Sr3TiSi4H2O13 crystallizes in the monoclinic P2_1/m space group. There are three inequivalent Sr sites. In the first Sr site, Sr(1) is bonded in a 9-coordinate geometry to one H(1), one O(4), one O(5), two equivalent O(1), two equivalent O(3), and two equivalent O(7) atoms. In the second Sr site, Sr(2) is bonded in a 9-coordinate geometry to one H(1), one H(2), one O(8), two equivalent O(1), two equivalent O(3), and two equivalent O(6) atoms. In the third Sr site, Sr(3) is bonded in a 7-coordinate geometry to one H(2), two equivalent O(1), two equivalent O(2), and two equivalent O(6) atoms. Ti(1) is bonded to two equivalent O(3), two equivalent O(4), and two equivalent O(7) atoms to form TiO6 octahedra that share corners with two equivalent Ti(1)O6 octahedra, corners with two equivalent Si(1)O4 tetrahedra, and corners with two equivalent Si(2)O4 tetrahedra. The corner-sharing octahedral tilt angles are 15°. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(2), one O(3), one O(5), and one O(6) atom to form SiO4 tetrahedra that share  a cornercorner with one Ti(1)O6 octahedra,  a cornercorner with one Si(1)O4 tetrahedra, and  a cornercorner with one Si(2)O4 tetrahedra. The corner-sharing octahedral tilt angles are 49°. In the second Si site, Si(2) is bonded to one O(1), one O(2), one O(7), and one O(8) atom to form SiO4 tetrahedra that share  a cornercorner with one Ti(1)O6 octahedra,  a cornercorner with one Si(1)O4 tetrahedra, and  a cornercorner with one Si(2)O4 tetrahedra. The corner-sharing octahedral tilt angles are 48°. There are two inequivalent H sites. In the first H site, H(1) is bonded in a distorted bent 120 degrees geometry to one Sr(1) and one Sr(2) atom. In the second H site, H(2) is bonded in an L-shaped geometry to one Sr(2) and one Sr(3) atom. There are eight inequivalent O sites. In the first O site, O(4) is bonded in a distorted T-shaped geometry to one Sr(1) and two equivalent Ti(1) atoms. In the second O site, O(5) is bonded in a distorted bent 150 degrees geometry to one Sr(1) and two equivalent Si(1) atoms. In the third O site, O(6) is bonded in a 3-coordinate geometry to one Sr(2), one Sr(3), and one Si(1) atom. In the fourth O site, O(7) is bonded in a 3-coordinate geometry to one Sr(1), one Ti(1), and one Si(2) atom. In the fifth O site, O(8) is bonded in a distorted bent 150 degrees geometry to one Sr(2) and two equivalent Si(2) atoms. In the sixth O site, O(1) is bonded in a 4-coordinate geometry to one Sr(1), one Sr(2), one Sr(3), and one Si(2) atom. In the seventh O site, O(2) is bonded in a 3-coordinate geometry to one Sr(3), one Si(1), and one Si(2) atom. In the eighth O site, O(3) is bonded in a 4-coordinate geometry to one Sr(1), one Sr(2), one Ti(1), and one Si(1) atom.
