Materials Data on PrYSi2O7 by Materials Project
PrYSi2O7 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. Pr3+ is bonded to six O2- atoms to form distorted PrO6 octahedra that share corners with three equivalent SiO4 tetrahedra. There are a spread of Pr–O bond distances ranging from 2.32–2.67 Å. Y3+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Y–O bond distances ranging from 2.19–2.52 Å. There are two inequivalent Si4+ sites. In the first Si4+ site, Si4+ is bonded in a trigonal non-coplanar geometry to three O2- atoms. There is two shorter (1.64 Å) and one longer (1.66 Å) Si–O bond length. In the second Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with three equivalent PrO6 octahedra. The corner-sharing octahedra tilt angles range from 51–69°. There are a spread of Si–O bond distances ranging from 1.63–1.67 Å. There are seven inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted trigonal non-coplanar geometry to one Pr3+, one Y3+, and one Si4+ atom. In the second O2- site, O2- is bonded in a distorted trigonal planar geometry to one Pr3+, one Y3+, and one Si4+ atom. In the third O2- site, O2- is bonded in a distorted trigonal planar geometry to one Pr3+, one Y3+, and one Si4+ atom. In the fourth O2- site, O2- is bonded in a 1-coordinate geometry to one Pr3+, one Y3+, and one Si4+ atom. In the fifth O2- site, O2- is bonded in a bent 150 degrees geometry to two Si4+ atoms. In the sixth O2- site, O2- is bonded in a distorted single-bond geometry to one Pr3+, one Y3+, and one Si4+ atom. In the seventh O2- site, O2- is bonded in a bent 150 degrees geometry to one Pr3+ and one Y3+ atom.