NaLiSi2H4O7 crystallizes in the monoclinic C2/c space group. Na(1) is bonded to two equivalent O(1) and four equivalent O(4) atoms to form distorted NaO6 octahedra that share corners with two equivalent Li(1)O4 tetrahedra, corners with two equivalent Si(1)O4 tetrahedra, edges with two equivalent Na(1)O6 octahedra, and  an edgeedge with one Li(1)O4 tetrahedra. Li(1) is bonded to four equivalent O(1) atoms to form LiO4 tetrahedra that share corners with two equivalent Na(1)O6 octahedra, corners with four equivalent Si(1)O4 tetrahedra,  an edgeedge with one Na(1)O6 octahedra, and edges with two equivalent Li(1)O4 tetrahedra. The corner-sharing octahedral tilt angles are 63°. Si(1) is bonded to one O(1), one O(3), and two equivalent O(2) atoms to form SiO4 tetrahedra that share  a cornercorner with one Na(1)O6 octahedra, corners with two equivalent Li(1)O4 tetrahedra, and corners with three equivalent Si(1)O4 tetrahedra. The corner-sharing octahedral tilt angles are 55°. There are two inequivalent H sites. In the first H site, H(1) is bonded in a single-bond geometry to one O(4) atom. In the second H site, H(2) is bonded in a single-bond geometry to one O(4) atom. There are four inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to one Na(1), two equivalent Li(1), and one Si(1) atom. In the second O site, O(2) is bonded in a bent 120 degrees geometry to two equivalent Si(1) atoms. In the third O site, O(3) is bonded in a linear geometry to two equivalent Si(1) atoms. In the fourth O site, O(4) is bonded in a distorted water-like geometry to two equivalent Na(1), one H(1), and one H(2) atom.
NaLiSi2H4O7 crystallizes in the monoclinic C2/c space group. Na(1) is bonded to two equivalent O(1) and four equivalent O(4) atoms to form distorted NaO6 octahedra that share corners with two equivalent Li(1)O4 tetrahedra, corners with two equivalent Si(1)O4 tetrahedra, edges with two equivalent Na(1)O6 octahedra, and  an edgeedge with one Li(1)O4 tetrahedra. Both Na(1)-O(1) bond lengths are 2.51 Å. There are two shorter (2.33 Å) and two longer (2.56 Å) Na(1)-O(4) bond lengths. Li(1) is bonded to four equivalent O(1) atoms to form LiO4 tetrahedra that share corners with two equivalent Na(1)O6 octahedra, corners with four equivalent Si(1)O4 tetrahedra,  an edgeedge with one Na(1)O6 octahedra, and edges with two equivalent Li(1)O4 tetrahedra. The corner-sharing octahedral tilt angles are 63°. All Li(1)-O(1) bond lengths are 2.02 Å. Si(1) is bonded to one O(1), one O(3), and two equivalent O(2) atoms to form SiO4 tetrahedra that share  a cornercorner with one Na(1)O6 octahedra, corners with two equivalent Li(1)O4 tetrahedra, and corners with three equivalent Si(1)O4 tetrahedra. The corner-sharing octahedral tilt angles are 55°. The Si(1)-O(1) bond length is 1.61 Å. The Si(1)-O(3) bond length is 1.62 Å. Both Si(1)-O(2) bond lengths are 1.66 Å. There are two inequivalent H sites. In the first H site, H(1) is bonded in a single-bond geometry to one O(4) atom. The H(1)-O(4) bond length is 0.98 Å. In the second H site, H(2) is bonded in a single-bond geometry to one O(4) atom. The H(2)-O(4) bond length is 0.99 Å. There are four inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to one Na(1), two equivalent Li(1), and one Si(1) atom. In the second O site, O(2) is bonded in a bent 120 degrees geometry to two equivalent Si(1) atoms. In the third O site, O(3) is bonded in a linear geometry to two equivalent Si(1) atoms. In the fourth O site, O(4) is bonded in a distorted water-like geometry to two equivalent Na(1), one H(1), and one H(2) atom.