DOI: 10.17188/1200122
title: Materials Data on MgAl2P2(HO)18 by Materials Project

description: MgAl2P2(HO)18 crystallizes in the triclinic P-1 space group. The structure is three-dimensional. Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with two equivalent PO4 tetrahedra. There are a spread of Mg–O bond distances ranging from 2.06–2.13 Å. There are two inequivalent Al3+ sites. In the first Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with two equivalent AlO6 octahedra and corners with four equivalent PO4 tetrahedra. The corner-sharing octahedral tilt angles are 44°. There are a spread of Al–O bond distances ranging from 1.89–1.95 Å. In the second Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with two equivalent AlO6 octahedra and corners with two equivalent PO4 tetrahedra. The corner-sharing octahedral tilt angles are 44°. There are a spread of Al–O bond distances ranging from 1.87–2.00 Å. P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share a cornercorner with one MgO6 octahedra and corners with three AlO6 octahedra. The corner-sharing octahedra tilt angles range from 41–51°. There is two shorter (1.55 Å) and two longer (1.56 Å) P–O bond length. There are nine inequivalent H1+ sites. In the first H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.98 Å. In the second H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 1.00 Å. In the third H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.99 Å. In the fourth H1+ site, H1+ is bonded in a single-bond geometry to two O2- atoms. There is one shorter (1.00 Å) and one longer (1.71 Å) H–O bond length. In the fifth H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.99 Å. In the sixth H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.98 Å. In the seventh H1+ site, H1+ is bonded in a distorted single-bond geometry to two O2- atoms. There is one shorter (1.01 Å) and one longer (1.62 Å) H–O bond length. In the eighth H1+ site, H1+ is bonded in a distorted single-bond geometry to two O2- atoms. There is one shorter (1.01 Å) and one longer (1.65 Å) H–O bond length. In the ninth H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.99 Å. There are nine inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted water-like geometry to one Mg2+ and two H1+ atoms. In the second O2- site, O2- is bonded in a distorted water-like geometry to one Mg2+ and two H1+ atoms. In the third O2- site, O2- is bonded in a distorted water-like geometry to three H1+ atoms. In the fourth O2- site, O2- is bonded in a distorted water-like geometry to one Al3+ and two H1+ atoms. In the fifth O2- site, O2- is bonded in a 1-coordinate geometry to two Al3+ and one H1+ atom. In the sixth O2- site, O2- is bonded in a distorted trigonal planar geometry to one Al3+, one P5+, and one H1+ atom. In the seventh O2- site, O2- is bonded in a 1-coordinate geometry to one Mg2+ and one P5+ atom. In the eighth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Al3+ and one P5+ atom. In the ninth O2- site, O2- is bonded in a distorted trigonal non-coplanar geometry to one Al3+, one P5+, and one H1+ atom.