Materials Data on K6NbTlAs4 by Materials Project
K6NbTlAs4 crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. there are four inequivalent K1+ sites. In the first K1+ site, K1+ is bonded in a 4-coordinate geometry to four As3- atoms. There are a spread of K–As bond distances ranging from 3.19–3.47 Å. In the second K1+ site, K1+ is bonded in a 5-coordinate geometry to five As3- atoms. There are a spread of K–As bond distances ranging from 3.28–3.61 Å. In the third K1+ site, K1+ is bonded in a 6-coordinate geometry to three As3- atoms. There are one shorter (3.50 Å) and two longer (3.56 Å) K–As bond lengths. In the fourth K1+ site, K1+ is bonded in a 5-coordinate geometry to two equivalent Tl1+ and three As3- atoms. There are one shorter (3.63 Å) and one longer (3.69 Å) K–Tl bond lengths. There are a spread of K–As bond distances ranging from 3.37–3.50 Å. Nb5+ is bonded in a tetrahedral geometry to four As3- atoms. There are a spread of Nb–As bond distances ranging from 2.49–2.56 Å. Tl1+ is bonded in a 2-coordinate geometry to four equivalent K1+ and two equivalent As3- atoms. Both Tl–As bond lengths are 2.89 Å. There are three inequivalent As3- sites. In the first As3- site, As3- is bonded in a 1-coordinate geometry to five K1+, one Nb5+, and one Tl1+ atom. In the second As3- site, As3- is bonded in a 1-coordinate geometry to six K1+ and one Nb5+ atom. In the third As3- site, As3- is bonded in a 1-coordinate geometry to seven K1+ and one Nb5+ atom.