Tm3In is beta Cu3Ti-like structured and crystallizes in the hexagonal P6_3/mmc space group. Tm(1) is bonded to eight equivalent Tm(1) and four equivalent In(1) atoms to form distorted TmTm8In4 cuboctahedra that share corners with four equivalent In(1)Tm12 cuboctahedra, corners with fourteen equivalent Tm(1)Tm8In4 cuboctahedra, edges with six equivalent In(1)Tm12 cuboctahedra, edges with twelve equivalent Tm(1)Tm8In4 cuboctahedra, faces with four equivalent In(1)Tm12 cuboctahedra, and faces with sixteen equivalent Tm(1)Tm8In4 cuboctahedra. In(1) is bonded to twelve equivalent Tm(1) atoms to form InTm12 cuboctahedra that share corners with six equivalent In(1)Tm12 cuboctahedra, corners with twelve equivalent Tm(1)Tm8In4 cuboctahedra, edges with eighteen equivalent Tm(1)Tm8In4 cuboctahedra, faces with eight equivalent In(1)Tm12 cuboctahedra, and faces with twelve equivalent Tm(1)Tm8In4 cuboctahedra.
Tm3In is beta Cu3Ti-like structured and crystallizes in the hexagonal P6_3/mmc space group. Tm(1) is bonded to eight equivalent Tm(1) and four equivalent In(1) atoms to form distorted TmTm8In4 cuboctahedra that share corners with four equivalent In(1)Tm12 cuboctahedra, corners with fourteen equivalent Tm(1)Tm8In4 cuboctahedra, edges with six equivalent In(1)Tm12 cuboctahedra, edges with twelve equivalent Tm(1)Tm8In4 cuboctahedra, faces with four equivalent In(1)Tm12 cuboctahedra, and faces with sixteen equivalent Tm(1)Tm8In4 cuboctahedra. There are a spread of Tm(1)-Tm(1) bond distances ranging from 3.29-3.44 Å. There are two shorter (3.36 Å) and two longer (3.37 Å) Tm(1)-In(1) bond lengths. In(1) is bonded to twelve equivalent Tm(1) atoms to form InTm12 cuboctahedra that share corners with six equivalent In(1)Tm12 cuboctahedra, corners with twelve equivalent Tm(1)Tm8In4 cuboctahedra, edges with eighteen equivalent Tm(1)Tm8In4 cuboctahedra, faces with eight equivalent In(1)Tm12 cuboctahedra, and faces with twelve equivalent Tm(1)Tm8In4 cuboctahedra.