TlAlSiO4 crystallizes in the orthorhombic Pnma space group. Tl(1) is bonded in a distorted single-bond geometry to one O(3) atom. Al(1) is bonded in a distorted pentagonal planar geometry to one O(2) and four equivalent O(1) atoms. Si(1) is bonded in a tetrahedral geometry to one O(2), one O(3), and two equivalent O(1) atoms. There are three inequivalent O sites. In the first O site, O(1) is bonded in a distorted T-shaped geometry to two equivalent 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 linear geometry to one Tl(1) and one Si(1) atom.
TlAlSiO4 crystallizes in the orthorhombic Pnma space group. Tl(1) is bonded in a distorted single-bond geometry to one O(3) atom. The Tl(1)-O(3) bond length is 2.29 Å. Al(1) is bonded in a distorted pentagonal planar geometry to one O(2) and four equivalent O(1) atoms. The Al(1)-O(2) bond length is 1.80 Å. There are two shorter (1.91 Å) and two longer (2.00 Å) Al(1)-O(1) bond lengths. Si(1) is bonded in a tetrahedral geometry to one O(2), one O(3), and two equivalent O(1) atoms. The Si(1)-O(2) bond length is 1.65 Å. The Si(1)-O(3) bond length is 1.56 Å. Both Si(1)-O(1) bond lengths are 1.74 Å. There are three inequivalent O sites. In the first O site, O(1) is bonded in a distorted T-shaped geometry to two equivalent 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 linear geometry to one Tl(1) and one Si(1) atom.