K2LiNd4Nb2O12 crystallizes in the triclinic P1 space group. There are two inequivalent K sites. In the first K site, K(1) is bonded in a 8-coordinate geometry to one Li(1), one O(10), one O(11), one O(2), one O(5), one O(8), and two equivalent O(9) atoms. In the second K site, K(2) is bonded in a 8-coordinate geometry to one Li(1), one O(11), one O(2), one O(5), one O(8), one O(9), and two equivalent O(10) atoms. Li(1) is bonded in a bent 120 degrees geometry to one K(1), one K(2), one O(4), and one O(7) atom. There are four inequivalent Nd sites. In the first Nd site, Nd(1) is bonded in a distorted body-centered cubic geometry to one O(1), one O(11), one O(12), one O(3), one O(4), one O(6), one O(7), and one O(8) atom. In the second Nd site, Nd(2) is bonded in a 7-coordinate geometry to one O(11), one O(2), one O(3), one O(5), one O(6), one O(8), and one O(9) atom. In the third Nd site, Nd(3) is bonded to one O(1), one O(10), one O(12), one O(3), one O(4), one O(6), and one O(7) atom to form distorted NdO7 hexagonal pyramids that share  a cornercorner with one Nb(2)O5 trigonal bipyramid, corners with two equivalent Nb(1)O5 trigonal bipyramids, and  an edgeedge with one Nb(1)O5 trigonal bipyramid. In the fourth Nd site, Nd(4) is bonded in a distorted body-centered cubic geometry to one O(1), one O(11), one O(12), one O(2), one O(3), one O(5), one O(6), and one O(8) atom. There are two inequivalent Nb sites. In the first Nb site, Nb(1) is bonded to one O(1), one O(12), one O(4), one O(7), and one O(9) atom to form distorted NbO5 trigonal bipyramids that share corners with two equivalent Nd(3)O7 hexagonal pyramids and  an edgeedge with one Nd(3)O7 hexagonal pyramid. In the second Nb site, Nb(2) is bonded to one O(10), one O(11), one O(2), one O(5), and one O(8) atom to form distorted NbO5 trigonal bipyramids that share  a cornercorner with one Nd(3)O7 hexagonal pyramid. There are twelve inequivalent O sites. In the first O site, O(1) is bonded to one Nd(1), one Nd(3), one Nd(4), and one Nb(1) atom to form distorted ONd3Nb tetrahedra that share  a cornercorner with one O(3)Nd4 tetrahedra, corners with three equivalent O(6)Nd4 tetrahedra,  a cornercorner with one O(2)K2Nd2Nb trigonal bipyramid,  a cornercorner with one O(5)K2Nd2Nb trigonal bipyramid,  an edgeedge with one O(3)Nd4 tetrahedra, and edges with two equivalent O(12)Nd3Nb tetrahedra. In the second O site, O(2) is bonded to one K(1), one K(2), one Nd(2), one Nd(4), and one Nb(2) atom to form distorted OK2Nd2Nb trigonal bipyramids that share  a cornercorner with one O(1)Nd3Nb tetrahedra,  a cornercorner with one O(12)Nd3Nb tetrahedra, corners with two equivalent O(6)Nd4 tetrahedra,  an edgeedge with one O(3)Nd4 tetrahedra,  an edgeedge with one O(5)K2Nd2Nb trigonal bipyramid, and  a faceface with one O(5)K2Nd2Nb trigonal bipyramid. In the third O site, O(3) is bonded to one Nd(1), one Nd(2), one Nd(3), and one Nd(4) atom to form ONd4 tetrahedra that share  a cornercorner with one O(1)Nd3Nb tetrahedra, corners with three equivalent O(12)Nd3Nb tetrahedra, corners with two equivalent O(5)K2Nd2Nb trigonal bipyramids,  an edgeedge with one O(1)Nd3Nb tetrahedra, edges with two equivalent O(6)Nd4 