Materials Data on K2CuP2O7 by Materials Project
K2CuP2O7 crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. there are two inequivalent K1+ sites. In the first K1+ site, K1+ is bonded in a 9-coordinate geometry to nine O2- atoms. There are a spread of K–O bond distances ranging from 2.63–3.29 Å. In the second K1+ site, K1+ is bonded in a 9-coordinate geometry to nine O2- atoms. There are a spread of K–O bond distances ranging from 2.88–3.26 Å. Cu2+ is bonded to five O2- atoms to form CuO5 square pyramids that share corners with five PO4 tetrahedra. There are a spread of Cu–O bond distances ranging from 1.97–2.56 Å. There are two inequivalent P5+ sites. In the first P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with two equivalent CuO5 square pyramids and a cornercorner with one PO4 tetrahedra. There are a spread of P–O bond distances ranging from 1.51–1.64 Å. In the second P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with three equivalent CuO5 square pyramids and a cornercorner with one PO4 tetrahedra. There are a spread of P–O bond distances ranging from 1.51–1.64 Å. There are five inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted single-bond geometry to three K1+, one Cu2+, and one P5+ atom. In the second O2- site, O2- is bonded in a 1-coordinate geometry to three K1+ and one P5+ atom. In the third O2- site, O2- is bonded in a distorted bent 120 degrees geometry to three K1+, one Cu2+, and one P5+ atom. In the fourth O2- site, O2- is bonded in a bent 120 degrees geometry to two P5+ atoms. In the fifth O2- site, O2- is bonded in a 2-coordinate geometry to three K1+, one Cu2+, and one P5+ atom.