Na2TiSiO5 crystallizes in the tetragonal P4/nmm space group. Na(1) is bonded to two equivalent O(1) and four equivalent O(2) atoms to form NaO6 octahedra that share corners with two equivalent Na(1)O6 octahedra, corners with four equivalent Si(1)O4 tetrahedra, corners with two equivalent Ti(1)O5 trigonal bipyramids, edges with four equivalent Na(1)O6 octahedra, and edges with two equivalent Ti(1)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles are 53°. Ti(1) is bonded to one O(1) and four equivalent O(2) atoms to form distorted TiO5 trigonal bipyramids that share corners with four equivalent Na(1)O6 octahedra, corners with four equivalent Si(1)O4 tetrahedra, and edges with four equivalent Na(1)O6 octahedra. The corner-sharing octahedral tilt angles are 63°. Si(1) is bonded to four equivalent O(2) atoms to form SiO4 tetrahedra that share corners with eight equivalent Na(1)O6 octahedra and corners with four equivalent Ti(1)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles are 60°. There are two inequivalent O sites. In the first O site, O(1) is bonded in a 5-coordinate geometry to four equivalent Na(1) and one Ti(1) atom. In the second O site, O(2) is bonded in a rectangular see-saw-like geometry to two equivalent Na(1), one Ti(1), and one Si(1) atom.
Na2TiSiO5 crystallizes in the tetragonal P4/nmm space group. Na(1) is bonded to two equivalent O(1) and four equivalent O(2) atoms to form NaO6 octahedra that share corners with two equivalent Na(1)O6 octahedra, corners with four equivalent Si(1)O4 tetrahedra, corners with two equivalent Ti(1)O5 trigonal bipyramids, edges with four equivalent Na(1)O6 octahedra, and edges with two equivalent Ti(1)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles are 53°. Both Na(1)-O(1) bond lengths are 2.55 Å. All Na(1)-O(2) bond lengths are 2.29 Å. Ti(1) is bonded to one O(1) and four equivalent O(2) atoms to form distorted TiO5 trigonal bipyramids that share corners with four equivalent Na(1)O6 octahedra, corners with four equivalent Si(1)O4 tetrahedra, and edges with four equivalent Na(1)O6 octahedra. The corner-sharing octahedral tilt angles are 63°. The Ti(1)-O(1) bond length is 1.72 Å. All Ti(1)-O(2) bond lengths are 1.98 Å. Si(1) is bonded to four equivalent O(2) atoms to form SiO4 tetrahedra that share corners with eight equivalent Na(1)O6 octahedra and corners with four equivalent Ti(1)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles are 60°. All Si(1)-O(2) bond lengths are 1.63 Å. There are two inequivalent O sites. In the first O site, O(1) is bonded in a 5-coordinate geometry to four equivalent Na(1) and one Ti(1) atom. In the second O site, O(2) is bonded in a rectangular see-saw-like geometry to two equivalent Na(1), one Ti(1), and one Si(1) atom.