Materials Data on KErP4(H2O9)2 by Materials Project
KErP4(H2O9)2 crystallizes in the monoclinic C2/c space group. The structure is three-dimensional. K is bonded in a distorted rectangular see-saw-like geometry to four O atoms. There are two shorter (2.65 Å) and two longer (2.98 Å) K–O bond lengths. Er is bonded in a 8-coordinate geometry to eight O atoms. There are a spread of Er–O bond distances ranging from 2.29–2.49 Å. There are two inequivalent P sites. In the first P site, P is bonded to four O atoms to form corner-sharing PO4 tetrahedra. There are a spread of P–O bond distances ranging from 1.49–1.64 Å. In the second P site, P is bonded to four O atoms to form corner-sharing PO4 tetrahedra. There are a spread of P–O bond distances ranging from 1.50–1.58 Å. There are two inequivalent H sites. In the first H site, H is bonded in a linear geometry to two O atoms. There is one shorter (1.06 Å) and one longer (1.46 Å) H–O bond length. In the second H site, H is bonded in a single-bond geometry to one O atom. The H–O bond length is 0.98 Å. There are nine inequivalent O sites. In the first O site, O is bonded in a distorted bent 150 degrees geometry to one Er and one P atom. In the second O site, O is bonded in a distorted single-bond geometry to one K and one H atom. In the third O site, O is bonded in a bent 150 degrees geometry to two P atoms. In the fourth O site, O is bonded in a distorted single-bond geometry to one Er, one H, and one O atom. The O–O bond length is 1.35 Å. In the fifth O site, O is bonded in a bent 150 degrees geometry to two P atoms. In the sixth O site, O is bonded in a bent 120 degrees geometry to one P and one H atom. In the seventh O site, O is bonded in an L-shaped geometry to one Er and one O atom. In the eighth O site, O is bonded in a single-bond geometry to one P atom. In the ninth O site, O is bonded in a 1-coordinate geometry to one K, one Er, and one P atom.