YbTm3 is beta Cu3Ti-like structured and crystallizes in the tetragonal I4/mmm space group. Yb(1) is bonded to four equivalent Tm(2) and eight equivalent Tm(1) atoms to form YbTm12 cuboctahedra that share corners with four equivalent Yb(1)Tm12 cuboctahedra, corners with eight equivalent Tm(2)Yb4Tm8 cuboctahedra, edges with eight equivalent Yb(1)Tm12 cuboctahedra, edges with sixteen equivalent Tm(1)Yb4Tm8 cuboctahedra, faces with four equivalent Yb(1)Tm12 cuboctahedra, faces with six equivalent Tm(2)Yb4Tm8 cuboctahedra, and faces with eight equivalent Tm(1)Yb4Tm8 cuboctahedra. There are two inequivalent Tm sites. In the first Tm site, Tm(1) is bonded to four equivalent Yb(1), four equivalent Tm(1), and four equivalent Tm(2) atoms to form TmYb4Tm8 cuboctahedra that share corners with twelve equivalent Tm(1)Yb4Tm8 cuboctahedra, edges with eight equivalent Yb(1)Tm12 cuboctahedra, edges with eight equivalent Tm(1)Yb4Tm8 cuboctahedra, edges with eight equivalent Tm(2)Yb4Tm8 cuboctahedra, faces with four equivalent Yb(1)Tm12 cuboctahedra, faces with four equivalent Tm(2)Yb4Tm8 cuboctahedra, and faces with ten equivalent Tm(1)Yb4Tm8 cuboctahedra. In the second Tm site, Tm(2) is bonded to four equivalent Yb(1) and eight equivalent Tm(1) atoms to form TmYb4Tm8 cuboctahedra that share corners with four equivalent Tm(2)Yb4Tm8 cuboctahedra, corners with eight equivalent Yb(1)Tm12 cuboctahedra, edges with eight equivalent Tm(2)Yb4Tm8 cuboctahedra, edges with sixteen equivalent Tm(1)Yb4Tm8 cuboctahedra, faces with four equivalent Tm(2)Yb4Tm8 cuboctahedra, faces with six equivalent Yb(1)Tm12 cuboctahedra, and faces with eight equivalent Tm(1)Yb4Tm8 cuboctahedra.
YbTm3 is beta Cu3Ti-like structured and crystallizes in the tetragonal I4/mmm space group. Yb(1) is bonded to four equivalent Tm(2) and eight equivalent Tm(1) atoms to form YbTm12 cuboctahedra that share corners with four equivalent Yb(1)Tm12 cuboctahedra, corners with eight equivalent Tm(2)Yb4Tm8 cuboctahedra, edges with eight equivalent Yb(1)Tm12 cuboctahedra, edges with sixteen equivalent Tm(1)Yb4Tm8 cuboctahedra, faces with four equivalent Yb(1)Tm12 cuboctahedra, faces with six equivalent Tm(2)Yb4Tm8 cuboctahedra, and faces with eight equivalent Tm(1)Yb4Tm8 cuboctahedra. All Yb(1)-Tm(2) bond lengths are 3.53 Å. All Yb(1)-Tm(1) bond lengths are 3.55 Å. There are two inequivalent Tm sites. In the first Tm site, Tm(1) is bonded to four equivalent Yb(1), four equivalent Tm(1), and four equivalent Tm(2) atoms to form TmYb4Tm8 cuboctahedra that share corners with twelve equivalent Tm(1)Yb4Tm8 cuboctahedra, edges with eight equivalent Yb(1)Tm12 cuboctahedra, edges with eight equivalent Tm(1)Yb4Tm8 cuboctahedra, edges with eight equivalent Tm(2)Yb4Tm8 cuboctahedra, faces with four equivalent Yb(1)Tm12 cuboctahedra, faces with four equivalent Tm(2)Yb4Tm8 cuboctahedra, and faces with ten equivalent Tm(1)Yb4Tm8 cuboctahedra. All Tm(1)-Tm(1) bond lengths are 3.53 Å. All Tm(1)-Tm(2) bond lengths are 3.55 Å. In the second Tm site, Tm(2) is bonded to four equivalent Yb(1) and eight equivalent Tm(1) atoms to form TmYb4Tm8 cuboctahedra that share corners with four equivalent Tm(2)Yb4Tm8 cuboctahedra, corners with eight equivalent Yb(1)Tm12 cuboctahedra, edges with eight equivalent Tm(2)Yb4Tm8 cuboctahedra, edges with sixteen equivalent Tm(1)Yb4Tm8 cuboctahedra, faces with four equivalent Tm(2)Yb4Tm8 cuboctahedra, faces with six equivalent Yb(1)Tm12 cuboctahedra, and faces with eight equivalent Tm(1)Yb4Tm8 cuboctahedra.