Na2ZnSi2O6 crystallizes in the triclinic P1 space group. There are four inequivalent Na sites. In the first Na site, Na(1) is bonded in a 5-coordinate geometry to one O(11), one O(2), one O(5), one O(8), and one O(9) atom. In the second Na site, Na(2) is bonded to one O(1), one O(10), one O(12), one O(6), and one O(7) atom to form distorted NaO5 trigonal bipyramids that share  a cornercorner with one Zn(2)O4 tetrahedra,  a cornercorner with one Si(1)O4 tetrahedra,  a cornercorner with one Si(3)O4 tetrahedra, corners with two equivalent Zn(1)O4 tetrahedra, corners with three equivalent Si(2)O4 tetrahedra, and  an edgeedge with one Si(3)O4 tetrahedra. In the third Na site, Na(3) is bonded in a 5-coordinate geometry to one O(10), one O(12), one O(4), one O(6), and one O(7) atom. In the fourth Na site, Na(4) is bonded in a 5-coordinate geometry to one O(11), one O(3), one O(5), one O(8), and one O(9) atom. There are two inequivalent Zn sites. In the first Zn site, Zn(1) is bonded to one O(1), one O(10), one O(2), and one O(9) atom to form ZnO4 tetrahedra that share corners with two equivalent Si(1)O4 tetrahedra, corners with two equivalent Si(2)O4 tetrahedra, and corners with two equivalent Na(2)O5 trigonal bipyramids. In the second Zn site, Zn(2) is bonded to one O(11), one O(12), one O(3), and one O(4) atom to form ZnO4 tetrahedra that share corners with two equivalent Si(3)O4 tetrahedra, corners with two equivalent Si(4)O4 tetrahedra, and  a cornercorner with one Na(2)O5 trigonal bipyramid. There are four inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(1), one O(5), one O(8), and one O(9) atom to form SiO4 tetrahedra that share corners with two equivalent Zn(1)O4 tetrahedra, corners with two equivalent Si(4)O4 tetrahedra, and  a cornercorner with one Na(2)O5 trigonal bipyramid. In the second Si site, Si(2) is bonded to one O(10), one O(2), one O(6), and one O(7) atom to form SiO4 tetrahedra that share corners with two equivalent Zn(1)O4 tetrahedra, corners with two equivalent Si(3)O4 tetrahedra, and corners with three equivalent Na(2)O5 trigonal bipyramids. In the third Si site, Si(3) is bonded to one O(12), one O(3), one O(6), and one O(7) atom to form SiO4 tetrahedra that share corners with two equivalent Zn(2)O4 tetrahedra, corners with two equivalent Si(2)O4 tetrahedra,  a cornercorner with one Na(2)O5 trigonal bipyramid, and  an edgeedge with one Na(2)O5 trigonal bipyramid. In the fourth Si site, Si(4) is bonded to one O(11), one O(4), one O(5), and one O(8) atom to form SiO4 tetrahedra that share corners with two equivalent Zn(2)O4 tetrahedra and corners with two equivalent Si(1)O4 tetrahedra. There are twelve inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal planar geometry to one Na(2), one Zn(1), and one Si(1) atom. In the second O site, O(2) is bonded in a 3-coordinate geometry to one Na(1), one Zn(1), and one Si(2) atom. In the third O site, O(3) is bonded in a 3-coordinate geometry to one Na(4), one Zn(2), and one Si(3) atom. In the fourth O site, O(4) is bonded in a distorted trigonal planar geometry to one Na(3), one Zn(2), and one Si(4) atom. In the fifth O site, O(5) is bonded in a 4-coordinate geometry to one Na(1), one Na(4), one Si(1), and one Si(4) atom. In the sixth O site, O(6) is bonded in a 4-coordinate geometry to one Na(2), one Na(3), one Si(2), and one Si(3) atom. In the