Materials Data on KCu4AsS4 by Materials Project
KCu4AsS4 crystallizes in the monoclinic P2_1 space group. The structure is three-dimensional. K1+ is bonded in a 7-coordinate geometry to seven S2- atoms. There are a spread of K–S bond distances ranging from 3.15–3.62 Å. There are four inequivalent Cu1+ sites. In the first Cu1+ site, Cu1+ is bonded in a linear geometry to two equivalent S2- atoms. Both Cu–S bond lengths are 2.21 Å. In the second Cu1+ site, Cu1+ is bonded in a 3-coordinate geometry to four S2- atoms. There are a spread of Cu–S bond distances ranging from 2.31–3.00 Å. In the third Cu1+ site, Cu1+ is bonded in a distorted trigonal planar geometry to three S2- atoms. There are one shorter (2.28 Å) and two longer (2.30 Å) Cu–S bond lengths. In the fourth Cu1+ site, Cu1+ is bonded to four S2- atoms to form corner-sharing CuS4 tetrahedra. There are a spread of Cu–S bond distances ranging from 2.29–2.45 Å. As3+ is bonded in a distorted trigonal non-coplanar geometry to three S2- atoms. There are a spread of As–S bond distances ranging from 2.27–2.34 Å. There are four inequivalent S2- sites. In the first S2- site, S2- is bonded in a 6-coordinate geometry to one K1+ and five Cu1+ atoms. In the second S2- site, S2- is bonded in a 3-coordinate geometry to three equivalent K1+, two equivalent Cu1+, and one As3+ atom. In the third S2- site, S2- is bonded in a 6-coordinate geometry to two equivalent K1+, three Cu1+, and one As3+ atom. In the fourth S2- site, S2- is bonded in a 5-coordinate geometry to one K1+, three Cu1+, and one As3+ atom.