DOI: 10.17188/1655761
title: Materials Data on K3Al5P8(H21O25)2 by Materials Project

description: K3Al5P8(H21O25)2 crystallizes in the trigonal R-3c space group. The structure is two-dimensional and consists of six K3Al5P8(H21O25)2 sheets oriented in the (0, 0, 1) direction. K is bonded in a 8-coordinate geometry to eight O atoms. There are a spread of K–O bond distances ranging from 2.72–3.13 Å. There are three inequivalent Al sites. In the first Al site, Al is bonded to six equivalent O atoms to form AlO6 octahedra that share corners with six equivalent PO4 tetrahedra. All Al–O bond lengths are 1.89 Å. In the second Al site, Al is bonded to six O atoms to form AlO6 octahedra that share corners with three equivalent PO4 tetrahedra. There is three shorter (1.86 Å) and three longer (1.96 Å) Al–O bond length. In the third Al site, Al is bonded to six O atoms to form AlO6 octahedra that share corners with three equivalent PO4 tetrahedra. There is three shorter (1.88 Å) and three longer (1.93 Å) Al–O bond length. There are two inequivalent P sites. In the first P site, P is bonded to four O atoms to form PO4 tetrahedra that share corners with three AlO6 octahedra. The corner-sharing octahedra tilt angles range from 34–41°. There are a spread of P–O bond distances ranging from 1.52–1.60 Å. In the second P site, P is bonded in a tetrahedral geometry to four O atoms. There is three shorter (1.56 Å) and one longer (1.58 Å) P–O bond length. There are seven inequivalent H sites. In the first H site, H is bonded in a single-bond geometry to one O atom. The H–O bond length is 1.00 Å. In the second H site, H is bonded in a distorted linear geometry to two O atoms. There is one shorter (1.01 Å) and one longer (1.63 Å) H–O bond length. In the third H site, H is bonded in a single-bond geometry to two O atoms. There is one shorter (1.00 Å) and one longer (1.73 Å) H–O bond length. In the fourth H site, H is bonded in a single-bond geometry to one O atom. The H–O bond length is 1.00 Å. In the fifth H site, H is bonded in a linear geometry to two O atoms. There is one shorter (1.02 Å) and one longer (1.59 Å) H–O bond length. In the sixth H site, H is bonded in a single-bond geometry to two O atoms. There is one shorter (1.01 Å) and one longer (1.74 Å) H–O bond length. In the seventh H site, H is bonded in a single-bond geometry to one O atom. The H–O bond length is 0.99 Å. There are nine inequivalent O sites. In the first O site, O is bonded in a distorted bent 150 degrees geometry to one K, one Al, and one P atom. In the second O site, O is bonded in a distorted tetrahedral geometry to one P and three equivalent H atoms. In the third O site, O is bonded in a 2-coordinate geometry to one P and three H atoms. In the fourth O site, O is bonded in a distorted trigonal non-coplanar geometry to one Al and two H atoms. In the fifth O site, O is bonded in a distorted trigonal planar geometry to one Al and two H atoms. In the sixth O site, O is bonded in a water-like geometry to two H atoms. In the seventh O site, O is bonded in a 2-coordinate geometry to one K, one Al, and one P atom. In the eighth O site, O is bonded in a bent 150 degrees geometry to one Al and one P atom. In the ninth O site, O is bonded in a distorted bent 120 degrees geometry to two equivalent K, one P, and one H atom.