Materials Data on KBa3(FeAs)8 by Materials Project
KBa3(FeAs)8 crystallizes in the triclinic P-1 space group. The structure is three-dimensional. K1+ is bonded in a square co-planar geometry to four As3- atoms. There are two shorter (2.86 Å) and two longer (2.87 Å) K–As bond lengths. There are two inequivalent Ba2+ sites. In the first Ba2+ site, Ba2+ is bonded in a rectangular see-saw-like geometry to four As3- atoms. There are a spread of Ba–As bond distances ranging from 2.79–2.89 Å. In the second Ba2+ site, Ba2+ is bonded in a square co-planar geometry to four As3- atoms. All Ba–As bond lengths are 2.87 Å. There are four inequivalent Fe+2.12+ sites. In the first Fe+2.12+ site, Fe+2.12+ is bonded in a 4-coordinate geometry to two Fe+2.12+ and two As3- atoms. Both Fe–Fe bond lengths are 1.97 Å. There are one shorter (2.07 Å) and one longer (2.68 Å) Fe–As bond lengths. In the second Fe+2.12+ site, Fe+2.12+ is bonded in a 4-coordinate geometry to two Fe+2.12+ and two As3- atoms. There is one shorter (1.96 Å) and one longer (1.97 Å) Fe–Fe bond length. There are one shorter (2.05 Å) and one longer (2.66 Å) Fe–As bond lengths. In the third Fe+2.12+ site, Fe+2.12+ is bonded in a 4-coordinate geometry to two Fe+2.12+ and two As3- atoms. The Fe–Fe bond length is 1.96 Å. There are one shorter (2.04 Å) and one longer (2.71 Å) Fe–As bond lengths. In the fourth Fe+2.12+ site, Fe+2.12+ is bonded in a 4-coordinate geometry to two Fe+2.12+ and two As3- atoms. There are one shorter (2.04 Å) and one longer (2.71 Å) Fe–As bond lengths. There are four inequivalent As3- sites. In the first As3- site, As3- is bonded in a 4-coordinate geometry to one K1+, one Ba2+, and two Fe+2.12+ atoms. In the second As3- site, As3- is bonded in a 4-coordinate geometry to two Ba2+ and two Fe+2.12+ atoms. In the third As3- site, As3- is bonded in a 4-coordinate geometry to one K1+, one Ba2+, and two Fe+2.12+ atoms. In the fourth As3- site, As3- is bonded in a 4-coordinate geometry to two Ba2+ and two Fe+2.12+ atoms.