Rb3Dy(PO4)2 crystallizes in the trigonal P-3m1 space group. There are two inequivalent Rb sites. In the first Rb site, Rb(1) is bonded in a 7-coordinate geometry to one O(1) and six equivalent O(2) atoms. In the second Rb site, Rb(2) is bonded to six equivalent O(1) and six equivalent O(2) atoms to form RbO12 cuboctahedra that share edges with six equivalent Rb(2)O12 cuboctahedra, edges with six equivalent P(1)O4 tetrahedra, and faces with two equivalent Dy(1)O6 octahedra. Dy(1) is bonded to six equivalent O(2) atoms to form DyO6 octahedra that share corners with six equivalent P(1)O4 tetrahedra and faces with two equivalent Rb(2)O12 cuboctahedra. P(1) is bonded to one O(1) and three equivalent O(2) atoms to form PO4 tetrahedra that share corners with three equivalent Dy(1)O6 octahedra and edges with three equivalent Rb(2)O12 cuboctahedra. The corner-sharing octahedral tilt angles are 15°. There are two inequivalent O sites. In the first O site, O(1) is bonded in a distorted single-bond geometry to one Rb(1), three equivalent Rb(2), and one P(1) atom. In the second O site, O(2) is bonded in a 2-coordinate geometry to one Rb(2), two equivalent Rb(1), one Dy(1), and one P(1) atom.
Rb3Dy(PO4)2 crystallizes in the trigonal P-3m1 space group. There are two inequivalent Rb sites. In the first Rb site, Rb(1) is bonded in a 7-coordinate geometry to one O(1) and six equivalent O(2) atoms. The Rb(1)-O(1) bond length is 2.74 Å. All Rb(1)-O(2) bond lengths are 3.00 Å. In the second Rb site, Rb(2) is bonded to six equivalent O(1) and six equivalent O(2) atoms to form RbO12 cuboctahedra that share edges with six equivalent Rb(2)O12 cuboctahedra, edges with six equivalent P(1)O4 tetrahedra, and faces with two equivalent Dy(1)O6 octahedra. All Rb(2)-O(1) bond lengths are 3.40 Å. All Rb(2)-O(2) bond lengths are 3.37 Å. Dy(1) is bonded to six equivalent O(2) atoms to form DyO6 octahedra that share corners with six equivalent P(1)O4 tetrahedra and faces with two equivalent Rb(2)O12 cuboctahedra. All Dy(1)-O(2) bond lengths are 2.26 Å. P(1) is bonded to one O(1) and three equivalent O(2) atoms to form PO4 tetrahedra that share corners with three equivalent Dy(1)O6 octahedra and edges with three equivalent Rb(2)O12 cuboctahedra. The corner-sharing octahedral tilt angles are 15°. The P(1)-O(1) bond length is 1.53 Å. All P(1)-O(2) bond lengths are 1.57 Å. There are two inequivalent O sites. In the first O site, O(1) is bonded in a distorted single-bond geometry to one Rb(1), three equivalent Rb(2), and one P(1) atom. In the second O site, O(2) is bonded in a 2-coordinate geometry to one Rb(2), two equivalent Rb(1), one Dy(1), and one P(1) atom.