Materials Data on HfO2 by Materials Project

HfO2 is Baddeleyite structured and crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. Hf4+ is bonded to seven O2- atoms to form a mixture of distorted corner and edge-sharing HfO7 pentagonal bipyramids. There are a spread of Hf–O bond distances ranging from 2.05–2.26 Å. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted trigonal non-coplanar geometry to three equivalent Hf4+ atoms. In the second O2- site, O2- is bonded to four equivalent Hf4+ atoms to form a mixture of distorted corner and edge-sharing OHf4 tetrahedra.

二氧化铪（HfO₂）具有斜锆石（Baddeleyite）型晶体结构，结晶于单斜晶系P2₁/c空间群。该结构为三维骨架结构。四价铪离子（Hf⁴+）与七个二价氧离子（O²-）成键，形成由畸变共顶与共边连接方式混合构成的HfO₇五角双锥结构。铪-氧键的键长分布范围为2.05~2.26埃（Å）。体系中存在两个不等价的二价氧离子位点。在第一个氧离子位点中，二价氧离子（O²-）以畸变三角非共面的几何构型与三个等价的四价铪离子（Hf⁴+）成键。在第二个氧离子位点中，二价氧离子（O²-）与四个等价的四价铪离子（Hf⁴+）成键，形成由畸变共顶与共边连接方式混合构成的OHf₄四面体结构。