Materials Data on KCaPHO4 by Materials Project
(KCaPO4)2H2 crystallizes in the monoclinic C2/m space group. The structure is three-dimensional and consists of four hydrogen molecules and one KCaPO4 framework. In the KCaPO4 framework, K1+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of K–O bond distances ranging from 2.81–3.10 Å. Ca2+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Ca–O bond distances ranging from 2.30–2.54 Å. P4+ is bonded in a tetrahedral geometry to four O2- atoms. There are a spread of P–O bond distances ranging from 1.53–1.58 Å. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded in a 1-coordinate geometry to two equivalent K1+, two equivalent Ca2+, and one P4+ atom. In the second O2- site, O2- is bonded in a distorted single-bond geometry to four equivalent K1+ and one P4+ atom. In the third O2- site, O2- is bonded in a 1-coordinate geometry to one K1+, two equivalent Ca2+, and one P4+ atom.