K5Yb(MoO4)4 crystallizes in the monoclinic C2/c space group. There are three inequivalent K sites. In the first K site, K(1) is bonded in a 8-coordinate geometry to one O(1), one O(2), one O(4), one O(5), one O(7), one O(8), and two equivalent O(6) atoms. In the second K site, K(2) is bonded in a 8-coordinate geometry to one O(1), one O(3), one O(4), one O(5), one O(6), one O(7), and two equivalent O(8) atoms. In the third K site, K(3) is bonded in a distorted q6 geometry to two equivalent O(1), two equivalent O(2), two equivalent O(3), two equivalent O(6), and two equivalent O(8) atoms. Yb(1) is bonded to two equivalent O(4), two equivalent O(5), and two equivalent O(7) atoms to form YbO6 octahedra that share corners with two equivalent Mo(2)O4 tetrahedra and corners with four equivalent Mo(1)O4 tetrahedra. There are two inequivalent Mo sites. In the first Mo site, Mo(1) is bonded to one O(1), one O(2), one O(5), and one O(7) atom to form MoO4 tetrahedra that share corners with two equivalent Yb(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 47-49°. In the second Mo site, Mo(2) is bonded to one O(3), one O(4), one O(6), and one O(8) atom to form MoO4 tetrahedra that share  a cornercorner with one Yb(1)O6 octahedra. The corner-sharing octahedral tilt angles are 47°. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a 1-coordinate geometry to one K(1), one K(2), one K(3), and one Mo(1) atom. In the second O site, O(2) is bonded in a 3-coordinate geometry to one K(1), one K(3), and one Mo(1) atom. In the third O site, O(3) is bonded in a 3-coordinate geometry to one K(2), one K(3), and one Mo(2) atom. In the fourth O site, O(4) is bonded in a 4-coordinate geometry to one K(1), one K(2), one Yb(1), and one Mo(2) atom. In the fifth O site, O(5) is bonded in a 4-coordinate geometry to one K(1), one K(2), one Yb(1), and one Mo(1) atom. In the sixth O site, O(6) is bonded in a 5-coordinate geometry to one K(2), one K(3), two equivalent K(1), and one Mo(2) atom. In the seventh O site, O(7) is bonded in a 2-coordinate geometry to one K(1), one K(2), one Yb(1), and one Mo(1) atom. In the eighth O site, O(8) is bonded in a 1-coordinate geometry to one K(1), one K(3), two equivalent K(2), and one Mo(2) atom.
K5Yb(MoO4)4 crystallizes in the monoclinic C2/c space group. There are three inequivalent K sites. In the first K site, K(1) is bonded in a 8-coordinate geometry to one O(1), one O(2), one O(4), one O(5), one O(7), one O(8), and two equivalent O(6) atoms. The K(1)-O(1) bond length is 2.74 Å. The K(1)-O(2) bond length is 2.60 Å. The K(1)-O(4) bond length is 3.06 Å. The K(1)-O(5) bond length is 3.20 Å. The K(1)-O(7) bond length is 3.25 Å. The K(1)-O(8) bond length is 2.77 Å. There is one shorter (2.78 Å) and one longer (3.07 Å) K(1)-O(6) bond length. In the second K site, K(2) is bonded in a 8-coordinate geometry to one O(1), one O(3), one O(4), one O(5), one O(6), one O(7), and two equivalent O(8) atoms. The K(2)-O(1) bond length is 2.90 Å. The K(2)-O(3) bond length is 2.74 Å. The K(2)-O(4) bond length is 3.01 Å. The K(2)-O(5) bond length is 2.93 Å. The K(2)-O(6) bond length is 3.06 Å. The K(2)-O(7) bond length is 2.96 Å. There is one shorter (2.96 Å) and one longer (3.27 Å) K(2)-O(8) bond length. In the third K site, K(3) is bonded in a distorted q6 geometry to two equivalent O(1), two equivalent O(2), two equivalent O(3), two equivalent O(6), and two equivalent O(8) atoms. Both K(3)-O(1) bond lengths are 3.26 Å. Both K(3)-O(2) bond lengths are 2.96 Å. Both K(3)-O(3) bond lengths are 3.14 Å. Both K(3)-O(6) bond lengths are 2.96 Å. Both K(3)-O(8) bond lengths are 2.97 Å. Yb(1) is bonded to two equivalent O(4), two equivalent O(5), and two equivalent O(7) atoms to form YbO6 octahedra that share corners with two equivalent Mo(2)O4 tetrahedra and corners with four equivalent Mo(1)O4 tetrahedra. Both Yb(1)-O(4) bond lengths are 2.35 Å. Both Yb(1)-O(5) bond lengths are 2.34 Å. Both Yb(1)-O(7) bond lengths are 2.35 Å. There are two inequivalent Mo sites. In the first Mo site, Mo(1) is bonded to one O(1), one O(2), one O(5), and one O(7) atom to form MoO4 tetrahedra that share corners with two equivalent Yb(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 47-49°. The Mo(1)-O(1) bond length is 1.80 Å. The Mo(1)-O(2) bond length is 1.78 Å. The Mo(1)-O(5) bond length is 1.81 Å. The Mo(1)-O(7) bond length is 1.81 Å. In the second Mo site, Mo(2) is bonded to one O(3), one O(4), one O(6), and one O(8) atom to form MoO4 tetrahedra that share  a cornercorner with one Yb(1)O6 octahedra. The corner-sharing octahedral tilt angles are 47°. The Mo(2)-O(3) bond length is 1.79 Å. The Mo(2)-O(4) bond length is 1.81 Å. The Mo(2)-O(6) bond length is 1.81 Å. The Mo(2)-O(8) bond length is 1.80 Å. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a 1-coordinate geometry to one K(1), one K(2), one K(3), and one Mo(1) atom. In the second O site, O(2) is bonded in a 3-coordinate geometry to one K(1), one K(3), and one Mo(1) atom. In the third O site, O(3) is bonded in a 3-coordinate geometry to one K(2), one K(3), and one Mo(2) atom. In the fourth O site, O(4) is bonded in a 4-coordinate geometry to one K(1), one K(2), one Yb(1), and one Mo(2) atom. In the fifth O site, O(5) is bonded in a 4-coordinate geometry to one K(1), one K(2), one Yb(1), and one Mo(1) atom. In the sixth O site, O(6) is bonded in a 5-coordinate geometry to one K(2), one K(3), two equivalent K(1), and one Mo(2) atom. In the seventh O site, O(7) is bonded in a 2-coordinate geometry to one K(1), one K(2), one Yb(1), and one Mo(1) atom. In the eighth O site, O(8) is bonded in a 1-coordinate geometry to one K(1), one K(3), two equivalent K(2), and one Mo(2) atom.