Materials Data on Pr2Ta2O9 by Materials Project
Pr2Ta2O9 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. Pr4+ is bonded in a 9-coordinate geometry to nine O2- atoms. There are a spread of Pr–O bond distances ranging from 2.40–2.62 Å. Ta5+ is bonded to six O2- atoms to form a mixture of distorted corner and edge-sharing TaO6 octahedra. The corner-sharing octahedra tilt angles range from 0–13°. There are a spread of Ta–O bond distances ranging from 1.91–2.22 Å. There are five inequivalent O2- sites. In the first O2- site, O2- is bonded in a 4-coordinate geometry to two equivalent Pr4+ and two equivalent Ta5+ atoms. In the second O2- site, O2- is bonded in a 3-coordinate geometry to three equivalent Pr4+ atoms. In the third O2- site, O2- is bonded in a linear geometry to two equivalent Ta5+ atoms. In the fourth O2- site, O2- is bonded in a distorted T-shaped geometry to one Pr4+ and two equivalent Ta5+ atoms. In the fifth O2- site, O2- is bonded in a 4-coordinate geometry to three equivalent Pr4+ and one Ta5+ atom.