Rb3NaTiO4 crystallizes in the monoclinic P2_1/c space group. There are three inequivalent Rb sites. In the first Rb site, Rb(1) is bonded in a 5-coordinate geometry to one O(4), two equivalent O(1), and two equivalent O(3) atoms. In the second Rb site, Rb(2) is bonded in a 6-coordinate geometry to one O(1), one O(3), two equivalent O(2), and two equivalent O(4) atoms. In the third Rb site, Rb(3) is bonded in a 5-coordinate geometry to one O(1), one O(4), and three equivalent O(2) atoms. Na(1) is bonded to one O(1), one O(4), and two equivalent O(3) atoms to form NaO4 tetrahedra that share corners with four equivalent Ti(1)O4 tetrahedra and  an edgeedge with one Na(1)O4 tetrahedra. Ti(1) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form TiO4 tetrahedra that share corners with four equivalent Na(1)O4 tetrahedra. There are four inequivalent O sites. In the first O site, O(1) is bonded in a 6-coordinate geometry to one Rb(2), one Rb(3), two equivalent Rb(1), one Na(1), and one Ti(1) atom. In the second O site, O(2) is bonded in a distorted single-bond geometry to two equivalent Rb(2), three equivalent Rb(3), and one Ti(1) atom. In the third O site, O(3) is bonded in a 3-coordinate geometry to one Rb(2), two equivalent Rb(1), two equivalent Na(1), and one Ti(1) atom. In the fourth O site, O(4) is bonded in a 2-coordinate geometry to one Rb(1), one Rb(3), two equivalent Rb(2), one Na(1), and one Ti(1) atom.
Rb3NaTiO4 crystallizes in the monoclinic P2_1/c space group. There are three inequivalent Rb sites. In the first Rb site, Rb(1) is bonded in a 5-coordinate geometry to one O(4), two equivalent O(1), and two equivalent O(3) atoms. The Rb(1)-O(4) bond length is 2.94 Å. There is one shorter (2.88 Å) and one longer (2.95 Å) Rb(1)-O(1) bond length. There is one shorter (2.96 Å) and one longer (3.00 Å) Rb(1)-O(3) bond length. In the second Rb site, Rb(2) is bonded in a 6-coordinate geometry to one O(1), one O(3), two equivalent O(2), and two equivalent O(4) atoms. The Rb(2)-O(1) bond length is 2.84 Å. The Rb(2)-O(3) bond length is 3.22 Å. There is one shorter (2.88 Å) and one longer (2.89 Å) Rb(2)-O(2) bond length. There is one shorter (3.05 Å) and one longer (3.38 Å) Rb(2)-O(4) bond length. In the third Rb site, Rb(3) is bonded in a 5-coordinate geometry to one O(1), one O(4), and three equivalent O(2) atoms. The Rb(3)-O(1) bond length is 2.81 Å. The Rb(3)-O(4) bond length is 3.14 Å. There are a spread of Rb(3)-O(2) bond distances ranging from 2.90-2.95 Å. Na(1) is bonded to one O(1), one O(4), and two equivalent O(3) atoms to form NaO4 tetrahedra that share corners with four equivalent Ti(1)O4 tetrahedra and  an edgeedge with one Na(1)O4 tetrahedra. The Na(1)-O(1) bond length is 2.34 Å. The Na(1)-O(4) bond length is 2.38 Å. There is one shorter (2.37 Å) and one longer (2.45 Å) Na(1)-O(3) bond length. Ti(1) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form TiO4 tetrahedra that share corners with four equivalent Na(1)O4 tetrahedra. The Ti(1)-O(1) bond length is 1.84 Å. The Ti(1)-O(2) bond length is 1.84 Å. The Ti(1)-O(3) bond length is 1.86 Å. The Ti(1)-O(4) bond length is 1.86 Å. There are four inequivalent O sites. In the first O site, O(1) is bonded in a 6-coordinate geometry to one Rb(2), one Rb(3), two equivalent Rb(1), one Na(1), and one Ti(1) atom. In the second O site, O(2) is bonded in a distorted single-bond geometry to two equivalent Rb(2), three equivalent Rb(3), and one Ti(1) atom. In the third O site, O(3) is bonded in a 3-coordinate geometry to one Rb(2), two equivalent Rb(1), two equivalent Na(1), and one Ti(1) atom. In the fourth O site, O(4) is bonded in a 2-coordinate geometry to one Rb(1), one Rb(3), two equivalent Rb(2), one Na(1), and one Ti(1) atom.