K2LiNd4Nb2O12 crystallizes in the monoclinic C2 space group. K(1) is bonded in a 7-coordinate geometry to two equivalent O(2), two equivalent O(4), and three equivalent O(7) atoms. Li(1) is bonded in a 6-coordinate geometry to two equivalent O(2), two equivalent O(4), and two equivalent O(7) atoms. There are two inequivalent Nd sites. In the first Nd site, Nd(1) is bonded in a body-centered cubic geometry to one O(2), one O(3), one O(4), one O(5), two equivalent O(1), and two equivalent O(6) atoms. In the second Nd site, Nd(2) is bonded in a 7-coordinate geometry to one O(1), one O(2), one O(3), one O(4), one O(5), one O(6), and one O(7) atom. Nb(1) is bonded in a distorted trigonal bipyramidal geometry to one O(1), one O(2), one O(4), one O(6), and one O(7) atom. There are seven 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  a cornercorner with one O(3)Nd4 tetrahedra, corners with two equivalent O(1)Nd3Nb tetrahedra, corners with three equivalent O(5)Nd4 tetrahedra,  an edgeedge with one O(3)Nd4 tetrahedra, and edges with three equivalent O(6)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 two equivalent O(1)Nd3Nb tetrahedra, corners with six equivalent O(6)Nd3Nb tetrahedra, edges with two equivalent O(1)Nd3Nb tetrahedra, and edges with two equivalent O(5)Nd4 tetrahedra. In the fourth O site, O(4) 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 fifth O site, O(5) is bonded to two equivalent Nd(1) and two equivalent Nd(2) atoms to form ONd4 tetrahedra that share corners with two equivalent O(6)Nd3Nb tetrahedra, corners with six equivalent O(1)Nd3Nb tetrahedra, edges with two equivalent O(6)Nd3Nb tetrahedra, and edges with two equivalent O(3)Nd4 tetrahedra. In the sixth O site, O(6) is bonded to one Nd(2), two equivalent Nd(1), and one Nb(1) atom to form distorted ONd3Nb tetrahedra that share  a cornercorner with one O(5)Nd4 tetrahedra, corners with two equivalent O(6)Nd3Nb tetrahedra, corners with three equivalent O(3)Nd4 tetrahedra,  an edgeedge with one O(5)Nd4 tetrahedra, and edges with three equivalent O(1)Nd3Nb tetrahedra. In the seventh O site, O(7) 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 space group. K(1) is bonded in a 7-coordinate geometry to two equivalent O(2), two equivalent O(4), and three equivalent O(7) atoms. There is one shorter (2.83 Å) and one longer (2.87 Å) K(1)-O(2) bond length. There is one shorter (2.79 Å) and one longer (2.84 Å) K(1)-O(4) bond length. There are a spread of K(1)-O(7) bond distances ranging from 2.73-2.98 Å. Li(1) is bonded in a 6-coordinate geometry to two equivalent O(2), two equivalent O(4), and two equivalent O(7) atoms. Both Li(1)-O(2) bond lengths are 2.03 Å. Both Li(1)-O(4) bond lengths are 2.42 Å. Both Li(1)-O(7) bond lengths are 2.08 Å. There are two inequivalent Nd sites. In the first Nd site, Nd(1) is bonded in a body-centered cubic geometry to one O(2), one O(3), one O(4), one O(5), two equivalent O(1), and two equivalent O(6) atoms. The Nd(1)-O(2) bond length is 2.49 Å. The Nd(1)-O(3) bond length is 2.39 Å. The Nd(1)-O(4) bond length is 2.47 Å. The Nd(1)-O(5) bond length is 2.39 Å. There is one shorter (2.61 Å) and one longer (2.62 Å) Nd(1)-O(1) bond length. There is one shorter (2.61 Å) and one longer (2.64 Å) Nd(1)-O(6) bond length. In the second Nd site, Nd(2) is bonded in a 7-coordinate geometry to one O(1), one O(2), one O(3), one O(4), one O(5), one O(6), and one O(7) atom. The Nd(2)-O(1) bond length is 2.49 Å. The Nd(2)-O(2) bond length is 2.50 Å. The Nd(2)-O(3) bond length is 2.31 Å. The Nd(2)-O(4) bond length is 2.48 Å. The Nd(2)-O(5) bond length is 2.32 Å. The Nd(2)-O(6) bond length is 2.49 Å. The Nd(2)-O(7) bond length is 2.63 Å. Nb(1) is bonded in a distorted trigonal bipyramidal geometry to one O(1), one O(2), one O(4), one O(6), and one O(7) atom. The Nb(1)-O(1) bond length is 1.97 Å. The Nb(1)-O(2) bond length is 2.06 Å. The Nb(1)-O(4) bond length is 2.02 Å. The Nb(1)-O(6) bond length is 1.97 Å. The Nb(1)-O(7) bond length is 1.93 Å. There are seven 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  a cornercorner with one O(3)Nd4 tetrahedra, corners with two equivalent O(1)Nd3Nb tetrahedra, corners with three equivalent O(5)Nd4 tetrahedra,  an edgeedge with one O(3)Nd4 tetrahedra, and edges with three equivalent O(6)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 two equivalent O(1)Nd3Nb tetrahedra, corners with six equivalent O(6)Nd3Nb tetrahedra, edges with two equivalent O(1)Nd3Nb tetrahedra, and edges with two equivalent O(5)Nd4 tetrahedra. In the fourth O site, O(4) 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 fifth O site, O(5) is bonded to two equivalent Nd(1) and two equivalent Nd(2) atoms to form ONd4 tetrahedra that share corners with two equivalent O(6)Nd3Nb tetrahedra, corners with six equivalent O(1)Nd3Nb tetrahedra, edges with two equivalent O(6)Nd3Nb tetrahedra, and edges with two equivalent O(3)Nd4 tetrahedra. In the sixth O site, O(6) is bonded to one Nd(2), two equivalent Nd(1), and one Nb(1) atom to form distorted ONd3Nb tetrahedra that share  a cornercorner with one O(5)Nd4 tetrahedra, corners with two equivalent O(6)Nd3Nb tetrahedra, corners with three equivalent O(3)Nd4 tetrahedra,  an edgeedge with one O(5)Nd4 tetrahedra, and edges with three equivalent O(1)Nd3Nb tetrahedra. In the seventh O site, O(7) is bonded in a 6-coordinate geometry to three equivalent K(1), one Li(1), one Nd(2), and one Nb(1) atom.