BaEuNbBiO6 crystallizes in the orthorhombic P222 space group. There are four inequivalent Ba sites. In the first Ba site, Ba(1) is bonded to four equivalent O(1), four equivalent O(2), and four equivalent O(3) atoms to form BaO12 cuboctahedra that share faces with four equivalent Nb(1)O6 octahedra and faces with four equivalent Bi(1)O6 octahedra. In the second Ba site, Ba(2) is bonded to four equivalent O(4), four equivalent O(5), and four equivalent O(6) atoms to form BaO12 cuboctahedra that share faces with four equivalent Nb(1)O6 octahedra and faces with four equivalent Bi(1)O6 octahedra. In the third Ba site, Ba(3) is bonded in a 4-coordinate geometry to four equivalent O(2) and four equivalent O(6) atoms. In the fourth Ba site, Ba(4) is bonded in a 8-coordinate geometry to four equivalent O(3) and four equivalent O(4) atoms. There are four inequivalent Eu sites. In the first Eu site, Eu(1) is bonded in a distorted rectangular see-saw-like geometry to four equivalent O(5) atoms. In the second Eu site, Eu(2) is bonded in a distorted square co-planar geometry to four equivalent O(2) and four equivalent O(4) atoms. In the third Eu site, Eu(3) is bonded in a distorted square co-planar geometry to four equivalent O(3) atoms. In the fourth Eu site, Eu(4) is bonded in a distorted body-centered cubic geometry to four equivalent O(1) and four equivalent O(6) atoms. Nb(1) is bonded to one O(1), one O(2), one O(3), one O(4), one O(5), and one O(6) atom to form NbO6 octahedra that share corners with six equivalent Bi(1)O6 octahedra,  a faceface with one Ba(1)O12 cuboctahedra, and  a faceface with one Ba(2)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 19-30°. Bi(1) is bonded to one O(1), one O(2), one O(3), one O(4), one O(5), and one O(6) atom to form BiO6 octahedra that share corners with six equivalent Nb(1)O6 octahedra,  a faceface with one Ba(1)O12 cuboctahedra, and  a faceface with one Ba(2)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 19-30°. There are six inequivalent O sites. In the first O site, O(5) is bonded in a 3-coordinate geometry to one Ba(2), one Eu(1), one Nb(1), and one Bi(1) atom. In the second O site, O(6) is bonded in a 5-coordinate geometry to one Ba(2), one Ba(3), one Eu(4), one Nb(1), and one Bi(1) atom. In the third O site, O(1) is bonded in a 3-coordinate geometry to one Ba(1), one Eu(4), one Nb(1), and one Bi(1) atom. In the fourth O site, O(2) is bonded in a 5-coordinate geometry to one Ba(1), one Ba(3), one Eu(2), one Nb(1), and one Bi(1) atom. In the fifth O site, O(3) is bonded in a 5-coordinate geometry to one Ba(1), one Ba(4), one Eu(3), one Nb(1), and one Bi(1) atom. In the sixth O site, O(4) is bonded in a 1-coordinate geometry to one Ba(2), one Ba(4), one Eu(2), one Nb(1), and one Bi(1) atom.
