K2Ni(MoO4)2 crystallizes in the orthorhombic Cmce space group. There are two inequivalent K sites. In the first K site, K(1) is bonded in a 6-coordinate geometry to two equivalent O(4), two equivalent O(5), and two equivalent O(6) atoms. In the second K site, K(2) is bonded in a 7-coordinate geometry to one O(4), one O(5), one O(6), two equivalent O(1), and two equivalent O(2) atoms. There are two inequivalent Mo sites. In the first Mo site, Mo(1) is bonded to one O(3), one O(4), and two equivalent O(1) atoms to form MoO4 tetrahedra that share corners with four equivalent Ni(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 26-51°. In the second Mo site, Mo(2) is bonded to one O(5), one O(6), and two equivalent O(2) atoms to form MoO4 tetrahedra that share corners with two equivalent Ni(1)O6 octahedra. The corner-sharing octahedral tilt angles are 59°. Ni(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form NiO6 octahedra that share corners with two equivalent Mo(2)O4 tetrahedra, corners with four equivalent Mo(1)O4 tetrahedra, and  an edgeedge with one Ni(1)O6 octahedra. There are six inequivalent O sites. In the first O site, O(1) is bonded in a distorted bent 150 degrees geometry to one K(2), one Mo(1), and one Ni(1) atom. In the second O site, O(2) is bonded in a 3-coordinate geometry to one K(2), one Mo(2), and one Ni(1) atom. In the third O site, O(3) is bonded in a distorted trigonal planar geometry to one Mo(1) and two equivalent Ni(1) atoms. In the fourth O site, O(4) is bonded in a 4-coordinate geometry to one K(2), two equivalent K(1), and one Mo(1) atom. In the fifth O site, O(5) is bonded in a distorted rectangular see-saw-like geometry to one K(2), two equivalent K(1), and one Mo(2) atom. In the sixth O site, O(6) is bonded in a distorted rectangular see-saw-like geometry to one K(2), two equivalent K(1), and one Mo(2) atom.
K2Ni(MoO4)2 crystallizes in the orthorhombic Cmce space group. There are two inequivalent K sites. In the first K site, K(1) is bonded in a 6-coordinate geometry to two equivalent O(4), two equivalent O(5), and two equivalent O(6) atoms. Both K(1)-O(4) bond lengths are 2.82 Å. Both K(1)-O(5) bond lengths are 3.05 Å. Both K(1)-O(6) bond lengths are 2.99 Å. In the second K site, K(2) is bonded in a 7-coordinate geometry to one O(4), one O(5), one O(6), two equivalent O(1), and two equivalent O(2) atoms. The K(2)-O(4) bond length is 3.06 Å. The K(2)-O(5) bond length is 2.64 Å. The K(2)-O(6) bond length is 2.86 Å. Both K(2)-O(1) bond lengths are 2.97 Å. Both K(2)-O(2) bond lengths are 2.92 Å. There are two inequivalent Mo sites. In the first Mo site, Mo(1) is bonded to one O(3), one O(4), and two equivalent O(1) atoms to form MoO4 tetrahedra that share corners with four equivalent Ni(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 26-51°. The Mo(1)-O(3) bond length is 1.85 Å. The Mo(1)-O(4) bond length is 1.78 Å. Both Mo(1)-O(1) bond lengths are 1.78 Å. In the second Mo site, Mo(2) is bonded to one O(5), one O(6), and two equivalent O(2) atoms to form MoO4 tetrahedra that share corners with two equivalent Ni(1)O6 octahedra. The corner-sharing octahedral tilt angles are 59°. The Mo(2)-O(5) bond length is 1.79 Å. The Mo(2)-O(6) bond length is 1.79 Å. Both Mo(2)-O(2) bond lengths are 1.82 Å. Ni(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form NiO6 octahedra that share corners with two equivalent Mo(2)O4 tetrahedra, corners with four equivalent Mo(1)O4 tetrahedra, and  an edgeedge with one Ni(1)O6 octahedra. Both Ni(1)-O(1) bond lengths are 2.03 Å. Both Ni(1)-O(2) bond lengths are 2.11 Å. Both Ni(1)-O(3) bond lengths are 2.08 Å. There are six inequivalent O sites. In the first O site, O(1) is bonded in a distorted bent 150 degrees geometry to one K(2), one Mo(1), and one Ni(1) atom. In the second O site, O(2) is bonded in a 3-coordinate geometry to one K(2), one Mo(2), and one Ni(1) atom. In the third O site, O(3) is bonded in a distorted trigonal planar geometry to one Mo(1) and two equivalent Ni(1) atoms. In the fourth O site, O(4) is bonded in a 4-coordinate geometry to one K(2), two equivalent K(1), and one Mo(1) atom. In the fifth O site, O(5) is bonded in a distorted rectangular see-saw-like geometry to one K(2), two equivalent K(1), and one Mo(2) atom. In the sixth O site, O(6) is bonded in a distorted rectangular see-saw-like geometry to one K(2), two equivalent K(1), and one Mo(2) atom.