Materials Data on K7(FeTe2)4 by Materials Project
K7(FeTe2)4 crystallizes in the tetragonal P4_2/nmc space group. The structure is three-dimensional. there are three inequivalent K1+ sites. In the first K1+ site, K1+ is bonded in a 8-coordinate geometry to eight Te2- atoms. There are four shorter (3.59 Å) and four longer (3.82 Å) K–Te bond lengths. In the second K1+ site, K1+ is bonded to four equivalent Te2- atoms to form KTe4 tetrahedra that share corners with four equivalent FeTe4 tetrahedra and edges with two equivalent KTe4 tetrahedra. There are two shorter (3.50 Å) and two longer (3.56 Å) K–Te bond lengths. In the third K1+ site, K1+ is bonded in a 8-coordinate geometry to eight Te2- atoms. There are a spread of K–Te bond distances ranging from 3.51–4.16 Å. Fe+2.25+ is bonded to four Te2- atoms to form FeTe4 tetrahedra that share corners with two equivalent KTe4 tetrahedra and edges with three equivalent FeTe4 tetrahedra. There are a spread of Fe–Te bond distances ranging from 2.59–2.63 Å. There are two inequivalent Te2- sites. In the first Te2- site, Te2- is bonded in a 6-coordinate geometry to five K1+ and three equivalent Fe+2.25+ atoms. In the second Te2- site, Te2- is bonded in a 8-coordinate geometry to seven K1+ and one Fe+2.25+ atom.