Materials Data on Fe12As5 by Materials Project
Fe12As5 crystallizes in the trigonal R32 space group. The structure is three-dimensional. there are four inequivalent Fe sites. In the first Fe site, Fe is bonded in a 2-coordinate geometry to ten Fe and four As atoms. There are a spread of Fe–Fe bond distances ranging from 2.47–2.87 Å. There are two shorter (2.66 Å) and two longer (2.77 Å) Fe–As bond lengths. In the second Fe site, Fe is bonded in a 4-coordinate geometry to three equivalent Fe and four As atoms. There are a spread of Fe–As bond distances ranging from 2.38–2.63 Å. In the third Fe site, Fe is bonded in a distorted trigonal non-coplanar geometry to three equivalent Fe and three equivalent As atoms. All Fe–As bond lengths are 2.35 Å. In the fourth Fe site, Fe is bonded in a trigonal bipyramidal geometry to five As atoms. There are two shorter (2.33 Å) and three longer (2.34 Å) Fe–As bond lengths. There are two inequivalent As sites. In the first As site, As is bonded in a 9-coordinate geometry to nine Fe atoms. In the second As site, As is bonded in a 10-coordinate geometry to ten Fe atoms.