Sr3TiSi4H2O13 crystallizes in the monoclinic P2_1/m space group. There are three inequivalent Sr sites. In the first Sr site, Sr(1) is bonded in a 9-coordinate geometry to one H(1), one O(4), one O(5), two equivalent O(1), two equivalent O(3), and two equivalent O(7) atoms. The Sr(1)-H(1) bond length is 2.77 Å. The Sr(1)-O(4) bond length is 2.59 Å. The Sr(1)-O(5) bond length is 2.77 Å. Both Sr(1)-O(1) bond lengths are 2.50 Å. Both Sr(1)-O(3) bond lengths are 2.77 Å. Both Sr(1)-O(7) bond lengths are 2.62 Å. In the second Sr site, Sr(2) is bonded in a 9-coordinate geometry to one H(1), one H(2), one O(8), two equivalent O(1), two equivalent O(3), and two equivalent O(6) atoms. The Sr(2)-H(1) bond length is 2.76 Å. The Sr(2)-H(2) bond length is 2.73 Å. The Sr(2)-O(8) bond length is 2.71 Å. Both Sr(2)-O(1) bond lengths are 2.74 Å. Both Sr(2)-O(3) bond lengths are 2.58 Å. Both Sr(2)-O(6) bond lengths are 2.58 Å. In the third Sr site, Sr(3) is bonded in a 7-coordinate geometry to one H(2), two equivalent O(1), two equivalent O(2), and two equivalent O(6) atoms. The Sr(3)-H(2) bond length is 2.83 Å. Both Sr(3)-O(1) bond lengths are 2.65 Å. Both Sr(3)-O(2) bond lengths are 2.65 Å. Both Sr(3)-O(6) bond lengths are 2.42 Å. Ti(1) is bonded to two equivalent O(3), two equivalent O(4), and two equivalent O(7) atoms to form TiO6 octahedra that share corners with two equivalent Ti(1)O6 octahedra, corners with two equivalent Si(1)O4 tetrahedra, and corners with two equivalent Si(2)O4 tetrahedra. The corner-sharing octahedral tilt angles are 15°. Both Ti(1)-O(3) bond lengths are 2.01 Å. Both Ti(1)-O(4) bond lengths are 1.95 Å. Both Ti(1)-O(7) bond lengths are 2.04 Å. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(2), one O(3), one O(5), and one O(6) atom to form SiO4 tetrahedra that share  a cornercorner with one Ti(1)O6 octahedra,  a cornercorner with one Si(1)O4 tetrahedra, and  a cornercorner with one Si(2)O4 tetrahedra. The corner-sharing octahedral tilt angles are 49°. The Si(1)-O(2) bond length is 1.67 Å. The Si(1)-O(3) bond length is 1.65 Å. The Si(1)-O(5) bond length is 1.65 Å. The Si(1)-O(6) bond length is 1.59 Å. In the second Si site, Si(2) is bonded to one O(1), one O(2), one O(7), and one O(8) atom to form SiO4 tetrahedra that share  a cornercorner with one Ti(1)O6 octahedra,  a cornercorner with one Si(1)O4 tetrahedra, and  a cornercorner with one Si(2)O4 tetrahedra. The corner-sharing octahedral tilt angles are 48°. The Si(2)-O(1) bond length is 1.62 Å. The Si(2)-O(2) bond length is 1.68 Å. The Si(2)-O(7) bond length is 1.63 Å. The Si(2)-O(8) bond length is 1.66 Å. There are two inequivalent H sites. In the first H site, H(1) is bonded in a distorted bent 120 degrees geometry to one Sr(1) and one Sr(2) atom. In the second H site, H(2) is bonded in an L-shaped geometry to one Sr(2) and one Sr(3) atom. There are eight inequivalent O sites. In the first O site, O(4) is bonded in a distorted T-shaped geometry to one Sr(1) and two equivalent Ti(1) atoms. In the second O site, O(5) is bonded in a distorted bent 150 degrees geometry to one Sr(1) and two equivalent Si(1) atoms. In the third O site, O(6) is bonded in a 3-coordinate geometry to one Sr(2), one Sr(3), and one Si(1) atom. In the fourth O site, O(7) is bonded in a 3-coordinate geometry to one Sr(1), one Ti(1), and one Si(2) atom. In the fifth O site, O(8) is bonded in a distorted bent 150 degrees geometry to one Sr(2) and two equivalent Si(2) atoms. In the sixth O site, O(1) is bonded in a 4-coordinate geometry to one Sr(1), one Sr(2), one Sr(3), and one Si(2) atom. In the seventh O site, O(2) is bonded in a 3-coordinate geometry to one Sr(3), one Si(1), and one Si(2) atom. In the eighth O site, O(3) is bonded in a 4-coordinate geometry to one Sr(1), one Sr(2), one Ti(1), and one Si(1) atom.