BaSrHf4O12 crystallizes in the orthorhombic Amm2 space group. Ba(1) is bonded to two equivalent O(2), two equivalent O(3), four equivalent O(1), and four equivalent O(4) atoms to form distorted BaO12 cuboctahedra that share corners with four equivalent Ba(1)O12 cuboctahedra, corners with eight equivalent Sr(1)O12 cuboctahedra, and faces with eight equivalent Hf(1)O6 octahedra. Sr(1) is bonded to two equivalent O(2), two equivalent O(3), four equivalent O(1), and four equivalent O(5) atoms to form distorted SrO12 cuboctahedra that share corners with four equivalent Sr(1)O12 cuboctahedra, corners with eight equivalent Ba(1)O12 cuboctahedra, and faces with eight equivalent Hf(1)O6 octahedra. Hf(1) is bonded to one O(2), one O(3), one O(4), one O(5), and two equivalent O(1) atoms to form HfO6 octahedra that share corners with six equivalent Hf(1)O6 octahedra, faces with two equivalent Ba(1)O12 cuboctahedra, and faces with two equivalent Sr(1)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 4-15°. There are five inequivalent O sites. In the first O site, O(1) is bonded in a distorted linear geometry to one Ba(1), one Sr(1), and two equivalent Hf(1) atoms. In the second O site, O(2) is bonded in a distorted rectangular see-saw-like geometry to one Ba(1), one Sr(1), and two equivalent Hf(1) atoms. In the third O site, O(3) is bonded in a 3-coordinate geometry to one Ba(1), one Sr(1), and two equivalent Hf(1) atoms. In the fourth O site, O(4) is bonded in a distorted linear geometry to two equivalent Ba(1) and two equivalent Hf(1) atoms. In the fifth O site, O(5) is bonded in a 3-coordinate geometry to two equivalent Sr(1) and two equivalent Hf(1) atoms.
BaSrHf4O12 crystallizes in the orthorhombic Amm2 space group. Ba(1) is bonded to two equivalent O(2), two equivalent O(3), four equivalent O(1), and four equivalent O(4) atoms to form distorted BaO12 cuboctahedra that share corners with four equivalent Ba(1)O12 cuboctahedra, corners with eight equivalent Sr(1)O12 cuboctahedra, and faces with eight equivalent Hf(1)O6 octahedra. Both Ba(1)-O(2) bond lengths are 2.92 Å. Both Ba(1)-O(3) bond lengths are 3.26 Å. All Ba(1)-O(1) bond lengths are 2.87 Å. There are two shorter (2.90 Å) and two longer (2.96 Å) Ba(1)-O(4) bond lengths. Sr(1) is bonded to two equivalent O(2), two equivalent O(3), four equivalent O(1), and four equivalent O(5) atoms to form distorted SrO12 cuboctahedra that share corners with four equivalent Sr(1)O12 cuboctahedra, corners with eight equivalent Ba(1)O12 cuboctahedra, and faces with eight equivalent Hf(1)O6 octahedra. Both Sr(1)-O(2) bond lengths are 2.84 Å. Both Sr(1)-O(3) bond lengths are 2.71 Å. All Sr(1)-O(1) bond lengths are 2.98 Å. There are two shorter (2.67 Å) and two longer (3.19 Å) Sr(1)-O(5) bond lengths. Hf(1) is bonded to one O(2), one O(3), one O(4), one O(5), and two equivalent O(1) atoms to form HfO6 octahedra that share corners with six equivalent Hf(1)O6 octahedra, faces with two equivalent Ba(1)O12 cuboctahedra, and faces with two equivalent Sr(1)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 4-15°. The Hf(1)-O(2) bond length is 2.09 Å. The Hf(1)-O(3) bond length is 2.07 Å. The Hf(1)-O(4) bond length is 2.09 Å. The Hf(1)-O(5) bond length is 2.07 Å. There is one shorter (2.07 Å) and one longer (2.08 Å) Hf(1)-O(1) bond length. There are five inequivalent O sites. In the first O site, O(1) is bonded in a distorted linear geometry to one Ba(1), one Sr(1), and two equivalent Hf(1) atoms. In the second O site, O(2) is bonded in a distorted rectangular see-saw-like geometry to one Ba(1), one Sr(1), and two equivalent Hf(1) atoms. In the third O site, O(3) is bonded in a 3-coordinate geometry to one Ba(1), one Sr(1), and two equivalent Hf(1) atoms. In the fourth O site, O(4) is bonded in a distorted linear geometry to two equivalent Ba(1) and two equivalent Hf(1) atoms. In the fifth O site, O(5) is bonded in a 3-coordinate geometry to two equivalent Sr(1) and two equivalent Hf(1) atoms.