Materials Data on KCuPO4 by Materials Project
KCuPO4 crystallizes in the monoclinic P2_1 space group. The structure is three-dimensional. there are two inequivalent K1+ sites. In the first K1+ site, K1+ is bonded in a 5-coordinate geometry to five O2- atoms. There are a spread of K–O bond distances ranging from 2.71–2.91 Å. In the second K1+ site, K1+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of K–O bond distances ranging from 2.69–3.20 Å. There are two inequivalent Cu2+ sites. In the first Cu2+ site, Cu2+ is bonded in a distorted rectangular see-saw-like geometry to four O2- atoms. There are a spread of Cu–O bond distances ranging from 1.93–2.02 Å. In the second Cu2+ site, Cu2+ is bonded to five O2- atoms to form distorted CuO5 trigonal bipyramids that share corners with three PO4 tetrahedra and an edgeedge with one PO4 tetrahedra. There are a spread of Cu–O bond distances ranging from 1.93–2.37 Å. There are two 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 CuO5 trigonal bipyramid. There is one shorter (1.55 Å) and three longer (1.56 Å) P–O bond length. In the second P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with two equivalent CuO5 trigonal bipyramids and an edgeedge with one CuO5 trigonal bipyramid. There are a spread of P–O bond distances ranging from 1.52–1.62 Å. There are eight inequivalent O2- sites. In the first O2- site, O2- is bonded in a 2-coordinate geometry to one K1+, one Cu2+, and one P5+ atom. In the second O2- site, O2- is bonded in a 4-coordinate geometry to two K1+, one Cu2+, and one P5+ atom. In the third O2- site, O2- is bonded in a 4-coordinate geometry to two K1+, one Cu2+, and one P5+ atom. In the fourth O2- site, O2- is bonded in a 4-coordinate geometry to two K1+, one Cu2+, and one P5+ atom. In the fifth O2- site, O2- is bonded in a 2-coordinate geometry to one K1+, one Cu2+, and one P5+ atom. In the sixth O2- site, O2- is bonded in a 2-coordinate geometry to two equivalent K1+, one Cu2+, and one P5+ atom. In the seventh O2- site, O2- is bonded in a distorted single-bond geometry to two K1+, one Cu2+, and one P5+ atom. In the eighth O2- site, O2- is bonded in a 3-coordinate geometry to one K1+, two Cu2+, and one P5+ atom.