TmY3 is Magnesium-derived structured and crystallizes in the hexagonal P6_3/mmc space group. Tm(1) is bonded to twelve equivalent Y(1) atoms to form TmY12 cuboctahedra that share corners with six equivalent Tm(1)Y12 cuboctahedra, corners with twelve equivalent Y(1)Y8Tm4 cuboctahedra, edges with eighteen equivalent Y(1)Y8Tm4 cuboctahedra, faces with eight equivalent Tm(1)Y12 cuboctahedra, and faces with twelve equivalent Y(1)Y8Tm4 cuboctahedra. Y(1) is bonded to four equivalent Tm(1) and eight equivalent Y(1) atoms to form YY8Tm4 cuboctahedra that share corners with four equivalent Tm(1)Y12 cuboctahedra, corners with fourteen equivalent Y(1)Y8Tm4 cuboctahedra, edges with six equivalent Tm(1)Y12 cuboctahedra, edges with twelve equivalent Y(1)Y8Tm4 cuboctahedra, faces with four equivalent Tm(1)Y12 cuboctahedra, and faces with sixteen equivalent Y(1)Y8Tm4 cuboctahedra.
TmY3 is Magnesium-derived structured and crystallizes in the hexagonal P6_3/mmc space group. Tm(1) is bonded to twelve equivalent Y(1) atoms to form TmY12 cuboctahedra that share corners with six equivalent Tm(1)Y12 cuboctahedra, corners with twelve equivalent Y(1)Y8Tm4 cuboctahedra, edges with eighteen equivalent Y(1)Y8Tm4 cuboctahedra, faces with eight equivalent Tm(1)Y12 cuboctahedra, and faces with twelve equivalent Y(1)Y8Tm4 cuboctahedra. There are six shorter (3.57 Å) and six longer (3.61 Å) Tm(1)-Y(1) bond lengths. Y(1) is bonded to four equivalent Tm(1) and eight equivalent Y(1) atoms to form YY8Tm4 cuboctahedra that share corners with four equivalent Tm(1)Y12 cuboctahedra, corners with fourteen equivalent Y(1)Y8Tm4 cuboctahedra, edges with six equivalent Tm(1)Y12 cuboctahedra, edges with twelve equivalent Y(1)Y8Tm4 cuboctahedra, faces with four equivalent Tm(1)Y12 cuboctahedra, and faces with sixteen equivalent Y(1)Y8Tm4 cuboctahedra. There are six shorter (3.59 Å) and two longer (3.64 Å) Y(1)-Y(1) bond lengths.