Materials Data on KCo3Cu(AsO4)3 by Materials Project
KCo3Cu(AsO4)3 crystallizes in the monoclinic C2/c space group. The structure is three-dimensional. K1+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of K–O bond distances ranging from 2.67–3.00 Å. There are two inequivalent Co2+ sites. In the first Co2+ site, Co2+ is bonded to six O2- atoms to form CoO6 octahedra that share corners with six AsO4 tetrahedra, an edgeedge with one CoO6 octahedra, and an edgeedge with one CoO6 pentagonal pyramid. There are a spread of Co–O bond distances ranging from 2.03–2.18 Å. In the second Co2+ site, Co2+ is bonded to six O2- atoms to form distorted CoO6 pentagonal pyramids that share corners with six AsO4 tetrahedra and edges with two equivalent CoO6 octahedra. There are a spread of Co–O bond distances ranging from 2.10–2.21 Å. Cu2+ is bonded in a square co-planar geometry to four O2- atoms. There is two shorter (1.95 Å) and two longer (1.97 Å) Cu–O bond length. There are two inequivalent As5+ sites. In the first As5+ site, As5+ is bonded to four O2- atoms to form AsO4 tetrahedra that share corners with four equivalent CoO6 octahedra and corners with two equivalent CoO6 pentagonal pyramids. The corner-sharing octahedra tilt angles range from 38–61°. There are a spread of As–O bond distances ranging from 1.71–1.75 Å. In the second As5+ site, As5+ is bonded to four O2- atoms to form AsO4 tetrahedra that share corners with four equivalent CoO6 octahedra and corners with two equivalent CoO6 pentagonal pyramids. The corner-sharing octahedra tilt angles range from 60–62°. There is two shorter (1.73 Å) and two longer (1.75 Å) As–O bond length. There are six inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted trigonal planar geometry to one Co2+, one Cu2+, and one As5+ atom. In the second O2- site, O2- is bonded in a distorted trigonal planar geometry to two equivalent Co2+ and one As5+ atom. In the third O2- site, O2- is bonded in a 3-coordinate geometry to one K1+, two Co2+, and one As5+ atom. In the fourth O2- site, O2- is bonded in a 3-coordinate geometry to one K1+, two Co2+, and one As5+ atom. In the fifth O2- site, O2- is bonded in a distorted trigonal planar geometry to one Co2+, one Cu2+, and one As5+ atom. In the sixth O2- site, O2- is bonded in a 4-coordinate geometry to two equivalent K1+, one Co2+, and one As5+ atom.