tetrahedra, and  an edgeedge with one O(2)K2Nd2Nb trigonal bipyramid. In the fourth O site, O(4) is bonded in a 4-coordinate geometry to one Li(1), one Nd(1), one Nd(3), and one Nb(1) atom. In the fifth O site, O(5) is bonded to one K(1), one K(2), one Nd(2), one Nd(4), and one Nb(2) atom to form distorted OK2Nd2Nb trigonal bipyramids that share  a cornercorner with one O(1)Nd3Nb tetrahedra,  a cornercorner with one O(12)Nd3Nb tetrahedra, corners with two equivalent O(3)Nd4 tetrahedra,  an edgeedge with one O(6)Nd4 tetrahedra,  an edgeedge with one O(2)K2Nd2Nb trigonal bipyramid, and  a faceface with one O(2)K2Nd2Nb trigonal bipyramid. In the sixth O site, O(6) is bonded to one Nd(1), one Nd(2), one Nd(3), and one Nd(4) atom to form ONd4 tetrahedra that share  a cornercorner with one O(12)Nd3Nb tetrahedra, corners with three equivalent O(1)Nd3Nb tetrahedra, corners with two equivalent O(2)K2Nd2Nb trigonal bipyramids,  an edgeedge with one O(12)Nd3Nb tetrahedra, edges with two equivalent O(3)Nd4 tetrahedra, and  an edgeedge with one O(5)K2Nd2Nb trigonal bipyramid. In the seventh O site, O(7) is bonded in a 4-coordinate geometry to one Li(1), one Nd(1), one Nd(3), and one Nb(1) atom. In the eighth O site, O(8) is bonded in a 6-coordinate geometry to one K(1), one K(2), one Nd(1), one Nd(2), one Nd(4), and one Nb(2) atom. In the ninth O site, O(9) is bonded in a 5-coordinate geometry to one K(2), two equivalent K(1), one Nd(2), and one Nb(1) atom. In the tenth O site, O(10) is bonded in a 5-coordinate geometry to one K(1), two equivalent K(2), one Nd(3), and one Nb(2) atom. In the eleventh O site, O(11) is bonded in a 6-coordinate geometry to one K(1), one K(2), one Nd(1), one Nd(2), one Nd(4), and one Nb(2) atom. In the twelfth O site, O(12) is bonded to one Nd(1), one Nd(3), one Nd(4), and one Nb(1) atom to form distorted ONd3Nb tetrahedra that share  a cornercorner with one O(6)Nd4 tetrahedra, corners with three equivalent O(3)Nd4 tetrahedra,  a cornercorner with one O(2)K2Nd2Nb trigonal bipyramid,  a cornercorner with one O(5)K2Nd2Nb trigonal bipyramid,  an edgeedge with one O(6)Nd4 tetrahedra, and edges with two equivalent O(1)Nd3Nb tetrahedra.
K2LiNd4Nb2O12 crystallizes in the triclinic P1 space group. There are two inequivalent K sites. In the first K site, K(1) is bonded in a 8-coordinate geometry to one Li(1), one O(10), one O(11), one O(2), one O(5), one O(8), and two equivalent O(9) atoms. The K(1)-Li(1) bond length is 2.55 Å. The K(1)-O(10) bond length is 2.52 Å. The K(1)-O(11) bond length is 2.96 Å. The K(1)-O(2) bond length is 2.69 Å. The K(1)-O(5) bond length is 2.69 Å. The K(1)-O(8) bond length is 2.96 Å. There is one shorter (2.99 Å) and one longer (3.02 Å) K(1)-O(9) bond length. In the second K site, K(2) is bonded in a 8-coordinate geometry to one Li(1), one O(11), one O(2), one O(5), one O(8), one O(9), and two equivalent O(10) atoms. The K(2)-Li(1) bond length is 2.48 Å. The K(2)-O(11) bond length is 2.90 Å. The K(2)-O(2) bond length is 2.83 Å. The K(2)-O(5) bond length is 2.84 Å. The K(2)-O(8) bond length is 2.90 Å. The K(2)-O(9) bond length is 2.47 Å. There is one shorter (2.90 Å) and one longer (2.92 Å) K(2)-O(10) bond length. Li(1) is