DOE OSTI2020
Na2CuP2O7 crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are four inequivalent Na1+ sites. In the first Na1+ site, Na1+ is bonded to four O2- atoms to form distorted NaO4 tetrahedra that share corners with four PO4 tetrahedra and an edgeedge with one NaO4 tetrahedra. There are a spread of Na–O bond distances ranging from 2.23–2.29 Å. In the second Na1+ site, Na1+ is bonded to four O2- atoms to form distorted NaO4 tetrahedra that share corners with four PO4 tetrahedra and an edgeedge with one NaO4 tetrahedra. There are a spread of Na–O bond distances ranging from 2.24–2.29 Å. In the third Na1+ site, Na1+ is bonded to four O2- atoms to form distorted NaO4 tetrahedra that share corners with four PO4 tetrahedra and an edgeedge with one NaO4 tetrahedra. There are a spread of Na–O bond distances ranging from 2.23–2.30 Å. In the fourth Na1+ site, Na1+ is bonded to four O2- atoms to form distorted NaO4 tetrahedra that share corners with four PO4 tetrahedra and an edgeedge with one NaO4 tetrahedra. There are a spread of Na–O bond distances ranging from 2.23–2.28 Å. There are two inequivalent Cu2+ sites. In the first Cu2+ site, Cu2+ is bonded in a square co-planar geometry to four O2- atoms. There are a spread of Cu–O bond distances ranging from 1.94–2.00 Å. In the second Cu2+ site, Cu2+ is bonded in a square co-planar geometry to four O2- atoms. There are a spread of Cu–O bond distances ranging from 1.93–2.01 Å. There are four 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 PO4 tetrahedra and corners with four NaO4 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 a cornercorner with one PO4 tetrahedra and corners with four NaO4 tetrahedra. There are a spread of P–O bond distances ranging from 1.51–1.64 Å. In the third P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share a cornercorner with one PO4 tetrahedra and corners with four NaO4 tetrahedra. There are a spread of P–O bond distances ranging from 1.51–1.64 Å. In the fourth P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share a cornercorner with one PO4 tetrahedra and corners with four NaO4 tetrahedra. There are a spread of P–O bond distances ranging from 1.51–1.64 Å. There are fourteen inequivalent O2- sites. In the first O2- site, O2- is bonded in a 1-coordinate geometry to two Na1+ and one P5+ atom. In the second O2- site, O2- is bonded in a 1-coordinate geometry to two Na1+ and one P5+ atom. In the third O2- site, O2- is bonded in a 3-coordinate geometry to one Na1+, one Cu2+, and one P5+ atom. In the fourth O2- site, O2- is bonded in a 3-coordinate geometry to one Na1+, one Cu2+, and one P5+ atom. In the fifth O2- site, O2- is bonded in a distorted trigonal planar geometry to one Na1+, one Cu2+, and one P5+ atom. In the sixth O2- site, O2- is bonded in a 3-coordinate geometry to one Na1+, one Cu2+, and one P5+ atom. In the seventh O2- site, O2- is bonded in a bent 120 degrees geometry to two P5+ atoms. In the eighth O2- site, O2- is bonded in a bent 120 degrees geometry to two P5+ atoms. In the ninth O2- site, O2- is bonded in a 3-coordinate geometry to one Na1+, one Cu2+, and one P5+ atom. In the tenth O2- site, O2- is bonded in a 3-coordinate geometry to one Na1+, one Cu2+, and one P5+ atom. In the eleventh O2- site, O2- is bonded in a 3-coordinate geometry to one Na1+, one Cu2+, and one P5+ atom. In the twelfth O2- site, O2- is bonded in a 3-coordinate geometry to one Na1+, one Cu2+, and one P5+ atom. In the thirteenth O2- site, O2- is bonded in a 1-coordinate geometry to two Na1+ and one P5+ atom. In the fourteenth O2- site, O2- is bonded in a 1-coordinate geometry to two Na1+ and one P5+ atom.