Materials Data on KCrPO4F by Materials Project
KCrPO4F crystallizes in the orthorhombic Pna2_1 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 seven O2- and two F1- atoms. There are a spread of K–O bond distances ranging from 2.69–3.13 Å. There are one shorter (2.70 Å) and one longer (3.14 Å) K–F bond lengths. In the second K1+ site, K1+ is bonded in a 7-coordinate geometry to five O2- and two F1- atoms. There are a spread of K–O bond distances ranging from 2.70–2.92 Å. There are one shorter (2.67 Å) and one longer (3.02 Å) K–F bond lengths. There are two inequivalent Cr3+ sites. In the first Cr3+ site, Cr3+ is bonded to four O2- and two F1- atoms to form CrO4F2 octahedra that share corners with two equivalent CrO4F2 octahedra and corners with four PO4 tetrahedra. The corner-sharing octahedra tilt angles range from 52–53°. There are a spread of Cr–O bond distances ranging from 1.96–2.03 Å. There are one shorter (2.00 Å) and one longer (2.01 Å) Cr–F bond lengths. In the second Cr3+ site, Cr3+ is bonded to four O2- and two F1- atoms to form CrO4F2 octahedra that share corners with two equivalent CrO4F2 octahedra and corners with four PO4 tetrahedra. The corner-sharing octahedra tilt angles range from 52–53°. There are a spread of Cr–O bond distances ranging from 1.99–2.05 Å. There is one shorter (1.98 Å) and one longer (1.99 Å) Cr–F bond length. 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 four CrO4F2 octahedra. The corner-sharing octahedra tilt angles range from 45–49°. There are a spread of P–O bond distances ranging from 1.54–1.56 Å. In the second P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with four CrO4F2 octahedra. The corner-sharing octahedra tilt angles range from 42–48°. There is one shorter (1.54 Å) and three longer (1.56 Å) P–O bond length. There are eight inequivalent O2- sites. In the first O2- site, O2- is bonded in a 2-coordinate geometry to two K1+, one Cr3+, and one P5+ atom. In the second O2- site, O2- is bonded in a 2-coordinate geometry to one K1+, one Cr3+, and one P5+ atom. In the third O2- site, O2- is bonded in a 2-coordinate geometry to two K1+, one Cr3+, and one P5+ atom. In the fourth O2- site, O2- is bonded in a 2-coordinate geometry to two K1+, one Cr3+, and one P5+ atom. In the fifth O2- site, O2- is bonded in a 2-coordinate geometry to one K1+, one Cr3+, and one P5+ atom. In the sixth O2- site, O2- is bonded in a 2-coordinate geometry to two K1+, one Cr3+, and one P5+ atom. In the seventh O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Cr3+ and one P5+ atom. In the eighth O2- site, O2- is bonded in a 2-coordinate geometry to two K1+, one Cr3+, and one P5+ atom. There are two inequivalent F1- sites. In the first F1- site, F1- is bonded in a 2-coordinate geometry to two K1+ and two Cr3+ atoms. In the second F1- site, F1- is bonded in a 2-coordinate geometry to two K1+ and two Cr3+ atoms.