Materials Data on KBa2(FeAs)6 by Materials Project

KBa2(FeAs)6 is alpha bismuth trifluoride-derived structured and crystallizes in the monoclinic C2/m space group. The structure is three-dimensional. K1+ is bonded in a body-centered cubic geometry to eight As3- atoms. There are four shorter (3.39 Å) and four longer (3.43 Å) K–As bond lengths. Ba2+ is bonded in a body-centered cubic geometry to eight As3- atoms. There are a spread of Ba–As bond distances ranging from 3.35–3.49 Å. There are two inequivalent Fe+2.17+ sites. In the first Fe+2.17+ site, Fe+2.17+ is bonded to four As3- atoms to form a mixture of edge and corner-sharing FeAs4 tetrahedra. There are two shorter (2.32 Å) and two longer (2.33 Å) Fe–As bond lengths. In the second Fe+2.17+ site, Fe+2.17+ is bonded to four As3- atoms to form a mixture of edge and corner-sharing FeAs4 tetrahedra. There are two shorter (2.34 Å) and two longer (2.35 Å) Fe–As bond lengths. There are three inequivalent As3- sites. In the first As3- site, As3- is bonded in a 8-coordinate geometry to one K1+, three equivalent Ba2+, and four equivalent Fe+2.17+ atoms. In the second As3- site, As3- is bonded in a 8-coordinate geometry to one K1+, three equivalent Ba2+, and four Fe+2.17+ atoms. In the third As3- site, As3- is bonded in a 8-coordinate geometry to two equivalent K1+, two equivalent Ba2+, and four Fe+2.17+ atoms.