Materials Data on K2Ag(AsSe2)3 by Materials Project
K2Ag(AsSe2)3 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. there are two inequivalent K1+ sites. In the first K1+ site, K1+ is bonded in a 7-coordinate geometry to seven Se2- atoms. There are a spread of K–Se bond distances ranging from 3.44–3.60 Å. In the second K1+ site, K1+ is bonded in a 8-coordinate geometry to eight Se2- atoms. There are a spread of K–Se bond distances ranging from 3.45–3.99 Å. Ag1+ is bonded to four Se2- atoms to form distorted edge-sharing AgSe4 tetrahedra. There are a spread of Ag–Se bond distances ranging from 2.66–2.84 Å. There are three inequivalent As3+ sites. In the first As3+ site, As3+ is bonded in a distorted trigonal non-coplanar geometry to three Se2- atoms. There are one shorter (2.41 Å) and two longer (2.46 Å) As–Se bond lengths. In the second As3+ site, As3+ is bonded in a trigonal non-coplanar geometry to three Se2- atoms. There are a spread of As–Se bond distances ranging from 2.38–2.51 Å. In the third As3+ site, As3+ is bonded in a trigonal non-coplanar geometry to three Se2- atoms. There are a spread of As–Se bond distances ranging from 2.36–2.50 Å. There are six inequivalent Se2- sites. In the first Se2- site, Se2- is bonded in a distorted rectangular see-saw-like geometry to two K1+ and two As3+ atoms. In the second Se2- site, Se2- is bonded in a 5-coordinate geometry to three K1+, one Ag1+, and one As3+ atom. In the third Se2- site, Se2- is bonded to three K1+ and two As3+ atoms to form distorted SeK3As2 square pyramids that share corners with two equivalent SeK3As2 square pyramids, a cornercorner with one SeK2As2 trigonal pyramid, and an edgeedge with one SeK2As2 trigonal pyramid. In the fourth Se2- site, Se2- is bonded in a 4-coordinate geometry to two K1+, one Ag1+, and one As3+ atom. In the fifth Se2- site, Se2- is bonded to two equivalent K1+ and two As3+ atoms to form distorted SeK2As2 trigonal pyramids that share a cornercorner with one SeK3As2 square pyramid, corners with two equivalent SeK2As2 trigonal pyramids, and an edgeedge with one SeK3As2 square pyramid. In the sixth Se2- site, Se2- is bonded in a 5-coordinate geometry to three K1+, two equivalent Ag1+, and one As3+ atom.