seventh O site, O(7) is bonded in a 4-coordinate geometry to one Na(2), one Na(3), one Si(2), and one Si(3) atom. In the eighth O site, O(8) is bonded in a 4-coordinate geometry to one Na(1), one Na(4), one Si(1), and one Si(4) atom. In the ninth O site, O(9) is bonded to one Na(1), one Na(4), one Zn(1), and one Si(1) atom to form distorted corner-sharing ONa2ZnSi trigonal pyramids. In the tenth O site, O(10) is bonded to one Na(2), one Na(3), one Zn(1), and one Si(2) atom to form distorted corner-sharing ONa2ZnSi trigonal pyramids. In the eleventh O site, O(11) is bonded to one Na(1), one Na(4), one Zn(2), and one Si(4) atom to form distorted corner-sharing ONa2ZnSi trigonal pyramids. In the twelfth O site, O(12) is bonded to one Na(2), one Na(3), one Zn(2), and one Si(3) atom to form distorted corner-sharing ONa2ZnSi trigonal pyramids.
Na2ZnSi2O6 crystallizes in the triclinic P1 space group. There are four inequivalent Na sites. In the first Na site, Na(1) is bonded in a 5-coordinate geometry to one O(11), one O(2), one O(5), one O(8), and one O(9) atom. The Na(1)-O(11) bond length is 2.37 Å. The Na(1)-O(2) bond length is 2.29 Å. The Na(1)-O(5) bond length is 2.65 Å. The Na(1)-O(8) bond length is 2.51 Å. The Na(1)-O(9) bond length is 2.31 Å. In the second Na site, Na(2) is bonded to one O(1), one O(10), one O(12), one O(6), and one O(7) atom to form distorted NaO5 trigonal bipyramids that share  a cornercorner with one Zn(2)O4 tetrahedra,  a cornercorner with one Si(1)O4 tetrahedra,  a cornercorner with one Si(3)O4 tetrahedra, corners with two equivalent Zn(1)O4 tetrahedra, corners with three equivalent Si(2)O4 tetrahedra, and  an edgeedge with one Si(3)O4 tetrahedra. The Na(2)-O(1) bond length is 2.31 Å. The Na(2)-O(10) bond length is 2.37 Å. The Na(2)-O(12) bond length is 2.41 Å. The Na(2)-O(6) bond length is 2.59 Å. The Na(2)-O(7) bond length is 2.46 Å. In the third Na site, Na(3) is bonded in a 5-coordinate geometry to one O(10), one O(12), one O(4), one O(6), and one O(7) atom. The Na(3)-O(10) bond length is 2.37 Å. The Na(3)-O(12) bond length is 2.37 Å. The Na(3)-O(4) bond length is 2.26 Å. The Na(3)-O(6) bond length is 2.55 Å. The Na(3)-O(7) bond length is 2.65 Å. In the fourth Na site, Na(4) is bonded in a 5-coordinate geometry to one O(11), one O(3), one O(5), one O(8), and one O(9) atom. The Na(4)-O(11) bond length is 2.40 Å. The Na(4)-O(3) bond length is 2.28 Å. The Na(4)-O(5) bond length is 2.54 Å. The Na(4)-O(8) bond length is 2.66 Å. The Na(4)-O(9) bond length is 2.35 Å. There are two inequivalent Zn sites. In the first Zn site, Zn(1) is bonded to one O(1), one O(10), one O(2), and one O(9) atom to form ZnO4 tetrahedra that share corners with two equivalent Si(1)O4 tetrahedra, corners with two equivalent Si(2)O4 tetrahedra, and corners with two equivalent Na(2)O5 trigonal bipyramids. The Zn(1)-O(1) bond length is 1.94 Å. The Zn(1)-O(10) bond length is 2.01 Å. The Zn(1)-O(2) bond length is 2.04 Å. The Zn(1)-O(9) bond length is 2.00 Å. In the second Zn site, Zn(2) is bonded to one O(11), one O(12), one O(3), and one O(4) atom to form ZnO4 tetrahedra that share corners with two equivalent Si(3)O4 tetrahedra, corners with two equivalent Si(4)O4 tetrahedra, and  a cornercorner with one Na(2)O5 trigonal bipyramid. The Zn(2)-O(11) bond length is 1.97 Å. The Zn(2)-O(12) bond length is 2.00 Å. The Zn(2)-O(3) bond