ONa5Te octahedra that share  a cornercorner with one O(4)Na4Te2 octahedra,  a cornercorner with one O(1)Na5Te octahedra,  a cornercorner with one O(2)Na5Te octahedra, corners with two equivalent O(3)Na5Te octahedra, edges with three equivalent O(4)Na4Te2 octahedra, edges with three equivalent O(1)Na5Te octahedra, and edges with three equivalent O(2)Na5Te octahedra. The corner-sharing octahedral tilt angles range from 0-14°. In the fourth O site, O(4) is bonded to one Na(2), one Na(5), two equivalent Na(1), and two equivalent Te(1) atoms to form distorted ONa4Te2 octahedra that share  a cornercorner with one O(4)Na4Te2 octahedra,  a cornercorner with one O(1)Na5Te octahedra,  a cornercorner with one O(3)Na5Te octahedra, corners with two equivalent O(2)Na5Te octahedra,  an edgeedge with one O(2)Na5Te octahedra, edges with two equivalent O(4)Na4Te2 octahedra, edges with three equivalent O(3)Na5Te octahedra, and edges with four equivalent O(1)Na5Te octahedra. The corner-sharing octahedral tilt angles range from 0-14°. In the fifth O site, O(5) is bonded in a 6-coordinate geometry to one Na(1), one Na(2), one Na(4), two equivalent Na(3), and one Te(1) atom.