Materials Data on K4Ag18Te11 by Materials Project
K4Ag18Te11 crystallizes in the cubic Fm-3m space group. The structure is three-dimensional. there are three inequivalent K1+ sites. In the first K1+ site, K1+ is bonded in a body-centered cubic geometry to eight equivalent Te2- atoms. All K–Te bond lengths are 3.61 Å. In the second K1+ site, K1+ is bonded in a 12-coordinate geometry to four equivalent Ag1+ and eight Te2- atoms. All K–Ag bond lengths are 3.59 Å. There are four shorter (3.65 Å) and four longer (3.76 Å) K–Te bond lengths. In the third K1+ site, K1+ is bonded in a cuboctahedral geometry to twelve equivalent Te2- atoms. All K–Te bond lengths are 4.24 Å. There are two inequivalent Ag1+ sites. In the first Ag1+ site, Ag1+ is bonded in a 9-coordinate geometry to five Ag1+ and four Te2- atoms. There are four shorter (3.03 Å) and one longer (3.07 Å) Ag–Ag bond lengths. There are two shorter (2.92 Å) and two longer (3.06 Å) Ag–Te bond lengths. In the second Ag1+ site, Ag1+ is bonded in a 9-coordinate geometry to one K1+, four Ag1+, and four Te2- atoms. Both Ag–Ag bond lengths are 2.95 Å. There are a spread of Ag–Te bond distances ranging from 2.89–3.17 Å. There are three inequivalent Te2- sites. In the first Te2- site, Te2- is bonded in a cuboctahedral geometry to twelve equivalent Ag1+ atoms. In the second Te2- site, Te2- is bonded in a 10-coordinate geometry to four K1+ and six Ag1+ atoms. In the third Te2- site, Te2- is bonded in a 9-coordinate geometry to three K1+ and six Ag1+ atoms.