Ba2EuNbO6 crystallizes in the cubic Pn-3 space group. There are two inequivalent Ba sites. In the first Ba site, Ba(1) is bonded to twelve equivalent O(1) atoms to form BaO12 cuboctahedra that share corners with twelve equivalent Ba(2)O12 cuboctahedra, faces with six equivalent Ba(2)O12 cuboctahedra, faces with four equivalent Eu(1)O6 octahedra, and faces with four equivalent Nb(1)O6 octahedra. In the second Ba site, Ba(2) is bonded to twelve equivalent O(1) atoms to form distorted BaO12 cuboctahedra that share corners with four equivalent Ba(1)O12 cuboctahedra, corners with eight equivalent Ba(2)O12 cuboctahedra, faces with two equivalent Ba(1)O12 cuboctahedra, faces with four equivalent Ba(2)O12 cuboctahedra, faces with four equivalent Eu(1)O6 octahedra, and faces with four equivalent Nb(1)O6 octahedra. Eu(1) is bonded to six equivalent O(1) atoms to form EuO6 octahedra that share corners with six equivalent Nb(1)O6 octahedra, faces with two equivalent Ba(1)O12 cuboctahedra, and faces with six equivalent Ba(2)O12 cuboctahedra. The corner-sharing octahedral tilt angles are 10°. Nb(1) is bonded to six equivalent O(1) atoms to form NbO6 octahedra that share corners with six equivalent Eu(1)O6 octahedra, faces with two equivalent Ba(1)O12 cuboctahedra, and faces with six equivalent Ba(2)O12 cuboctahedra. The corner-sharing octahedral tilt angles are 10°. O(1) is bonded in a 2-coordinate geometry to one Ba(1), three equivalent Ba(2), one Eu(1), and one Nb(1) atom.
Ba2EuNbO6 crystallizes in the cubic Pn-3 space group. There are two inequivalent Ba sites. In the first Ba site, Ba(1) is bonded to twelve equivalent O(1) atoms to form BaO12 cuboctahedra that share corners with twelve equivalent Ba(2)O12 cuboctahedra, faces with six equivalent Ba(2)O12 cuboctahedra, faces with four equivalent Eu(1)O6 octahedra, and faces with four equivalent Nb(1)O6 octahedra. All Ba(1)-O(1) bond lengths are 3.05 Å. In the second Ba site, Ba(2) is bonded to twelve equivalent O(1) atoms to form distorted BaO12 cuboctahedra that share corners with four equivalent Ba(1)O12 cuboctahedra, corners with eight equivalent Ba(2)O12 cuboctahedra, faces with two equivalent Ba(1)O12 cuboctahedra, faces with four equivalent Ba(2)O12 cuboctahedra, faces with four equivalent Eu(1)O6 octahedra, and faces with four equivalent Nb(1)O6 octahedra. There are a spread of Ba(2)-O(1) bond distances ranging from 2.86-3.25 Å. Eu(1) is bonded to six equivalent O(1) atoms to form EuO6 octahedra that share corners with six equivalent Nb(1)O6 octahedra, faces with two equivalent Ba(1)O12 cuboctahedra, and faces with six equivalent Ba(2)O12 cuboctahedra. The corner-sharing octahedral tilt angles are 10°. All Eu(1)-O(1) bond lengths are 2.31 Å. Nb(1) is bonded to six equivalent O(1) atoms to form NbO6 octahedra that share corners with six equivalent Eu(1)O6 octahedra, faces with two equivalent Ba(1)O12 cuboctahedra, and faces with six equivalent Ba(2)O12 cuboctahedra. The corner-sharing octahedral tilt angles are 10°. All Nb(1)-O(1) bond lengths are 2.03 Å. O(1) is bonded in a 2-coordinate geometry to one Ba(1), three equivalent Ba(2), one Eu(1), and one Nb(1) atom.