Materials Data on Na2P2O7 by Materials Project
Na2P2O7 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. there are two inequivalent Na sites. In the first Na site, Na is bonded to five O atoms to form NaO5 square pyramids that share corners with five PO4 tetrahedra and an edgeedge with one NaO5 square pyramid. There are a spread of Na–O bond distances ranging from 2.32–2.45 Å. In the second Na site, Na is bonded in a 6-coordinate geometry to six O atoms. There are a spread of Na–O bond distances ranging from 2.33–2.67 Å. 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 equivalent NaO5 square pyramids and a cornercorner with one PO4 tetrahedra. There are a spread of P–O bond distances ranging from 1.52–1.62 Å. In the second P site, P is bonded to four O atoms to form PO4 tetrahedra that share corners with two equivalent NaO5 square pyramids and a cornercorner with one PO4 tetrahedra. There are a spread of P–O bond distances ranging from 1.52–1.63 Å. There are seven inequivalent O sites. In the first O site, O is bonded in a 3-coordinate geometry to two Na and one P atom. In the second O site, O is bonded in a 3-coordinate geometry to two Na and one P atom. In the third O site, O is bonded in a bent 150 degrees geometry to one Na and one P atom. In the fourth O site, O is bonded in a bent 150 degrees geometry to one Na and one P atom. In the fifth O site, O is bonded in a distorted linear geometry to one Na and one P atom. In the sixth O site, O is bonded in a distorted rectangular see-saw-like geometry to three Na and one P atom. In the seventh O site, O is bonded in a 2-coordinate geometry to one Na and two P atoms.