Materials Data on K3Ta2AsSe11 by Materials Project
K3Ta2AsSe11 crystallizes in the monoclinic Cc space group. The structure is three-dimensional. there are three inequivalent K1+ sites. In the first K1+ site, K1+ is bonded in a 9-coordinate geometry to nine Se+1.45- atoms. There are a spread of K–Se bond distances ranging from 3.39–3.72 Å. In the second K1+ site, K1+ is bonded in a 10-coordinate geometry to ten Se+1.45- atoms. There are a spread of K–Se bond distances ranging from 3.45–4.04 Å. In the third K1+ site, K1+ is bonded in a 10-coordinate geometry to ten Se+1.45- atoms. There are a spread of K–Se bond distances ranging from 3.32–4.07 Å. There are two inequivalent Ta5+ sites. In the first Ta5+ site, Ta5+ is bonded to seven Se+1.45- atoms to form distorted face-sharing TaSe7 pentagonal bipyramids. There are a spread of Ta–Se bond distances ranging from 2.37–2.93 Å. In the second Ta5+ site, Ta5+ is bonded to seven Se+1.45- atoms to form distorted face-sharing TaSe7 pentagonal bipyramids. There are a spread of Ta–Se bond distances ranging from 2.37–2.88 Å. As3+ is bonded in a distorted trigonal non-coplanar geometry to three Se+1.45- atoms. There are a spread of As–Se bond distances ranging from 2.41–2.48 Å. There are eleven inequivalent Se+1.45- sites. In the first Se+1.45- site, Se+1.45- is bonded in a 1-coordinate geometry to two K1+, one Ta5+, and one Se+1.45- atom. The Se–Se bond length is 2.39 Å. In the second Se+1.45- site, Se+1.45- is bonded in a distorted L-shaped geometry to three K1+, one Ta5+, and one As3+ atom. In the third Se+1.45- site, Se+1.45- is bonded in a 2-coordinate geometry to four K1+ and two Ta5+ atoms. In the fourth Se+1.45- site, Se+1.45- is bonded in a 1-coordinate geometry to three K1+ and one Ta5+ atom. In the fifth Se+1.45- site, Se+1.45- is bonded in a 4-coordinate geometry to two equivalent K1+, one Ta5+, and one As3+ atom. In the sixth Se+1.45- site, Se+1.45- is bonded in a 2-coordinate geometry to two K1+, one Ta5+, and one Se+1.45- atom. The Se–Se bond length is 2.41 Å. In the seventh Se+1.45- site, Se+1.45- is bonded in a 2-coordinate geometry to two K1+, two Ta5+, and one Se+1.45- atom. In the eighth Se+1.45- site, Se+1.45- is bonded in a 1-coordinate geometry to four K1+ and one Ta5+ atom. In the ninth Se+1.45- site, Se+1.45- is bonded in an L-shaped geometry to one K1+, one Ta5+, and one As3+ atom. In the tenth Se+1.45- site, Se+1.45- is bonded in a distorted single-bond geometry to four K1+ and one Ta5+ atom. In the eleventh Se+1.45- site, Se+1.45- is bonded in a 2-coordinate geometry to two K1+, two Ta5+, and one Se+1.45- atom.