Na2TiSi4H4O13 crystallizes in the tetragonal P42_12 space group. Na(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(5) atoms to form distorted NaO6 pentagonal pyramids that share corners with two equivalent Si(1)O4 tetrahedra, corners with two equivalent Ti(1)O5 trigonal bipyramids,  an edgeedge with one Na(1)O6 pentagonal pyramid, and edges with two equivalent Si(1)O4 tetrahedra. Ti(1) is bonded to one O(3) and four equivalent O(2) atoms to form distorted TiO5 trigonal bipyramids that share corners with four equivalent Na(1)O6 pentagonal pyramids and corners with four equivalent Si(1)O4 tetrahedra. Si(1) is bonded to one O(2), one O(4), and two equivalent O(1) atoms to form SiO4 tetrahedra that share  a cornercorner with one Na(1)O6 pentagonal pyramid, corners with three equivalent Si(1)O4 tetrahedra,  a cornercorner with one Ti(1)O5 trigonal bipyramid, and  an edgeedge with one Na(1)O6 pentagonal pyramid. H(1) is bonded in a single-bond geometry to one O(5) atom. There are five inequivalent O sites. In the first O site, O(3) is bonded in a single-bond geometry to one Ti(1) atom. In the second O site, O(4) is bonded in a linear geometry to two equivalent Si(1) atoms. In the third O site, O(5) is bonded in a distorted water-like geometry to two equivalent Na(1) and two equivalent H(1) atoms. In the fourth O site, O(1) is bonded in a 3-coordinate geometry to one Na(1) and two equivalent Si(1) atoms. In the fifth O site, O(2) is bonded in a 3-coordinate geometry to one Na(1), one Ti(1), and one Si(1) atom.
Na2TiSi4H4O13 crystallizes in the tetragonal P42_12 space group. Na(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(5) atoms to form distorted NaO6 pentagonal pyramids that share corners with two equivalent Si(1)O4 tetrahedra, corners with two equivalent Ti(1)O5 trigonal bipyramids,  an edgeedge with one Na(1)O6 pentagonal pyramid, and edges with two equivalent Si(1)O4 tetrahedra. Both Na(1)-O(1) bond lengths are 2.52 Å. Both Na(1)-O(2) bond lengths are 2.43 Å. Both Na(1)-O(5) bond lengths are 2.40 Å. Ti(1) is bonded to one O(3) and four equivalent O(2) atoms to form distorted TiO5 trigonal bipyramids that share corners with four equivalent Na(1)O6 pentagonal pyramids and corners with four equivalent Si(1)O4 tetrahedra. The Ti(1)-O(3) bond length is 1.75 Å. All Ti(1)-O(2) bond lengths are 1.96 Å. Si(1) is bonded to one O(2), one O(4), and two equivalent O(1) atoms to form SiO4 tetrahedra that share  a cornercorner with one Na(1)O6 pentagonal pyramid, corners with three equivalent Si(1)O4 tetrahedra,  a cornercorner with one Ti(1)O5 trigonal bipyramid, and  an edgeedge with one Na(1)O6 pentagonal pyramid. The Si(1)-O(2) bond length is 1.61 Å. The Si(1)-O(4) bond length is 1.62 Å. There is one shorter (1.64 Å) and one longer (1.65 Å) Si(1)-O(1) bond length. H(1) is bonded in a single-bond geometry to one O(5) atom. The H(1)-O(5) bond length is 0.99 Å. There are five inequivalent O sites. In the first O site, O(3) is bonded in a single-bond geometry to one Ti(1) atom. In the second O site, O(4) is bonded in a linear geometry to two equivalent Si(1) atoms. In the third O site, O(5) is bonded in a distorted water-like geometry to two equivalent Na(1) and two equivalent H(1) atoms. In the fourth O site, O(1) is bonded in a 3-coordinate geometry to one Na(1) and two equivalent Si(1) atoms. In the fifth O site, O(2) is bonded in a 3-coordinate geometry to one Na(1), one Ti(1), and one Si(1) atom.