BaSrCeHfO6 is Orthorhombic Perovskite-derived structured and 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 Ce(1)O6 octahedra and faces with four equivalent Hf(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 Ce(1)O6 octahedra and faces with four equivalent Hf(1)O6 octahedra. In the third Ba site, Ba(3) is bonded in a 12-coordinate geometry to four equivalent O(1), four equivalent O(3), and four equivalent O(5) atoms. In the fourth Ba site, Ba(4) is bonded in a 8-coordinate geometry to four equivalent O(1) and four equivalent O(6) atoms. There are four inequivalent Sr sites. In the first Sr site, Sr(1) is bonded in a distorted body-centered cubic geometry to four equivalent O(1) and four equivalent O(5) atoms. In the second Sr site, Sr(2) is bonded in a distorted body-centered cubic geometry to four equivalent O(2) and four equivalent O(6) atoms. In the third Sr site, Sr(3) is bonded in a 8-coordinate geometry to four equivalent O(3) and four equivalent O(4) atoms. In the fourth Sr site, Sr(4) is bonded in a distorted rectangular see-saw-like geometry to four equivalent O(2) and four equivalent O(4) atoms. Ce(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 CeO6 octahedra that share corners with six equivalent Hf(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 16-24°. Hf(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 HfO6 octahedra that share corners with six equivalent Ce(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 16-24°. 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 Sr(1), one Ce(1), and one Hf(1) atom. In the second O site, O(6) is bonded in a 5-coordinate geometry to one Ba(2), one Ba(4), one Sr(2), one Ce(1), and one Hf(1) atom. In the third O site, O(1) is bonded in a 2-coordinate geometry to one Ba(1), one Ba(3), one Ba(4), one Sr(1), one Ce(1), and one Hf(1) atom. In the fourth O site, O(2) is bonded in a 3-coordinate geometry to one Ba(1), one Sr(2), one Sr(4), one Ce(1), and one Hf(1) atom. In the fifth O site, O(3) is bonded in a 5-coordinate geometry to one Ba(1), one Ba(3), one Sr(3), one Ce(1), and one Hf(1) atom. In the sixth O site, O(4) is bonded in a 5-coordinate geometry to one Ba(2), one Sr(3), one Sr(4), one Ce(1), and one Hf(1) atom.
BaSrCeHfO6 is Orthorhombic Perovskite-derived structured and 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 Ce(1)O6 octahedra and faces with four equivalent Hf(1)O6 octahedra. All Ba(1)-O(1) bond lengths are 3.03 Å. All Ba(1)-O(2) bond lengths are 3.07 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 Ce(1)O6 octahedra and faces with four equivalent Hf(1)O6 octahedra. All Ba(2)-O(4) bond lengths are 3.03 Å. All Ba(2)-O(5) bond lengths are 3.02 Å. All Ba(2)-O(6) bond lengths are 3.04 Å. In the third Ba site, Ba(3) is bonded in a 12-coordinate geometry to four equivalent O(1), four equivalent O(3), and four equivalent O(5) atoms. All Ba(3)-O(1) bond lengths are 3.33 Å. All Ba(3)-O(3) bond lengths are 2.74 Å. All Ba(3)-O(5) bond lengths are 3.11 Å. In the fourth Ba site, Ba(4) is bonded in a 8-coordinate geometry to four equivalent O(1) and four equivalent O(6) atoms. All Ba(4)-O(1) bond lengths are 2.74 Å. All Ba(4)-O(6) bond lengths are 3.09 Å. There are four inequivalent Sr sites. In the first Sr site, Sr(1) is bonded in a distorted body-centered cubic geometry to four equivalent O(1) and four equivalent O(5) atoms. All Sr(1)-O(1) bond lengths are 3.07 Å. All Sr(1)-O(5) bond lengths are 2.62 Å. In the second Sr site, Sr(2) is bonded in a distorted body-centered cubic geometry to four equivalent O(2) and four equivalent O(6) atoms. All Sr(2)-O(2) bond lengths are 3.05 Å. All Sr(2)-O(6) bond lengths are 2.59 Å. In the third Sr site, Sr(3) is bonded in a 8-coordinate geometry to four equivalent O(3) and four equivalent O(4) atoms. All Sr(3)-O(3) bond lengths are 3.04 Å. All Sr(3)-O(4) bond lengths are 2.59 Å. In the fourth Sr site, Sr(4) is bonded in a distorted rectangular see-saw-like geometry to four equivalent O(2) and four equivalent O(4) atoms. All Sr(4)-O(2) bond lengths are 2.62 Å. All Sr(4)-O(4) bond lengths are 3.10 Å. Ce(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 CeO6 octahedra that share corners with six equivalent Hf(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 16-24°. The Ce(1)-O(1) bond length is 2.28 Å. The Ce(1)-O(2) bond length is 2.27 Å. The Ce(1)-O(3) bond length is 2.24 Å. The Ce(1)-O(4) bond length is 2.24 Å. The Ce(1)-O(5) bond length is 2.27 Å. The Ce(1)-O(6) bond length is 2.27 Å. Hf(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 HfO6 octahedra that share corners with six equivalent Ce(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 16-24°. The Hf(1)-O(1) bond length is 2.11 Å. The Hf(1)-O(2) bond length is 2.11 Å. The Hf(1)-O(3) bond length is 2.09 Å. The Hf(1)-O(4) bond length is 2.09 Å. The Hf(1)-O(5) bond length is 2.10 Å. The Hf(1)-O(6) bond length is 2.10 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 Sr(1), one Ce(1), and one Hf(1) atom. In the second O site, O(6) is bonded in a 5-coordinate geometry to one Ba(2), one Ba(4), one Sr(2), one Ce(1), and one Hf(1) atom. In the third O site, O(1) is bonded in a 2-coordinate geometry to one Ba(1), one Ba(3), one Ba(4), one Sr(1), one Ce(1), and one Hf(1) atom. In the fourth O site, O(2) is bonded in a 3-coordinate geometry to one Ba(1), one Sr(2), one Sr(4), one Ce(1), and one Hf(1) atom. In the fifth O site, O(3) is bonded in a 5-coordinate geometry to one Ba(1), one Ba(3), one Sr(3), one Ce(1), and one Hf(1) atom. In the sixth O site, O(4) is bonded in a 5-coordinate geometry to one Ba(2), one Sr(3), one Sr(4), one Ce(1), and one Hf(1) atom.