Materials Data on Pr9O16 by Materials Project
Pr9O16 crystallizes in the triclinic P-1 space group. The structure is three-dimensional. there are five inequivalent Pr+3.56+ sites. In the first Pr+3.56+ site, Pr+3.56+ is bonded in a body-centered cubic geometry to eight O2- atoms. There are a spread of Pr–O bond distances ranging from 2.45–2.68 Å. In the second Pr+3.56+ site, Pr+3.56+ is bonded to seven O2- atoms to form distorted PrO7 hexagonal pyramids that share a cornercorner with one PrO6 octahedra, a cornercorner with one PrO7 pentagonal bipyramid, edges with two equivalent PrO7 hexagonal pyramids, an edgeedge with one PrO6 octahedra, and edges with two equivalent PrO7 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 58°. There are a spread of Pr–O bond distances ranging from 2.41–2.56 Å. In the third Pr+3.56+ site, Pr+3.56+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of Pr–O bond distances ranging from 2.39–2.57 Å. In the fourth Pr+3.56+ site, Pr+3.56+ is bonded to six O2- atoms to form a mixture of distorted edge and corner-sharing PrO6 octahedra. There are a spread of Pr–O bond distances ranging from 2.35–2.41 Å. In the fifth Pr+3.56+ site, Pr+3.56+ is bonded to seven O2- atoms to form distorted PrO7 pentagonal bipyramids that share a cornercorner with one PrO7 hexagonal pyramid, a cornercorner with one PrO6 octahedra, edges with two equivalent PrO7 hexagonal pyramids, an edgeedge with one PrO6 octahedra, and an edgeedge with one PrO7 pentagonal bipyramid. The corner-sharing octahedral tilt angles are 51°. There are a spread of Pr–O bond distances ranging from 2.39–2.55 Å. There are eight inequivalent O2- sites. In the first O2- site, O2- is bonded to four Pr+3.56+ atoms to form a mixture of distorted edge and corner-sharing OPr4 tetrahedra. In the second O2- site, O2- is bonded to four Pr+3.56+ atoms to form a mixture of edge and corner-sharing OPr4 tetrahedra. In the third O2- site, O2- is bonded to four Pr+3.56+ atoms to form a mixture of edge and corner-sharing OPr4 tetrahedra. In the fourth O2- site, O2- is bonded to four Pr+3.56+ atoms to form a mixture of distorted edge and corner-sharing OPr4 tetrahedra. In the fifth O2- site, O2- is bonded to four Pr+3.56+ atoms to form a mixture of edge and corner-sharing OPr4 tetrahedra. In the sixth O2- site, O2- is bonded to four Pr+3.56+ atoms to form a mixture of edge and corner-sharing OPr4 tetrahedra. In the seventh O2- site, O2- is bonded to four Pr+3.56+ atoms to form a mixture of distorted edge and corner-sharing OPr4 tetrahedra. In the eighth O2- site, O2- is bonded to four Pr+3.56+ atoms to form a mixture of distorted edge and corner-sharing OPr4 tetrahedra.