BaCaEuBiO6 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 Eu(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 Eu(1)O6 octahedra and faces with four equivalent Bi(1)O6 octahedra. In the third Ba site, Ba(3) is bonded in a distorted square co-planar geometry to four equivalent O(3) and four equivalent O(5) atoms. In the fourth Ba site, Ba(4) is bonded in a distorted body-centered cubic geometry to four equivalent O(1) and four equivalent O(6) atoms. There are four inequivalent Ca sites. In the first Ca site, Ca(1) is bonded in a square co-planar geometry to four equivalent O(5) atoms. In the second Ca site, Ca(2) is bonded in a square co-planar geometry to four equivalent O(6) atoms. In the third Ca site, Ca(3) is bonded in a distorted square co-planar geometry to four equivalent O(3) and four equivalent O(4) atoms. In the fourth Ca site, Ca(4) is bonded in a square co-planar geometry to four equivalent O(2) atoms. Eu(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 EuO6 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 20-35°. 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 Eu(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 20-35°. There are six inequivalent O sites. In the first O site, O(5) is bonded in a 5-coordinate geometry to one Ba(2), one Ba(3), one Ca(1), one Eu(1), and one Bi(1) atom. In the second O site, O(6) is bonded in a 3-coordinate geometry to one Ba(2), one Ba(4), one Ca(2), one Eu(1), and one Bi(1) atom. In the third O site, O(1) is bonded in a 4-coordinate geometry to one Ba(1), one Ba(4), one Eu(1), and one Bi(1) atom. In the fourth O site, O(2) is bonded in a 3-coordinate geometry to one Ba(1), one Ca(4), one Eu(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(3), one Ca(3), one Eu(1), and one Bi(1) atom. In the sixth O site, O(4) is bonded in a 3-coordinate geometry to one Ba(2), one Ca(3), one Eu(1), and one Bi(1) atom.
BaCaEuBiO6 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 Eu(1)O6 octahedra and faces with four equivalent Bi(1)O6 octahedra. All Ba(1)-O(1) bond lengths are 3.00 Å. All Ba(1)-O(2) bond lengths are 3.12 Å. All Ba(1)-O(3) bond lengths are 3.08 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 Eu(1)O6 octahedra and faces with four equivalent Bi(1)O6 octahedra. All Ba(2)-O(4) bond lengths are 3.01 Å. All Ba(2)-O(5) bond lengths are 3.02 Å. All Ba(2)-O(6) bond lengths are 3.08 Å. In the third Ba site, Ba(3) is bonded in a distorted square co-planar geometry to four equivalent O(3) and four equivalent O(5) atoms. All Ba(3)-O(3) bond lengths are 2.66 Å. All Ba(3)-O(5) bond lengths are 3.19 Å. In the fourth Ba site, Ba(4) is bonded in a distorted body-centered cubic geometry to four equivalent O(1) and four equivalent O(6) atoms. All Ba(4)-O(1) bond lengths are 2.67 Å. All Ba(4)-O(6) bond lengths are 3.14 Å. There are four inequivalent Ca sites. In the first Ca site, Ca(1) is bonded in a square co-planar geometry to four equivalent O(5) atoms. All Ca(1)-O(5) bond lengths are 2.42 Å. In the second Ca site, Ca(2) is bonded in a square co-planar geometry to four equivalent O(6) atoms. All Ca(2)-O(6) bond lengths are 2.39 Å. In the third Ca site, Ca(3) is bonded in a distorted square co-planar geometry to four equivalent O(3) and four equivalent O(4) atoms. All Ca(3)-O(3) bond lengths are 3.05 Å. All Ca(3)-O(4) bond lengths are 2.39 Å. In the fourth Ca site, Ca(4) is bonded in a square co-planar geometry to four equivalent O(2) atoms. All Ca(4)-O(2) bond lengths are 2.43 Å. Eu(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 EuO6 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 20-35°. The Eu(1)-O(1) bond length is 2.32 Å. The Eu(1)-O(2) bond length is 2.32 Å. The Eu(1)-O(3) bond length is 2.26 Å. The Eu(1)-O(4) bond length is 2.28 Å. The Eu(1)-O(5) bond length is 2.33 Å. The Eu(1)-O(6) bond length is 2.32 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 Eu(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 20-35°. The Bi(1)-O(1) bond length is 2.15 Å. The Bi(1)-O(2) bond length is 2.16 Å. The Bi(1)-O(3) bond length is 2.12 Å. The Bi(1)-O(4) bond length is 2.13 Å. The Bi(1)-O(5) bond length is 2.16 Å. The Bi(1)-O(6) bond length is 2.15 Å. There are six inequivalent O sites. In the first O site, O(5) is bonded in a 5-coordinate geometry to one Ba(2), one Ba(3), one Ca(1), one Eu(1), and one Bi(1) atom. In the second O site, O(6) is bonded in a 3-coordinate geometry to one Ba(2), one Ba(4), one Ca(2), one Eu(1), and one Bi(1) atom. In the third O site, O(1) is bonded in a 4-coordinate geometry to one Ba(1), one Ba(4), one Eu(1), and one Bi(1) atom. In the fourth O site, O(2) is bonded in a 3-coordinate geometry to one Ba(1), one Ca(4), one Eu(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(3), one Ca(3), one Eu(1), and one Bi(1) atom. In the sixth O site, O(4) is bonded in a 3-coordinate geometry to one Ba(2), one Ca(3), one Eu(1), and one Bi(1) atom.