TlIn3 is beta Cu3Ti-like structured and crystallizes in the hexagonal P6_3/mmc space group. Tl(1) is bonded to twelve In(1,1) atoms to form TlIn12 cuboctahedra that share corners with six equivalent Tl(1)In12 cuboctahedra; corners with twelve In(1,1)Tl4In8 cuboctahedra; edges with eighteen In(1,1)Tl4In8 cuboctahedra; faces with eight equivalent Tl(1)In12 cuboctahedra; and faces with twelve In(1,1)Tl4In8 cuboctahedra. There are two inequivalent In sites. In the first In site, In(1) is bonded to four equivalent Tl(1) and eight In(1,1) atoms to form InTl4In8 cuboctahedra that share corners with four equivalent Tl(1)In12 cuboctahedra; corners with fourteen In(1,1)Tl4In8 cuboctahedra; edges with six equivalent Tl(1)In12 cuboctahedra; edges with twelve In(1,1)Tl4In8 cuboctahedra; faces with four equivalent Tl(1)In12 cuboctahedra; and faces with sixteen In(1,1)Tl4In8 cuboctahedra. In the second In site, In(1) is bonded to four equivalent Tl(1) and eight equivalent In(1) atoms to form InTl4In8 cuboctahedra that share corners with four equivalent Tl(1)In12 cuboctahedra; corners with fourteen In(1,1)Tl4In8 cuboctahedra; edges with six equivalent Tl(1)In12 cuboctahedra; edges with twelve equivalent In(1)Tl4In8 cuboctahedra; faces with four equivalent Tl(1)In12 cuboctahedra; and faces with sixteen In(1,1)Tl4In8 cuboctahedra.
TlIn3 is beta Cu3Ti-like structured and crystallizes in the hexagonal P6_3/mmc space group. Tl(1) is bonded to twelve In(1,1) atoms to form TlIn12 cuboctahedra that share corners with six equivalent Tl(1)In12 cuboctahedra; corners with twelve In(1,1)Tl4In8 cuboctahedra; edges with eighteen In(1,1)Tl4In8 cuboctahedra; faces with eight equivalent Tl(1)In12 cuboctahedra; and faces with twelve In(1,1)Tl4In8 cuboctahedra. There are six shorter (3.39 Å) and six longer (3.42 Å) Tl(1)-In(1,1) bond lengths. There are two inequivalent In sites. In the first In site, In(1) is bonded to four equivalent Tl(1) and eight In(1,1) atoms to form InTl4In8 cuboctahedra that share corners with four equivalent Tl(1)In12 cuboctahedra; corners with fourteen In(1,1)Tl4In8 cuboctahedra; edges with six equivalent Tl(1)In12 cuboctahedra; edges with twelve In(1,1)Tl4In8 cuboctahedra; faces with four equivalent Tl(1)In12 cuboctahedra; and faces with sixteen In(1,1)Tl4In8 cuboctahedra. There are a spread of In(1)-In(1,1) bond distances ranging from 3.33-3.45 Å. In the second In site, In(1) is bonded to four equivalent Tl(1) and eight equivalent In(1) atoms to form InTl4In8 cuboctahedra that share corners with four equivalent Tl(1)In12 cuboctahedra; corners with fourteen In(1,1)Tl4In8 cuboctahedra; edges with six equivalent Tl(1)In12 cuboctahedra; edges with twelve equivalent In(1)Tl4In8 cuboctahedra; faces with four equivalent Tl(1)In12 cuboctahedra; and faces with sixteen In(1,1)Tl4In8 cuboctahedra.