BaEuNbBiO6 crystallizes in the orthorhombic P222 space group. There are four inequivalent Ba sites. In the first Ba site, Ba(1) is bonded to four equivalent O(1), four equivalent O(2), and four equivalent O(3) atoms to form BaO12 cuboctahedra that share faces with four equivalent Nb(1)O6 octahedra and faces with four equivalent Bi(1)O6 octahedra. All Ba(1)-O(1) bond lengths are 3.02 Å. All Ba(1)-O(2) bond lengths are 3.01 Å. All Ba(1)-O(3) bond lengths are 3.06 Å. In the second Ba site, Ba(2) is bonded to four equivalent O(4), four equivalent O(5), and four equivalent O(6) atoms to form BaO12 cuboctahedra that share faces with four equivalent Nb(1)O6 octahedra and faces with four equivalent Bi(1)O6 octahedra. All Ba(2)-O(4) bond lengths are 2.99 Å. All Ba(2)-O(5) bond lengths are 3.12 Å. All Ba(2)-O(6) bond lengths are 3.11 Å. In the third Ba site, Ba(3) is bonded in a 4-coordinate geometry to four equivalent O(2) and four equivalent O(6) atoms. All Ba(3)-O(2) bond lengths are 3.18 Å. All Ba(3)-O(6) bond lengths are 2.70 Å. In the fourth Ba site, Ba(4) is bonded in a 8-coordinate geometry to four equivalent O(3) and four equivalent O(4) atoms. All Ba(4)-O(3) bond lengths are 3.15 Å. All Ba(4)-O(4) bond lengths are 2.70 Å. There are four inequivalent Eu sites. In the first Eu site, Eu(1) is bonded in a distorted rectangular see-saw-like geometry to four equivalent O(5) atoms. All Eu(1)-O(5) bond lengths are 2.50 Å. In the second Eu site, Eu(2) is bonded in a distorted square co-planar geometry to four equivalent O(2) and four equivalent O(4) atoms. All Eu(2)-O(2) bond lengths are 2.53 Å. All Eu(2)-O(4) bond lengths are 3.14 Å. In the third Eu site, Eu(3) is bonded in a distorted square co-planar geometry to four equivalent O(3) atoms. All Eu(3)-O(3) bond lengths are 2.46 Å. In the fourth Eu site, Eu(4) is bonded in a distorted body-centered cubic geometry to four equivalent O(1) and four equivalent O(6) atoms. All Eu(4)-O(1) bond lengths are 2.48 Å. All Eu(4)-O(6) bond lengths are 3.01 Å. Nb(1) is bonded to one O(1), one O(2), one O(3), one O(4), one O(5), and one O(6) atom to form NbO6 octahedra that share corners with six equivalent Bi(1)O6 octahedra,  a faceface with one Ba(1)O12 cuboctahedra, and  a faceface with one Ba(2)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 19-30°. The Nb(1)-O(1) bond length is 2.07 Å. The Nb(1)-O(2) bond length is 2.02 Å. The Nb(1)-O(3) bond length is 2.02 Å. The Nb(1)-O(4) bond length is 2.00 Å. The Nb(1)-O(5) bond length is 2.06 Å. The Nb(1)-O(6) bond length is 2.07 Å. Bi(1) is bonded to one O(1), one O(2), one O(3), one O(4), one O(5), and one O(6) atom to form BiO6 octahedra that share corners with six equivalent Nb(1)O6 octahedra,  a faceface with one Ba(1)O12 cuboctahedra, and  a faceface with one Ba(2)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 19-30°. The Bi(1)-O(1) bond length is 2.28 Å. The Bi(1)-O(2) bond length is 2.41 Å. The Bi(1)-O(3) bond length is 2.45 Å. The Bi(1)-O(4) bond length is 2.47 Å. The Bi(1)-O(5) bond length is 2.34 Å. The Bi(1)-O(6) bond length is 2.29 Å. There are six inequivalent O sites. In the first O site, O(5) is bonded in a 3-coordinate geometry to one Ba(2), one Eu(1), one Nb(1), and one Bi(1) atom. In the second O site, O(6) is bonded in a 5-coordinate geometry to one Ba(2), one Ba(3), one Eu(4), one Nb(1), and one Bi(1) atom. In the third O site, O(1) is bonded in a 3-coordinate geometry to one Ba(1), one Eu(4), one Nb(1), and one Bi(1) atom. In the fourth O site, O(2) is bonded in a 5-coordinate geometry to one Ba(1), one Ba(3), one Eu(2), one Nb(1), and one Bi(1) atom. In the fifth O site, O(3) is bonded in a 5-coordinate geometry to one Ba(1), one Ba(4), one Eu(3), one Nb(1), and one Bi(1) atom. In the sixth O site, O(4) is bonded in a 1-coordinate geometry to one Ba(2), one Ba(4), one Eu(2), one Nb(1), and one Bi(1) atom.