Rb3HoO3 crystallizes in the monoclinic P2_1/c space group. There are three inequivalent Rb sites. In the first Rb site, Rb(1) is bonded in a 3-coordinate geometry to one O(1), one O(2), and one O(3) atom. In the second Rb site, Rb(2) is bonded in a 4-coordinate geometry to one O(1), one O(3), and two equivalent O(2) atoms. In the third Rb site, Rb(3) is bonded to two equivalent O(1) and two equivalent O(3) atoms to form distorted RbO4 trigonal pyramids that share corners with two equivalent Ho(1)O4 tetrahedra, corners with two equivalent Rb(3)O4 trigonal pyramids,  an edgeedge with one Ho(1)O4 tetrahedra, and  an edgeedge with one Rb(3)O4 trigonal pyramid. Ho(1) is bonded to one O(1), one O(3), and two equivalent O(2) atoms to form HoO4 tetrahedra that share corners with two equivalent Rb(3)O4 trigonal pyramids,  an edgeedge with one Ho(1)O4 tetrahedra, and  an edgeedge with one Rb(3)O4 trigonal pyramid. There are three inequivalent O sites. In the first O site, O(1) is bonded in a 5-coordinate geometry to one Rb(1), one Rb(2), two equivalent Rb(3), and one Ho(1) atom. In the second O site, O(2) is bonded in a 5-coordinate geometry to one Rb(1), two equivalent Rb(2), and two equivalent Ho(1) atoms. In the third O site, O(3) is bonded in a 5-coordinate geometry to one Rb(1), one Rb(2), two equivalent Rb(3), and one Ho(1) atom.
Rb3HoO3 crystallizes in the monoclinic P2_1/c space group. There are three inequivalent Rb sites. In the first Rb site, Rb(1) is bonded in a 3-coordinate geometry to one O(1), one O(2), and one O(3) atom. The Rb(1)-O(1) bond length is 2.71 Å. The Rb(1)-O(2) bond length is 3.22 Å. The Rb(1)-O(3) bond length is 2.77 Å. In the second Rb site, Rb(2) is bonded in a 4-coordinate geometry to one O(1), one O(3), and two equivalent O(2) atoms. The Rb(2)-O(1) bond length is 2.95 Å. The Rb(2)-O(3) bond length is 2.84 Å. There is one shorter (2.86 Å) and one longer (2.98 Å) Rb(2)-O(2) bond length. In the third Rb site, Rb(3) is bonded to two equivalent O(1) and two equivalent O(3) atoms to form distorted RbO4 trigonal pyramids that share corners with two equivalent Ho(1)O4 tetrahedra, corners with two equivalent Rb(3)O4 trigonal pyramids,  an edgeedge with one Ho(1)O4 tetrahedra, and  an edgeedge with one Rb(3)O4 trigonal pyramid. There is one shorter (2.84 Å) and one longer (2.91 Å) Rb(3)-O(1) bond length. There is one shorter (2.88 Å) and one longer (2.97 Å) Rb(3)-O(3) bond length. Ho(1) is bonded to one O(1), one O(3), and two equivalent O(2) atoms to form HoO4 tetrahedra that share corners with two equivalent Rb(3)O4 trigonal pyramids,  an edgeedge with one Ho(1)O4 tetrahedra, and  an edgeedge with one Rb(3)O4 trigonal pyramid. The Ho(1)-O(1) bond length is 2.11 Å. The Ho(1)-O(3) bond length is 2.11 Å. There is one shorter (2.18 Å) and one longer (2.21 Å) Ho(1)-O(2) bond length. There are three inequivalent O sites. In the first O site, O(1) is bonded in a 5-coordinate geometry to one Rb(1), one Rb(2), two equivalent Rb(3), and one Ho(1) atom. In the second O site, O(2) is bonded in a 5-coordinate geometry to one Rb(1), two equivalent Rb(2), and two equivalent Ho(1) atoms. In the third O site, O(3) is bonded in a 5-coordinate geometry to one Rb(1), one Rb(2), two equivalent Rb(3), and one Ho(1) atom.