Materials Data on Nd4Fe4As4O3F by Materials Project
Nd4Fe4As4O3F crystallizes in the tetragonal I-42m space group. The structure is three-dimensional. Nd+2.75+ is bonded in a 4-coordinate geometry to four equivalent As3-, three O2-, and one F1- atom. There are two shorter (3.25 Å) and two longer (3.33 Å) Nd–As bond lengths. There are one shorter (2.32 Å) and two longer (2.39 Å) Nd–O bond lengths. The Nd–F bond length is 2.46 Å. There are two inequivalent Fe2+ sites. In the first Fe2+ site, Fe2+ is bonded to four equivalent As3- atoms to form a mixture of edge and corner-sharing FeAs4 tetrahedra. There are two shorter (2.62 Å) and two longer (2.63 Å) Fe–As bond lengths. In the second Fe2+ site, Fe2+ is bonded to four equivalent As3- atoms to form a mixture of edge and corner-sharing FeAs4 tetrahedra. All Fe–As bond lengths are 2.62 Å. As3- is bonded in a 8-coordinate geometry to four equivalent Nd+2.75+ and four Fe2+ atoms. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded to four equivalent Nd+2.75+ atoms to form ONd4 tetrahedra that share corners with four equivalent FNd4 tetrahedra and edges with four equivalent ONd4 tetrahedra. In the second O2- site, O2- is bonded to four equivalent Nd+2.75+ atoms to form distorted ONd4 tetrahedra that share corners with four equivalent ONd4 tetrahedra, edges with two equivalent ONd4 tetrahedra, and edges with two equivalent FNd4 tetrahedra. F1- is bonded to four equivalent Nd+2.75+ atoms to form distorted FNd4 tetrahedra that share corners with four equivalent ONd4 tetrahedra and edges with four equivalent ONd4 tetrahedra.