DOE OSTI2020
Fe3P8(H9O16)2NH4O2(H2O)2 crystallizes in the monoclinic C2/c space group. The structure is two-dimensional and consists of four dihydroxyazanium molecules; eight water molecules; and two Fe3P8(H9O16)2 sheets oriented in the (0, 0, 1) direction. In each Fe3P8(H9O16)2 sheet, there are two inequivalent Fe3+ sites. In the first Fe3+ site, Fe3+ is bonded to six O2- atoms to form FeO6 octahedra that share corners with four PO4 tetrahedra. There are a spread of Fe–O bond distances ranging from 1.92–2.43 Å. In the second Fe3+ site, Fe3+ is bonded to six O2- atoms to form FeO6 octahedra that share corners with four PO4 tetrahedra. There are a spread of Fe–O bond distances ranging from 2.00–2.11 Å. There are four inequivalent P5+ sites. In the first P5+ site, P5+ is bonded in a trigonal non-coplanar geometry to three O2- atoms. There are a spread of P–O bond distances ranging from 1.58–1.68 Å. In the second P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with two FeO6 octahedra. The corner-sharing octahedra tilt angles range from 28–32°. There are a spread of P–O bond distances ranging from 1.51–1.69 Å. In the third P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with two equivalent FeO6 octahedra. The corner-sharing octahedra tilt angles range from 23–40°. There are a spread of P–O bond distances ranging from 1.51–1.59 Å. In the fourth P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with two FeO6 octahedra. The corner-sharing octahedra tilt angles range from 26–40°. There are a spread of P–O bond distances ranging from 1.51–1.63 Å. There are nine inequivalent H1+ sites. In the first H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 1.00 Å. In the second H1+ site, H1+ is bonded in a linear geometry to two O2- atoms. There is one shorter (1.09 Å) and one longer (1.39 Å) H–O bond length. In the third H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 1.01 Å. In the fourth H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.98 Å. In the fifth H1+ site, H1+ is bonded in a linear geometry to two O2- atoms. There is one shorter (1.03 Å) and one longer (1.57 Å) H–O bond length. In the sixth H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 1.00 Å. In the seventh H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 1.02 Å. In the eighth H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.98 Å. In the ninth H1+ site, H1+ is bonded in a linear geometry to two O2- atoms. There is one shorter (1.15 Å) and one longer (1.28 Å) H–O bond length. There are sixteen inequivalent O2- sites. In the first O2- site, O2- is bonded in a 1-coordinate geometry to one Fe3+, one P5+, and one H1+ atom. In the second O2- site, O2- is bonded in a 1-coordinate geometry to one Fe3+, one P5+, and one H1+ atom. In the third O2- site, O2- is bonded in a 3-coordinate geometry to one Fe3+, one P5+, and one H1+ atom. In the fourth O2- site, O2- is bonded in a bent 150 degrees geometry to one Fe3+ and one P5+ atom. In the fifth O2- site, O2- is bonded in a bent 150 degrees geometry to one Fe3+ and one P5+ atom. In the sixth O2- site, O2- is bonded in a bent 120 degrees geometry to one P5+ and one H1+ atom. In the seventh O2- site, O2- is bonded in a trigonal planar geometry to one P5+ and two H1+ atoms. In the eighth O2- site, O2- is bonded in a bent 150 degrees geometry to one Fe3+ and one P5+ atom. In the ninth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Fe3+ and one P5+ atom. In the tenth O2- site, O2- is bonded in a bent 120 degrees geometry to one P5+ and one H1+ atom. In the eleventh O2- site, O2- is bonded in a bent 120 degrees geometry to one P5+ and one H1+ atom. In the twelfth O2- site, O2- is bonded in a bent 150 degrees geometry to one Fe3+ and one P5+ atom. In the thirteenth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Fe3+ and one P5+ atom. In the fourteenth O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one P5+ and one H1+ atom. In the fifteenth O2- site, O2- is bonded in a distorted single-bond geometry to one P5+ atom. In the sixteenth O2- site, O2- is bonded in a distorted trigonal non-coplanar geometry to three H1+ atoms.