Materials Data on K4Ti2H2O5F8 by Materials Project
K4Ti2H2O5F8 crystallizes in the monoclinic C2/c space group. The structure is three-dimensional. there are two inequivalent K sites. In the first K site, K is bonded in a 11-coordinate geometry to one H, three O, and seven F atoms. The K–H bond length is 2.99 Å. There are a spread of K–O bond distances ranging from 2.84–2.99 Å. There are a spread of K–F bond distances ranging from 2.68–3.28 Å. In the second K site, K is bonded in a 9-coordinate geometry to one H, four O, and four F atoms. The K–H bond length is 2.93 Å. There are a spread of K–O bond distances ranging from 2.74–3.02 Å. There are a spread of K–F bond distances ranging from 2.66–2.88 Å. Ti is bonded to two O and five F atoms to form edge-sharing TiO2F5 pentagonal bipyramids. There is one shorter (1.91 Å) and one longer (1.92 Å) Ti–O bond length. There are a spread of Ti–F bond distances ranging from 1.91–2.16 Å. H is bonded in a single-bond geometry to two K and one O atom. The H–O bond length is 0.97 Å. There are three inequivalent O sites. In the first O site, O is bonded in a 1-coordinate geometry to three K, one Ti, and one O atom. The O–O bond length is 1.47 Å. In the second O site, O is bonded in a 1-coordinate geometry to three K, one Ti, and one O atom. In the third O site, O is bonded in a water-like geometry to two equivalent K and two equivalent H atoms. There are four inequivalent F sites. In the first F site, F is bonded in a 3-coordinate geometry to two equivalent K and two equivalent Ti atoms. In the second F site, F is bonded in a distorted single-bond geometry to three K and one Ti atom. In the third F site, F is bonded to three K and one Ti atom to form distorted edge-sharing FK3Ti tetrahedra. In the fourth F site, F is bonded in a distorted single-bond geometry to three K and one Ti atom.