Materials Data on K3NaP2O11 by Materials Project
K3NaP2O11 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. there are three inequivalent K sites. In the first K site, K is bonded to five O atoms to form distorted KO5 square pyramids that share corners with two equivalent KO5 square pyramids, corners with two equivalent NaO5 square pyramids, corners with two PO4 tetrahedra, and an edgeedge with one NaO5 square pyramid. There are a spread of K–O bond distances ranging from 2.70–2.96 Å. In the second K site, K is bonded in a 7-coordinate geometry to eight O atoms. There are a spread of K–O bond distances ranging from 2.65–3.17 Å. In the third K site, K is bonded in a 8-coordinate geometry to eight O atoms. There are a spread of K–O bond distances ranging from 2.59–3.00 Å. Na is bonded to five O atoms to form distorted NaO5 square pyramids that share corners with two equivalent KO5 square pyramids, corners with four PO4 tetrahedra, and an edgeedge with one KO5 square pyramid. There are a spread of Na–O bond distances ranging from 2.27–2.58 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 a cornercorner with one KO5 square pyramid, 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 1.52–1.66 Å. In the second P site, P is bonded to four O atoms to form PO4 tetrahedra that share a cornercorner with one KO5 square pyramid, 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 1.53–1.67 Å. There are eleven inequivalent O sites. In the first O site, O is bonded in a 1-coordinate geometry to one K, one Na, and one P atom. In the second O site, O is bonded in a 3-coordinate geometry to three K atoms. In the third O site, O is bonded in a 2-coordinate geometry to one K and two P atoms. In the fourth O site, O is bonded in a 4-coordinate geometry to two K, one Na, and one P atom. In the fifth O site, O is bonded in a 1-coordinate geometry to one K, one Na, and one P atom. In the sixth O site, O is bonded in a 4-coordinate geometry to three K and one O atom. The O–O bond length is 1.25 Å. In the seventh O site, O is bonded in a single-bond geometry to one P atom. In the eighth O site, O is bonded in a T-shaped geometry to two equivalent K and one Na atom. In the ninth O site, O is bonded in a distorted single-bond geometry to three K and one P atom. In the tenth O site, O is bonded in a 4-coordinate geometry to three K and one O atom. In the eleventh O site, O is bonded in a 4-coordinate geometry to two K, one Na, and one P atom.