HfO2 is Cotunnite structured and crystallizes in the orthorhombic Pnma space group. Hf(1) is bonded in a 9-coordinate geometry to four equivalent O(2) and five equivalent O(1) atoms. There are two inequivalent O sites. In the first O site, O(2) is bonded to four equivalent Hf(1) atoms to form a mixture of corner and edge-sharing OHf4 tetrahedra. In the second O site, O(1) is bonded in a 5-coordinate geometry to five equivalent Hf(1) atoms.
HfO2 is Cotunnite structured and crystallizes in the orthorhombic Pnma space group. Hf(1) is bonded in a 9-coordinate geometry to four equivalent O(2) and five equivalent O(1) atoms. There are three shorter (2.14 Å) and one longer (2.17 Å) Hf(1)-O(2) bond length. There are a spread of Hf(1)-O(1) bond distances ranging from 2.16-2.59 Å. There are two inequivalent O sites. In the first O site, O(2) is bonded to four equivalent Hf(1) atoms to form a mixture of corner and edge-sharing OHf4 tetrahedra. In the second O site, O(1) is bonded in a 5-coordinate geometry to five equivalent Hf(1) atoms.