DOE OSTI2020
UP2O7 crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are four inequivalent U4+ sites. In the first U4+ site, U4+ is bonded to six O2- atoms to form UO6 octahedra that share corners with six PO4 tetrahedra. There are a spread of U–O bond distances ranging from 2.23–2.29 Å. In the second U4+ site, U4+ is bonded to six O2- atoms to form UO6 octahedra that share corners with six PO4 tetrahedra. There are a spread of U–O bond distances ranging from 2.22–2.26 Å. In the third U4+ site, U4+ is bonded to six O2- atoms to form UO6 octahedra that share corners with six PO4 tetrahedra. There are a spread of U–O bond distances ranging from 2.21–2.28 Å. In the fourth U4+ site, U4+ is bonded to six O2- atoms to form UO6 octahedra that share corners with six PO4 tetrahedra. There are a spread of U–O bond distances ranging from 2.23–2.26 Å. There are eight inequivalent P5+ sites. In the first P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with three UO6 octahedra and a cornercorner with one PO4 tetrahedra. The corner-sharing octahedra tilt angles range from 8–15°. There are a spread of P–O bond distances ranging from 1.52–1.59 Å. In the second P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with three UO6 octahedra and a cornercorner with one PO4 tetrahedra. The corner-sharing octahedra tilt angles range from 9–18°. There are a spread of P–O bond distances ranging from 1.52–1.59 Å. In the third P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with three UO6 octahedra and a cornercorner with one PO4 tetrahedra. The corner-sharing octahedra tilt angles range from 10–21°. There are a spread of P–O bond distances ranging from 1.52–1.59 Å. In the fourth P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with three UO6 octahedra and a cornercorner with one PO4 tetrahedra. The corner-sharing octahedra tilt angles range from 5–10°. There are a spread of P–O bond distances ranging from 1.53–1.60 Å. In the fifth P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with three UO6 octahedra and a cornercorner with one PO4 tetrahedra. The corner-sharing octahedra tilt angles range from 7–17°. There are a spread of P–O bond distances ranging from 1.52–1.60 Å. In the sixth P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with three UO6 octahedra and a cornercorner with one PO4 tetrahedra. The corner-sharing octahedra tilt angles range from 11–15°. There is three shorter (1.53 Å) and one longer (1.60 Å) P–O bond length. In the seventh P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with three UO6 octahedra and a cornercorner with one PO4 tetrahedra. The corner-sharing octahedra tilt angles range from 7–18°. There is three shorter (1.53 Å) and one longer (1.60 Å) P–O bond length. In the eighth P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with three UO6 octahedra and a cornercorner with one PO4 tetrahedra. The corner-sharing octahedra tilt angles range from 9–16°. There are a spread of P–O bond distances ranging from 1.52–1.60 Å. There are twenty-eight inequivalent O2- sites. In the first O2- site, O2- is bonded in a bent 150 degrees geometry to two P5+ atoms. In the second O2- site, O2- is bonded in a linear geometry to one U4+ and one P5+ atom. In the third O2- site, O2- is bonded in a distorted linear geometry to one U4+ and one P5+ atom. In the fourth O2- site, O2- is bonded in a linear geometry to one U4+ and one P5+ atom. In the fifth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one U4+ and one P5+ atom. In the sixth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one U4+ and one P5+ atom. In the seventh O2- site, O2- is bonded in a linear geometry to one U4+ and one P5+ atom. In the eighth O2- site, O2- is bonded in a bent 150 degrees geometry to two P5+ atoms. In the ninth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one U4+ and one P5+ atom. In the tenth O2- site, O2- is bonded in a distorted linear geometry to one U4+ and one P5+ atom. In the eleventh O2- site, O2- is bonded in a linear geometry to one U4+ and one P5+ atom. In the twelfth O2- site, O2- is bonded in a linear geometry to one U4+ and one P5+ atom. In the thirteenth O2- site, O2- is bonded in a linear geometry to one U4+ and one P5+ atom. In the fourteenth O2- site, O2- is bonded in a linear geometry to one U4+ and one P5+ atom. In the fifteenth O2- site, O2- is bonded in a bent 150 degrees geometry to two P5+ atoms. In the sixteenth O2- site, O2- is bonded in a distorted linear geometry to one U4+ and one P5+ atom. In the seventeenth O2- site, O2- is bonded in a linear geometry to one U4+ and one P5+ atom. In the eighteenth O2- site, O2- is bonded in a linear geometry to one U4+ and one P5+ atom. In the nineteenth O2- site, O2- is bonded in a distorted linear geometry to one U4+ and one P5+ atom. In the twentieth O2- site, O2- is bonded in a distorted linear geometry to one U4+ and one P5+ atom. In the twenty-first O2- site, O2- is bonded in a distorted linear geometry to one U4+ and one P5+ atom. In the twenty-second O2- site, O2- is bonded in a bent 150 degrees geometry to two P5+ atoms. In the twenty-third O2- site, O2- is bonded in a distorted linear geometry to one U4+ and one P5+ atom. In the twenty-fourth O2- site, O2- is bonded in a linear geometry to one U4+ and one P5+ atom. In the twenty-fifth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one U4+ and one P5+ atom. In the twenty-sixth O2- site, O2- is bonded in a distorted linear geometry to one U4+ and one P5+ atom. In the twenty-seventh O2- site, O2- is bonded in a linear geometry to one U4+ and one P5+ atom. In the twenty-eighth O2- site, O2- is bonded in a distorted linear geometry to one U4+ and one P5+ atom.