HfO2 is Hydrophilite-like structured and crystallizes in the orthorhombic Pbcn space group. There are two inequivalent Hf sites. In the first Hf site, Hf(1) is bonded to one O(2), two equivalent O(3), and three equivalent O(1) atoms to form a mixture of edge and corner-sharing HfO6 octahedra. The corner-sharing octahedral tilt angles range from 49-54°. In the second Hf site, Hf(2) is bonded to two equivalent O(3) and four equivalent O(2) atoms to form a mixture of edge and corner-sharing HfO6 octahedra. The corner-sharing octahedral tilt angles range from 51-54°. There are three inequivalent O sites. In the first O site, O(1) is bonded in a trigonal planar geometry to three equivalent Hf(1) atoms. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to one Hf(1) and two equivalent Hf(2) atoms. In the third O site, O(3) is bonded in a trigonal planar geometry to one Hf(2) and two equivalent Hf(1) atoms.
HfO2 is Hydrophilite-like structured and crystallizes in the orthorhombic Pbcn space group. There are two inequivalent Hf sites. In the first Hf site, Hf(1) is bonded to one O(2), two equivalent O(3), and three equivalent O(1) atoms to form a mixture of edge and corner-sharing HfO6 octahedra. The corner-sharing octahedral tilt angles range from 49-54°. The Hf(1)-O(2) bond length is 2.08 Å. There is one shorter (2.08 Å) and one longer (2.09 Å) Hf(1)-O(3) bond length. All Hf(1)-O(1) bond lengths are 2.08 Å. In the second Hf site, Hf(2) is bonded to two equivalent O(3) and four equivalent O(2) atoms to form a mixture of edge and corner-sharing HfO6 octahedra. The corner-sharing octahedral tilt angles range from 51-54°. Both Hf(2)-O(3) bond lengths are 2.08 Å. There are two shorter (2.02 Å) and two longer (2.15 Å) Hf(2)-O(2) bond lengths. There are three inequivalent O sites. In the first O site, O(1) is bonded in a trigonal planar geometry to three equivalent Hf(1) atoms. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to one Hf(1) and two equivalent Hf(2) atoms. In the third O site, O(3) is bonded in a trigonal planar geometry to one Hf(2) and two equivalent Hf(1) atoms.