La3Tl5 crystallizes in the orthorhombic Cmcm space group. There are two inequivalent La sites. In the first La site, La(1) is bonded in a 9-coordinate geometry to one Tl(1), four equivalent Tl(2), and four equivalent Tl(3) atoms. In the second La site, La(2) is bonded in a 10-coordinate geometry to two equivalent Tl(1), four equivalent Tl(2), and four equivalent Tl(3) atoms. There are three inequivalent Tl sites. In the first Tl site, Tl(1) is bonded in a 5-coordinate geometry to one La(1), four equivalent La(2), two equivalent Tl(2), and four equivalent Tl(3) atoms. In the second Tl site, Tl(2) is bonded in a 10-coordinate geometry to two equivalent La(1), four equivalent La(2), one Tl(1), one Tl(2), and two equivalent Tl(3) atoms. In the third Tl site, Tl(3) is bonded in a 10-coordinate geometry to two equivalent La(1), four equivalent La(2), two equivalent Tl(1), and two equivalent Tl(2) atoms.
La3Tl5 crystallizes in the orthorhombic Cmcm space group. There are two inequivalent La sites. In the first La site, La(1) is bonded in a 9-coordinate geometry to one Tl(1), four equivalent Tl(2), and four equivalent Tl(3) atoms. The La(1)-Tl(1) bond length is 3.18 Å. There are two shorter (3.26 Å) and two longer (3.52 Å) La(1)-Tl(2) bond lengths. There are two shorter (3.27 Å) and two longer (3.87 Å) La(1)-Tl(3) bond lengths. In the second La site, La(2) is bonded in a 10-coordinate geometry to two equivalent Tl(1), four equivalent Tl(2), and four equivalent Tl(3) atoms. Both La(2)-Tl(1) bond lengths are 3.43 Å. There are two shorter (3.47 Å) and two longer (3.68 Å) La(2)-Tl(2) bond lengths. There are two shorter (3.34 Å) and two longer (3.61 Å) La(2)-Tl(3) bond lengths. There are three inequivalent Tl sites. In the first Tl site, Tl(1) is bonded in a 5-coordinate geometry to one La(1), four equivalent La(2), two equivalent Tl(2), and four equivalent Tl(3) atoms. Both Tl(1)-Tl(2) bond lengths are 3.31 Å. There are two shorter (3.40 Å) and two longer (3.56 Å) Tl(1)-Tl(3) bond lengths. In the second Tl site, Tl(2) is bonded in a 10-coordinate geometry to two equivalent La(1), four equivalent La(2), one Tl(1), one Tl(2), and two equivalent Tl(3) atoms. The Tl(2)-Tl(2) bond length is 3.56 Å. Both Tl(2)-Tl(3) bond lengths are 3.17 Å. In the third Tl site, Tl(3) is bonded in a 10-coordinate geometry to two equivalent La(1), four equivalent La(2), two equivalent Tl(1), and two equivalent Tl(2) atoms.