Materials Data on FeAsNO4F by Materials Project
(Fe2As2O7F2)2N2(NO)2 crystallizes in the orthorhombic Pna2_1 space group. The structure is three-dimensional and consists of four ammonia molecules, four nitroxyl molecules, and one Fe2As2O7F2 framework. In the Fe2As2O7F2 framework, there are two inequivalent Fe3+ sites. In the first Fe3+ site, Fe3+ is bonded to three O2- and two F1- atoms to form FeO3F2 trigonal bipyramids that share corners with two equivalent FeO4F2 octahedra and corners with two equivalent AsO4 tetrahedra. The corner-sharing octahedra tilt angles range from 41–49°. There are a spread of Fe–O bond distances ranging from 1.91–2.03 Å. There is one shorter (1.91 Å) and one longer (1.98 Å) Fe–F bond length. In the second Fe3+ site, Fe3+ is bonded to four O2- and two F1- atoms to form FeO4F2 octahedra that share corners with two equivalent AsO4 tetrahedra and corners with two equivalent FeO3F2 trigonal bipyramids. There are a spread of Fe–O bond distances ranging from 1.96–2.09 Å. There is one shorter (1.97 Å) and one longer (2.01 Å) Fe–F bond length. There are two inequivalent As5+ sites. In the first As5+ site, As5+ is bonded to four O2- atoms to form AsO4 tetrahedra that share corners with two equivalent FeO4F2 octahedra and corners with two equivalent FeO3F2 trigonal bipyramids. The corner-sharing octahedra tilt angles range from 48–51°. There is three shorter (1.72 Å) and one longer (1.73 Å) As–O bond length. In the second As5+ site, As5+ is bonded in a distorted trigonal planar geometry to three O2- atoms. There are a spread of As–O bond distances ranging from 1.67–1.69 Å. There are seven inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Fe3+ and one As5+ atom. In the second O2- site, O2- is bonded in a bent 120 degrees geometry to one Fe3+ and one As5+ atom. In the third O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Fe3+ and one As5+ atom. In the fourth O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Fe3+ and one As5+ atom. In the fifth O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Fe3+ and one As5+ atom. In the sixth O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Fe3+ and one As5+ atom. In the seventh O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Fe3+ and one As5+ atom. There are two inequivalent F1- sites. In the first F1- site, F1- is bonded in a distorted bent 120 degrees geometry to two Fe3+ atoms. In the second F1- site, F1- is bonded in a distorted bent 150 degrees geometry to two Fe3+ atoms.