BaEu3 is beta Cu3Ti-like structured and crystallizes in the hexagonal P6_3/mmc space group. Ba(1) is bonded to twelve Eu(1,1) atoms to form BaEu12 cuboctahedra that share corners with six equivalent Ba(1)Eu12 cuboctahedra; corners with twelve Eu(1,1)Ba4Eu8 cuboctahedra; edges with eighteen Eu(1,1)Ba4Eu8 cuboctahedra; faces with eight equivalent Ba(1)Eu12 cuboctahedra; and faces with twelve Eu(1,1)Ba4Eu8 cuboctahedra. There are two inequivalent Eu sites. In the first Eu site, Eu(1) is bonded to four equivalent Ba(1) and eight Eu(1,1) atoms to form distorted EuBa4Eu8 cuboctahedra that share corners with four equivalent Ba(1)Eu12 cuboctahedra; corners with fourteen Eu(1,1)Ba4Eu8 cuboctahedra; edges with six equivalent Ba(1)Eu12 cuboctahedra; edges with twelve Eu(1,1)Ba4Eu8 cuboctahedra; faces with four equivalent Ba(1)Eu12 cuboctahedra; and faces with sixteen Eu(1,1)Ba4Eu8 cuboctahedra. In the second Eu site, Eu(1) is bonded to four equivalent Ba(1) and eight Eu(1,1) atoms to form distorted EuBa4Eu8 cuboctahedra that share corners with four equivalent Ba(1)Eu12 cuboctahedra; corners with fourteen Eu(1,1)Ba4Eu8 cuboctahedra; edges with six equivalent Ba(1)Eu12 cuboctahedra; edges with twelve Eu(1,1)Ba4Eu8 cuboctahedra; faces with four equivalent Ba(1)Eu12 cuboctahedra; and faces with sixteen Eu(1,1)Ba4Eu8 cuboctahedra.
BaEu3 is beta Cu3Ti-like structured and crystallizes in the hexagonal P6_3/mmc space group. Ba(1) is bonded to twelve Eu(1,1) atoms to form BaEu12 cuboctahedra that share corners with six equivalent Ba(1)Eu12 cuboctahedra; corners with twelve Eu(1,1)Ba4Eu8 cuboctahedra; edges with eighteen Eu(1,1)Ba4Eu8 cuboctahedra; faces with eight equivalent Ba(1)Eu12 cuboctahedra; and faces with twelve Eu(1,1)Ba4Eu8 cuboctahedra. There are six shorter (4.11 Å) and six longer (4.12 Å) Ba(1)-Eu(1,1) bond lengths. There are two inequivalent Eu sites. In the first Eu site, Eu(1) is bonded to four equivalent Ba(1) and eight Eu(1,1) atoms to form distorted EuBa4Eu8 cuboctahedra that share corners with four equivalent Ba(1)Eu12 cuboctahedra; corners with fourteen Eu(1,1)Ba4Eu8 cuboctahedra; edges with six equivalent Ba(1)Eu12 cuboctahedra; edges with twelve Eu(1,1)Ba4Eu8 cuboctahedra; faces with four equivalent Ba(1)Eu12 cuboctahedra; and faces with sixteen Eu(1,1)Ba4Eu8 cuboctahedra. There are six shorter (4.07 Å) and two longer (4.18 Å) Eu(1)-Eu(1,1) bond lengths. In the second Eu site, Eu(1) is bonded to four equivalent Ba(1) and eight Eu(1,1) atoms to form distorted EuBa4Eu8 cuboctahedra that share corners with four equivalent Ba(1)Eu12 cuboctahedra; corners with fourteen Eu(1,1)Ba4Eu8 cuboctahedra; edges with six equivalent Ba(1)Eu12 cuboctahedra; edges with twelve Eu(1,1)Ba4Eu8 cuboctahedra; faces with four equivalent Ba(1)Eu12 cuboctahedra; and faces with sixteen Eu(1,1)Ba4Eu8 cuboctahedra. Both Eu(1)-Eu(1) bond lengths are 4.07 Å.