length is 1.97 Å. The Zn(2)-O(4) bond length is 2.01 Å. There are four inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(1), one O(5), one O(8), and one O(9) atom to form SiO4 tetrahedra that share corners with two equivalent Zn(1)O4 tetrahedra, corners with two equivalent Si(4)O4 tetrahedra, and  a cornercorner with one Na(2)O5 trigonal bipyramid. The Si(1)-O(1) bond length is 1.63 Å. The Si(1)-O(5) bond length is 1.70 Å. The Si(1)-O(8) bond length is 1.68 Å. The Si(1)-O(9) bond length is 1.69 Å. In the second Si site, Si(2) is bonded to one O(10), one O(2), one O(6), and one O(7) atom to form SiO4 tetrahedra that share corners with two equivalent Zn(1)O4 tetrahedra, corners with two equivalent Si(3)O4 tetrahedra, and corners with three equivalent Na(2)O5 trigonal bipyramids. The Si(2)-O(10) bond length is 1.62 Å. The Si(2)-O(2) bond length is 1.61 Å. The Si(2)-O(6) bond length is 1.70 Å. The Si(2)-O(7) bond length is 1.71 Å. In the third Si site, Si(3) is bonded to one O(12), one O(3), one O(6), and one O(7) atom to form SiO4 tetrahedra that share corners with two equivalent Zn(2)O4 tetrahedra, corners with two equivalent Si(2)O4 tetrahedra,  a cornercorner with one Na(2)O5 trigonal bipyramid, and  an edgeedge with one Na(2)O5 trigonal bipyramid. The Si(3)-O(12) bond length is 1.66 Å. The Si(3)-O(3) bond length is 1.61 Å. The Si(3)-O(6) bond length is 1.62 Å. The Si(3)-O(7) bond length is 1.59 Å. In the fourth Si site, Si(4) is bonded to one O(11), one O(4), one O(5), and one O(8) atom to form SiO4 tetrahedra that share corners with two equivalent Zn(2)O4 tetrahedra and corners with two equivalent Si(1)O4 tetrahedra. The Si(4)-O(11) bond length is 1.57 Å. The Si(4)-O(4) bond length is 1.60 Å. The Si(4)-O(5) bond length is 1.66 Å. The Si(4)-O(8) bond length is 1.61 Å. There are twelve inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal planar geometry to one Na(2), one Zn(1), and one Si(1) atom. In the second O site, O(2) is bonded in a 3-coordinate geometry to one Na(1), one Zn(1), and one Si(2) atom. In the third O site, O(3) is bonded in a 3-coordinate geometry to one Na(4), one Zn(2), and one Si(3) atom. In the fourth O site, O(4) is bonded in a distorted trigonal planar geometry to one Na(3), one Zn(2), and one Si(4) atom. In the fifth O site, O(5) is bonded in a 4-coordinate geometry to one Na(1), one Na(4), one Si(1), and one Si(4) atom. In the sixth O site, O(6) is bonded in a 4-coordinate geometry to one Na(2), one Na(3), one Si(2), and one Si(3) atom. In the seventh O site, O(7) is bonded in a 4-coordinate geometry to one Na(2), one Na(3), one Si(2), and one Si(3) atom. In the eighth O site, O(8) is bonded in a 4-coordinate geometry to one Na(1), one Na(4), one Si(1), and one Si(4) atom. In the ninth O site, O(9) is bonded to one Na(1), one Na(4), one Zn(1), and one Si(1) atom to form distorted corner-sharing ONa2ZnSi trigonal pyramids. In the tenth O site, O(10) is bonded to one Na(2), one Na(3), one Zn(1), and one Si(2) atom to form distorted corner-sharing ONa2ZnSi trigonal pyramids. In the eleventh O site, O(11) is bonded to one Na(1), one Na(4), one Zn(2), and one Si(4) atom to form distorted corner-sharing ONa2ZnSi trigonal pyramids. In the twelfth O site, O(12) is bonded to one Na(2), one Na(3), one Zn(2), and one Si(3) atom to form distorted corner-sharing ONa2ZnSi trigonal pyramids.