DOE OSTI2020
La3YFe4(AsO)4 crystallizes in the orthorhombic Pmm2 space group. The structure is three-dimensional. there are two inequivalent La3+ sites. In the first La3+ site, La3+ is bonded in a 4-coordinate geometry to four equivalent As3- and four O2- atoms. All La–As bond lengths are 3.40 Å. There are two shorter (2.38 Å) and two longer (2.41 Å) La–O bond lengths. In the second La3+ site, La3+ is bonded in a 4-coordinate geometry to four As3- and four O2- atoms. There are two shorter (3.40 Å) and two longer (3.43 Å) La–As bond lengths. There are three shorter (2.38 Å) and one longer (2.39 Å) La–O bond lengths. Y3+ is bonded in a 4-coordinate geometry to four equivalent As3- and four O2- atoms. All Y–As bond lengths are 3.46 Å. There are two shorter (2.25 Å) and two longer (2.28 Å) Y–O bond lengths. There are three inequivalent Fe2+ sites. In the first Fe2+ site, Fe2+ is bonded to four 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 As3- atoms to form a mixture of edge and corner-sharing FeAs4 tetrahedra. There are two shorter (2.60 Å) and two longer (2.63 Å) Fe–As bond lengths. In the third Fe2+ site, Fe2+ is bonded to four 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. There are three inequivalent As3- sites. In the first As3- site, As3- is bonded in a 8-coordinate geometry to four equivalent La3+ and four Fe2+ atoms. In the second As3- site, As3- is bonded in a 8-coordinate geometry to four equivalent La3+ and four Fe2+ atoms. In the third As3- site, As3- is bonded in a 8-coordinate geometry to two equivalent La3+, two equivalent Y3+, and four Fe2+ atoms. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded to three La3+ and one Y3+ atom to form OLa3Y tetrahedra that share corners with four equivalent OLa3Y tetrahedra and edges with four OLa2Y2 tetrahedra. In the second O2- site, O2- is bonded to two equivalent La3+ and two equivalent Y3+ atoms to form OLa2Y2 tetrahedra that share corners with four OLa2Y2 tetrahedra and edges with four equivalent OLa3Y tetrahedra. In the third O2- site, O2- is bonded to four La3+ atoms to form OLa4 tetrahedra that share corners with four OLa2Y2 tetrahedra and edges with four equivalent OLa3Y tetrahedra.