TlAlSiO4 crystallizes in the orthorhombic Pnma space group. Tl(1) is bonded in a 4-coordinate geometry to four equivalent O(3) atoms. Al(1) is bonded to one O(1), one O(2), and two equivalent O(3) atoms to form AlO4 tetrahedra that share corners with four equivalent Si(1)O4 tetrahedra. Si(1) is bonded to one O(1), one O(2), and two equivalent O(3) atoms to form SiO4 tetrahedra that share corners with four equivalent Al(1)O4 tetrahedra. There are three inequivalent O sites. In the first O site, O(1) is bonded in a linear geometry to one Al(1) and one Si(1) atom. In the second O site, O(2) is bonded in a linear geometry to one Al(1) and one Si(1) atom. In the third O site, O(3) is bonded in a distorted bent 120 degrees geometry to two equivalent Tl(1), one Al(1), and one Si(1) atom.
TlAlSiO4 crystallizes in the orthorhombic Pnma space group. Tl(1) is bonded in a 4-coordinate geometry to four equivalent O(3) atoms. There are two shorter (2.85 Å) and two longer (2.90 Å) Tl(1)-O(3) bond lengths. Al(1) is bonded to one O(1), one O(2), and two equivalent O(3) atoms to form AlO4 tetrahedra that share corners with four equivalent Si(1)O4 tetrahedra. The Al(1)-O(1) bond length is 1.73 Å. The Al(1)-O(2) bond length is 1.74 Å. Both Al(1)-O(3) bond lengths are 1.78 Å. Si(1) is bonded to one O(1), one O(2), and two equivalent O(3) atoms to form SiO4 tetrahedra that share corners with four equivalent Al(1)O4 tetrahedra. The Si(1)-O(1) bond length is 1.61 Å. The Si(1)-O(2) bond length is 1.62 Å. Both Si(1)-O(3) bond lengths are 1.66 Å. There are three inequivalent O sites. In the first O site, O(1) is bonded in a linear geometry to one Al(1) and one Si(1) atom. In the second O site, O(2) is bonded in a linear geometry to one Al(1) and one Si(1) atom. In the third O site, O(3) is bonded in a distorted bent 120 degrees geometry to two equivalent Tl(1), one Al(1), and one Si(1) atom.