Materials Data on HfO3F4 by Materials Project
(Hf(OF2)2)2O2 crystallizes in the monoclinic P2_1/c space group. The structure is one-dimensional and consists of four water molecules and two Hf(OF2)2 ribbons oriented in the (1, 0, 0) direction. In each Hf(OF2)2 ribbon, Hf is bonded in a 8-coordinate geometry to two O and six F atoms. There are one shorter (2.27 Å) and one longer (2.33 Å) Hf–O bond lengths. There are a spread of Hf–F bond distances ranging from 1.95–2.19 Å. There are two inequivalent O sites. In the first O site, O is bonded in a single-bond geometry to one Hf atom. In the second O site, O is bonded in a single-bond geometry to one Hf atom. There are four inequivalent F sites. In the first F site, F is bonded in a water-like geometry to two equivalent Hf atoms. In the second F site, F is bonded in a water-like geometry to two equivalent Hf atoms. In the third F site, F is bonded in a single-bond geometry to one Hf atom. In the fourth F site, F is bonded in a single-bond geometry to one Hf atom.