DOI: 10.17188/1285501
title: Materials Data on K2P2H2O7 by Materials Project

description: K2H2P2O7 crystallizes in the monoclinic P2_1/m space group. The structure is three-dimensional. there are four inequivalent K1+ sites. In the first K1+ site, K1+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of K–O bond distances ranging from 2.73–3.20 Å. In the second K1+ site, K1+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of K–O bond distances ranging from 2.74–3.21 Å. In the third K1+ site, K1+ is bonded to seven O2- atoms to form distorted KO7 hexagonal pyramids that share corners with eight PO4 tetrahedra. There are a spread of K–O bond distances ranging from 2.79–2.85 Å. In the fourth K1+ site, K1+ is bonded in a 7-coordinate geometry to nine O2- atoms. There are a spread of K–O bond distances ranging from 2.73–3.35 Å. There are three inequivalent P5+ sites. In the first P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share a cornercorner with one KO7 hexagonal pyramid and corners with two PO4 tetrahedra. There are a spread of P–O bond distances ranging from 1.49–1.64 Å. In the second P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share a cornercorner with one KO7 hexagonal pyramid and corners with two PO4 tetrahedra. There are a spread of P–O bond distances ranging from 1.50–1.63 Å. In the third P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with two equivalent KO7 hexagonal pyramids and corners with two PO4 tetrahedra. There are a spread of P–O bond distances ranging from 1.49–1.65 Å. There are four 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 0.99 Å. In the second 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 third 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 fourth H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.98 Å. There are twelve inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one K1+ and two equivalent P5+ atoms. In the second O2- site, O2- is bonded in a 2-coordinate geometry to one K1+ and two P5+ atoms. In the third O2- site, O2- is bonded in a distorted single-bond geometry to three K1+ and one P5+ atom. In the fourth O2- site, O2- is bonded in a distorted single-bond geometry to two K1+ and one P5+ atom. In the fifth O2- site, O2- is bonded in a distorted single-bond geometry to three K1+ and one P5+ atom. In the sixth O2- site, O2- is bonded in a distorted single-bond geometry to three K1+ and one P5+ atom. In the seventh O2- site, O2- is bonded in a bent 120 degrees geometry to one K1+ and two P5+ atoms. In the eighth O2- site, O2- is bonded in a distorted single-bond geometry to three K1+ and one P5+ atom. In the ninth O2- site, O2- is bonded in a distorted single-bond geometry to three K1+ and one P5+ atom. In the tenth O2- site, O2- is bonded in a 2-coordinate geometry to two K1+ and two equivalent P5+ atoms. In the eleventh O2- site, O2- is bonded in a water-like geometry to two K1+ and two H1+ atoms. In the twelfth O2- site, O2- is bonded in a water-like geometry to three K1+ and two H1+ atoms.