K2LiNd4Nb2O12 crystallizes in the monoclinic C2/m space group. K(1) is bonded in a 7-coordinate geometry to three equivalent O(4) and four equivalent O(2) atoms. Li(1) is bonded to two equivalent O(4) and four equivalent O(2) atoms to form LiO6 octahedra that share faces with two equivalent Nb(1)O5 trigonal bipyramids. There are two inequivalent Nd sites. In the first Nd site, Nd(1) is bonded in a body-centered cubic geometry to two equivalent O(2), two equivalent O(3), and four equivalent O(1) atoms. In the second Nd site, Nd(2) is bonded in a 7-coordinate geometry to one O(4), two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms. Nb(1) is bonded to one O(4), two equivalent O(1), and two equivalent O(2) atoms to form distorted NbO5 trigonal bipyramids that share  a faceface with one Li(1)O6 octahedra. There are four inequivalent O sites. In the first O site, O(1) is bonded to one Nd(2), two equivalent Nd(1), and one Nb(1) atom to form distorted ONd3Nb tetrahedra that share corners with two equivalent O(1)Nd3Nb tetrahedra, corners with four equivalent O(3)Nd4 tetrahedra,  an edgeedge with one O(3)Nd4 tetrahedra, and edges with three equivalent O(1)Nd3Nb tetrahedra. In the second O site, O(2) is bonded in a 6-coordinate geometry to two equivalent K(1), one Li(1), one Nd(1), one Nd(2), and one Nb(1) atom. In the third O site, O(3) is bonded to two equivalent Nd(1) and two equivalent Nd(2) atoms to form ONd4 tetrahedra that share corners with eight equivalent O(1)Nd3Nb tetrahedra, edges with two equivalent O(1)Nd3Nb tetrahedra, and edges with two equivalent O(3)Nd4 tetrahedra. In the fourth O site, O(4) is bonded in a 6-coordinate geometry to three equivalent K(1), one Li(1), one Nd(2), and one Nb(1) atom.
K2LiNd4Nb2O12 crystallizes in the monoclinic C2/m space group. K(1) is bonded in a 7-coordinate geometry to three equivalent O(4) and four equivalent O(2) atoms. There is one shorter (2.72 Å) and two longer (2.94 Å) K(1)-O(4) bond lengths. There are two shorter (2.81 Å) and two longer (2.83 Å) K(1)-O(2) bond lengths. Li(1) is bonded to two equivalent O(4) and four equivalent O(2) atoms to form LiO6 octahedra that share faces with two equivalent Nb(1)O5 trigonal bipyramids. Both Li(1)-O(4) bond lengths are 2.08 Å. All Li(1)-O(2) bond lengths are 2.20 Å. There are two inequivalent Nd sites. In the first Nd site, Nd(1) is bonded in a body-centered cubic geometry to two equivalent O(2), two equivalent O(3), and four equivalent O(1) atoms. Both Nd(1)-O(2) bond lengths are 2.49 Å. Both Nd(1)-O(3) bond lengths are 2.39 Å. There are two shorter (2.60 Å) and two longer (2.63 Å) Nd(1)-O(1) bond lengths. In the second Nd site, Nd(2) is bonded in a 7-coordinate geometry to one O(4), two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms. The Nd(2)-O(4) bond length is 2.64 Å. Both Nd(2)-O(1) bond lengths are 2.49 Å. Both Nd(2)-O(2) bond lengths are 2.49 Å. Both Nd(2)-O(3) bond lengths are 2.32 Å. Nb(1) is bonded to one O(4), two equivalent O(1), and two equivalent O(2) atoms to form distorted NbO5 trigonal bipyramids that share  a faceface with one Li(1)O6 octahedra. The Nb(1)-O(4) bond length is 1.92 Å. Both Nb(1)-O(1) bond lengths are 1.97 Å. Both Nb(1)-O(2) bond lengths are 2.04 Å. There are four inequivalent O sites. In the first O site, O(1) is bonded to one Nd(2), two equivalent Nd(1), and one Nb(1) atom to form distorted ONd3Nb tetrahedra that share corners with two equivalent O(1)Nd3Nb tetrahedra, corners with four equivalent O(3)Nd4 tetrahedra,  an edgeedge with one O(3)Nd4 tetrahedra, and edges with three equivalent O(1)Nd3Nb tetrahedra. In the second O site, O(2) is bonded in a 6-coordinate geometry to two equivalent K(1), one Li(1), one Nd(1), one Nd(2), and one Nb(1) atom. In the third O site, O(3) is bonded to two equivalent Nd(1) and two equivalent Nd(2) atoms to form ONd4 tetrahedra that share corners with eight equivalent O(1)Nd3Nb tetrahedra, edges with two equivalent O(1)Nd3Nb tetrahedra, and edges with two equivalent O(3)Nd4 tetrahedra. In the fourth O site, O(4) is bonded in a 6-coordinate geometry to three equivalent K(1), one Li(1), one Nd(2), and one Nb(1) atom.