Tm3Sm is beta Cu3Ti-like structured and crystallizes in the hexagonal P6_3/mmc space group. There are two inequivalent Tm sites. In the first Tm site, Tm(1) is bonded to eight Tm(1,1) and four equivalent Sm(1) atoms to form TmSm4Tm8 cuboctahedra that share corners with four equivalent Sm(1)Tm12 cuboctahedra; corners with fourteen Tm(1,1)Sm4Tm8 cuboctahedra; edges with six equivalent Sm(1)Tm12 cuboctahedra; edges with twelve Tm(1,1)Sm4Tm8 cuboctahedra; faces with four equivalent Sm(1)Tm12 cuboctahedra; and faces with sixteen Tm(1,1)Sm4Tm8 cuboctahedra. In the second Tm site, Tm(1) is bonded to eight Tm(1,1) and four equivalent Sm(1) atoms to form TmSm4Tm8 cuboctahedra that share corners with four equivalent Sm(1)Tm12 cuboctahedra; corners with fourteen Tm(1,1)Sm4Tm8 cuboctahedra; edges with six equivalent Sm(1)Tm12 cuboctahedra; edges with twelve Tm(1,1)Sm4Tm8 cuboctahedra; faces with four equivalent Sm(1)Tm12 cuboctahedra; and faces with sixteen Tm(1,1)Sm4Tm8 cuboctahedra. Sm(1) is bonded to twelve Tm(1,1) atoms to form SmTm12 cuboctahedra that share corners with six equivalent Sm(1)Tm12 cuboctahedra; corners with twelve equivalent Tm(1)Sm4Tm8 cuboctahedra; edges with eighteen Tm(1,1)Sm4Tm8 cuboctahedra; faces with eight equivalent Sm(1)Tm12 cuboctahedra; and faces with twelve Tm(1,1)Sm4Tm8 cuboctahedra.
Tm3Sm is beta Cu3Ti-like structured and crystallizes in the hexagonal P6_3/mmc space group. There are two inequivalent Tm sites. In the first Tm site, Tm(1) is bonded to eight Tm(1,1) and four equivalent Sm(1) atoms to form TmSm4Tm8 cuboctahedra that share corners with four equivalent Sm(1)Tm12 cuboctahedra; corners with fourteen Tm(1,1)Sm4Tm8 cuboctahedra; edges with six equivalent Sm(1)Tm12 cuboctahedra; edges with twelve Tm(1,1)Sm4Tm8 cuboctahedra; faces with four equivalent Sm(1)Tm12 cuboctahedra; and faces with sixteen Tm(1,1)Sm4Tm8 cuboctahedra. There are a spread of Tm(1)-Tm(1,1) bond distances ranging from 3.46-3.65 Å. There are two shorter (3.49 Å) and two longer (3.60 Å) Tm(1)-Sm(1) bond lengths. In the second Tm site, Tm(1) is bonded to eight Tm(1,1) and four equivalent Sm(1) atoms to form TmSm4Tm8 cuboctahedra that share corners with four equivalent Sm(1)Tm12 cuboctahedra; corners with fourteen Tm(1,1)Sm4Tm8 cuboctahedra; edges with six equivalent Sm(1)Tm12 cuboctahedra; edges with twelve Tm(1,1)Sm4Tm8 cuboctahedra; faces with four equivalent Sm(1)Tm12 cuboctahedra; and faces with sixteen Tm(1,1)Sm4Tm8 cuboctahedra. All Tm(1)-Tm(1) bond lengths are 3.46 Å. There are two shorter (3.49 Å) and two longer (3.60 Å) Tm(1)-Sm(1) bond lengths. Sm(1) is bonded to twelve Tm(1,1) atoms to form SmTm12 cuboctahedra that share corners with six equivalent Sm(1)Tm12 cuboctahedra; corners with twelve equivalent Tm(1)Sm4Tm8 cuboctahedra; edges with eighteen Tm(1,1)Sm4Tm8 cuboctahedra; faces with eight equivalent Sm(1)Tm12 cuboctahedra; and faces with twelve Tm(1,1)Sm4Tm8 cuboctahedra.