KNaS2O7 crystallizes in the triclinic P-1 space group. K(1) is bonded in a 9-coordinate geometry to one O(2), one O(3), one O(4), one O(7), two equivalent O(5), and three equivalent O(6) atoms. Na(1) is bonded to one O(2), one O(4), one O(5), one O(7), and two equivalent O(3) atoms to form distorted NaO6 octahedra that share corners with two equivalent S(1)O4 tetrahedra, corners with four equivalent S(2)O4 tetrahedra, and  an edgeedge with one Na(1)O6 octahedra. There are two inequivalent S sites. In the first S site, S(1) is bonded to one O(1), one O(4), one O(5), and one O(6) atom to form SO4 tetrahedra that share corners with two equivalent Na(1)O6 octahedra and  a cornercorner with one S(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 48-52°. In the second S site, S(2) is bonded to one O(1), one O(2), one O(3), and one O(7) atom to form SO4 tetrahedra that share corners with four equivalent Na(1)O6 octahedra and  a cornercorner with one S(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 49-61°. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a bent 120 degrees geometry to one S(1) and one S(2) atom. In the second O site, O(2) is bonded in a 3-coordinate geometry to one K(1), one Na(1), and one S(2) atom. In the third O site, O(3) is bonded in a 4-coordinate geometry to one K(1), two equivalent Na(1), and one S(2) atom. In the fourth O site, O(4) is bonded in a 2-coordinate geometry to one K(1), one Na(1), and one S(1) atom. In the fifth O site, O(5) is bonded in a 4-coordinate geometry to two equivalent K(1), one Na(1), and one S(1) atom. In the sixth O site, O(6) is bonded in a distorted single-bond geometry to three equivalent K(1) and one S(1) atom. In the seventh O site, O(7) is bonded in a distorted single-bond geometry to one K(1), one Na(1), and one S(2) atom.
KNaS2O7 crystallizes in the triclinic P-1 space group. K(1) is bonded in a 9-coordinate geometry to one O(2), one O(3), one O(4), one O(7), two equivalent O(5), and three equivalent O(6) atoms. The K(1)-O(2) bond length is 2.91 Å. The K(1)-O(3) bond length is 3.07 Å. The K(1)-O(4) bond length is 3.00 Å. The K(1)-O(7) bond length is 2.88 Å. There is one shorter (2.83 Å) and one longer (3.15 Å) K(1)-O(5) bond length. There are a spread of K(1)-O(6) bond distances ranging from 2.73-3.23 Å. Na(1) is bonded to one O(2), one O(4), one O(5), one O(7), and two equivalent O(3) atoms to form distorted NaO6 octahedra that share corners with two equivalent S(1)O4 tetrahedra, corners with four equivalent S(2)O4 tetrahedra, and  an edgeedge with one Na(1)O6 octahedra. The Na(1)-O(2) bond length is 2.35 Å. The Na(1)-O(4) bond length is 2.32 Å. The Na(1)-O(5) bond length is 2.36 Å. The Na(1)-O(7) bond length is 2.78 Å. There is one shorter (2.44 Å) and one longer (2.55 Å) Na(1)-O(3) bond length. There are two inequivalent S sites. In the first S site, S(1) is bonded to one O(1), one O(4), one O(5), and one O(6) atom to form SO4 tetrahedra that share corners with two equivalent Na(1)O6 octahedra and  a cornercorner with one S(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 48-52°. The S(1)-O(1) bond length is 1.66 Å. The S(1)-O(4) bond length is 1.46 Å. The S(1)-O(5) bond length is 1.47 Å. The S(1)-O(6) bond length is 1.45 Å. In the second S site, S(2) is bonded to one O(1), one O(2), one O(3), and one O(7) atom to form SO4 tetrahedra that share corners with four equivalent Na(1)O6 octahedra and  a cornercorner with one S(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 49-61°. The S(2)-O(1) bond length is 1.68 Å. The S(2)-O(2) bond length is 1.46 Å. The S(2)-O(3) bond length is 1.47 Å. The S(2)-O(7) bond length is 1.45 Å. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a bent 120 degrees geometry to one S(1) and one S(2) atom. In the second O site, O(2) is bonded in a 3-coordinate geometry to one K(1), one Na(1), and one S(2) atom. In the third O site, O(3) is bonded in a 4-coordinate geometry to one K(1), two equivalent Na(1), and one S(2) atom. In the fourth O site, O(4) is bonded in a 2-coordinate geometry to one K(1), one Na(1), and one S(1) atom. In the fifth O site, O(5) is bonded in a 4-coordinate geometry to two equivalent K(1), one Na(1), and one S(1) atom. In the sixth O site, O(6) is bonded in a distorted single-bond geometry to three equivalent K(1) and one S(1) atom. In the seventh O site, O(7) is bonded in a distorted single-bond geometry to one K(1), one Na(1), and one S(2) atom.