PrYSi2O7 crystallizes in the monoclinic P2_1/c space group. Pr(1) is bonded in a 6-coordinate geometry to one O(1), one O(2), one O(3), one O(4), one O(6), and one O(7) atom. Y(1) is bonded in a 7-coordinate geometry to one O(1), one O(2), one O(3), one O(4), one O(7), and two equivalent O(5) atoms. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(2), one O(3), one O(4), and one O(5) atom to form corner-sharing SiO4 tetrahedra. In the second Si site, Si(2) is bonded to one O(1), one O(2), one O(6), and one O(7) atom to form corner-sharing SiO4 tetrahedra. There are seven inequivalent O sites. In the first O site, O(5) is bonded in a 3-coordinate geometry to two equivalent Y(1) and one Si(1) atom. In the second O site, O(6) is bonded in a distorted linear geometry to one Pr(1) and one Si(2) atom. In the third O site, O(7) is bonded in a 3-coordinate geometry to one Pr(1), one Y(1), and one Si(2) atom. In the fourth O site, O(1) is bonded in a distorted trigonal planar geometry to one Pr(1), one Y(1), and one Si(2) atom. In the fifth O site, O(2) is bonded in a distorted bent 120 degrees geometry to one Pr(1), one Y(1), one Si(1), and one Si(2) atom. In the sixth O site, O(3) is bonded in a 3-coordinate geometry to one Pr(1), one Y(1), and one Si(1) atom. In the seventh O site, O(4) is bonded in a 3-coordinate geometry to one Pr(1), one Y(1), and one Si(1) atom.
PrYSi2O7 crystallizes in the monoclinic P2_1/c space group. Pr(1) is bonded in a 6-coordinate geometry to one O(1), one O(2), one O(3), one O(4), one O(6), and one O(7) atom. The Pr(1)-O(1) bond length is 2.43 Å. The Pr(1)-O(2) bond length is 2.83 Å. The Pr(1)-O(3) bond length is 2.33 Å. The Pr(1)-O(4) bond length is 2.53 Å. The Pr(1)-O(6) bond length is 2.26 Å. The Pr(1)-O(7) bond length is 2.40 Å. Y(1) is bonded in a 7-coordinate geometry to one O(1), one O(2), one O(3), one O(4), one O(7), and two equivalent O(5) atoms. The Y(1)-O(1) bond length is 2.29 Å. The Y(1)-O(2) bond length is 2.65 Å. The Y(1)-O(3) bond length is 2.32 Å. The Y(1)-O(4) bond length is 2.32 Å. The Y(1)-O(7) bond length is 2.41 Å. There is one shorter (2.28 Å) and one longer (2.58 Å) Y(1)-O(5) bond length. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(2), one O(3), one O(4), and one O(5) atom to form corner-sharing SiO4 tetrahedra. The Si(1)-O(2) bond length is 1.69 Å. The Si(1)-O(3) bond length is 1.63 Å. The Si(1)-O(4) bond length is 1.62 Å. The Si(1)-O(5) bond length is 1.62 Å. In the second Si site, Si(2) is bonded to one O(1), one O(2), one O(6), and one O(7) atom to form corner-sharing SiO4 tetrahedra. The Si(2)-O(1) bond length is 1.65 Å. The Si(2)-O(2) bond length is 1.73 Å. The Si(2)-O(6) bond length is 1.61 Å. The Si(2)-O(7) bond length is 1.65 Å. There are seven inequivalent O sites. In the first O site, O(5) is bonded in a 3-coordinate geometry to two equivalent Y(1) and one Si(1) atom. In the second O site, O(6) is bonded in a distorted linear geometry to one Pr(1) and one Si(2) atom. In the third O site, O(7) is bonded in a 3-coordinate geometry to one Pr(1), one Y(1), and one Si(2) atom. In the fourth O site, O(1) is bonded in a distorted trigonal planar geometry to one Pr(1), one Y(1), and one Si(2) atom. In the fifth O site, O(2) is bonded in a distorted bent 120 degrees geometry to one Pr(1), one Y(1), one Si(1), and one Si(2) atom. In the sixth O site, O(3) is bonded in a 3-coordinate geometry to one Pr(1), one Y(1), and one Si(1) atom. In the seventh O site, O(4) is bonded in a 3-coordinate geometry to one Pr(1), one Y(1), and one Si(1) atom.