Materials Data on K2EuSiSe5 by Materials Project

Abstract

K2EuSiSe5 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 8-coordinate geometry to eight Se+1.80- atoms. There are a spread of K–Se bond distances ranging from 3.27–3.90 Å. In the second K1+ site, K1+ is bonded to seven Se+1.80- atoms to form distorted KSe7 pentagonal bipyramids that share corners with two equivalent KSe7 pentagonal bipyramids, corners with four equivalent SiSe4 tetrahedra, an edgeedge with one KSe7 pentagonal bipyramid, and an edgeedge with one SiSe4 tetrahedra. There are a spread of K–Se bond distances ranging from 3.23–3.53 Å. Eu3+ is bonded in a 9-coordinate geometry to nine Se+1.80- atoms. There are a spread of Eu–Se bond distances ranging from 3.11–3.54 Å. Si4+ is bonded to four Se+1.80- atoms to form SiSe4 tetrahedra that share corners with four equivalent KSe7 pentagonal bipyramids and an edgeedge with one KSe7 pentagonal bipyramid. There are a spread of Si–Se bond distances ranging from 2.28–2.34 Å. There are five inequivalent Se+1.80- sites. In the first Se+1.80- site, Se+1.80- is bonded in a 6-coordinate geometry to three K1+, two equivalent Eu3+, and one Si4+ atom. In the second Se+1.80- site, Se+1.80- is bonded in a 1-coordinate geometry to four K1+, one Eu3+, one Si4+, and one Se+1.80- atom. The Se–Se bond length is 2.52 Å. In the third Se+1.80- site, Se+1.80- is bonded in a 1-coordinate geometry to one K1+, three equivalent Eu3+, one Si4+, and one Se+1.80- atom. The Se–Se bond length is 2.98 Å. In the fourth Se+1.80- site, Se+1.80- is bonded in a 1-coordinate geometry to six K1+ and one Si4+ atom. In the fifth Se+1.80- site, Se+1.80- is bonded in a 6-coordinate geometry to one K1+, three equivalent Eu3+, and two Se+1.80- atoms.