bonded in a bent 120 degrees geometry to one K(1), one K(2), one O(4), and one O(7) atom. The Li(1)-O(4) bond length is 1.75 Å. The Li(1)-O(7) bond length is 1.75 Å. There are four inequivalent Nd sites. In the first Nd site, Nd(1) is bonded in a distorted body-centered cubic geometry to one O(1), one O(11), one O(12), one O(3), one O(4), one O(6), one O(7), and one O(8) atom. The Nd(1)-O(1) bond length is 2.67 Å. The Nd(1)-O(11) bond length is 2.47 Å. The Nd(1)-O(12) bond length is 2.67 Å. The Nd(1)-O(3) bond length is 2.42 Å. The Nd(1)-O(4) bond length is 2.66 Å. The Nd(1)-O(6) bond length is 2.42 Å. The Nd(1)-O(7) bond length is 2.65 Å. The Nd(1)-O(8) bond length is 2.47 Å. In the second Nd site, Nd(2) is bonded in a 7-coordinate geometry to one O(11), one O(2), one O(3), one O(5), one O(6), one O(8), and one O(9) atom. The Nd(2)-O(11) bond length is 2.46 Å. The Nd(2)-O(2) bond length is 2.50 Å. The Nd(2)-O(3) bond length is 2.30 Å. The Nd(2)-O(5) bond length is 2.50 Å. The Nd(2)-O(6) bond length is 2.30 Å. The Nd(2)-O(8) bond length is 2.46 Å. The Nd(2)-O(9) bond length is 2.64 Å. In the third Nd site, Nd(3) is bonded to one O(1), one O(10), one O(12), one O(3), one O(4), one O(6), and one O(7) atom to form distorted NdO7 hexagonal pyramids that share  a cornercorner with one Nb(2)O5 trigonal bipyramid, corners with two equivalent Nb(1)O5 trigonal bipyramids, and  an edgeedge with one Nb(1)O5 trigonal bipyramid. The Nd(3)-O(1) bond length is 2.53 Å. The Nd(3)-O(10) bond length is 2.56 Å. The Nd(3)-O(12) bond length is 2.53 Å. The Nd(3)-O(3) bond length is 2.35 Å. The Nd(3)-O(4) bond length is 2.53 Å. The Nd(3)-O(6) bond length is 2.34 Å. The Nd(3)-O(7) bond length is 2.52 Å. In the fourth Nd site, Nd(4) is bonded in a distorted body-centered cubic geometry to one O(1), one O(11), one O(12), one O(2), one O(3), one O(5), one O(6), and one O(8) atom. The Nd(4)-O(1) bond length is 2.52 Å. The Nd(4)-O(11) bond length is 2.86 Å. The Nd(4)-O(12) bond length is 2.52 Å. The Nd(4)-O(2) bond length is 2.51 Å. The Nd(4)-O(3) bond length is 2.38 Å. The Nd(4)-O(5) bond length is 2.50 Å. The Nd(4)-O(6) bond length is 2.39 Å. The Nd(4)-O(8) bond length is 2.86 Å. There are two inequivalent Nb sites. In the first Nb site, Nb(1) is bonded to one O(1), one O(12), one O(4), one O(7), and one O(9) atom to form distorted NbO5 trigonal bipyramids that share corners with two equivalent Nd(3)O7 hexagonal pyramids and  an edgeedge with one Nd(3)O7 hexagonal pyramid. The Nb(1)-O(1) bond length is 2.02 Å. The Nb(1)-O(12) bond length is 2.02 Å. The Nb(1)-O(4) bond length is 1.98 Å. The Nb(1)-O(7) bond length is 1.98 Å. The Nb(1)-O(9) bond length is 1.86 Å. In the second Nb site, Nb(2) is bonded to one O(10), one O(11), one O(2), one O(5), and one O(8) atom to form distorted NbO5 trigonal bipyramids that share  a cornercorner with one Nd(3)O7 hexagonal pyramid. The Nb(2)-O(10) bond length is 1.92 Å. The Nb(2)-O(11) bond length is 2.09 Å. The Nb(2)-O(2) bond length is 1.95 Å. The Nb(2)-O(5) bond length is 1.95 Å. The Nb(2)-O(8) bond length is 2.09 Å. There are twelve inequivalent O sites. In the first O site, O(1) is bonded to one Nd(1), one Nd(3), one Nd(4), and one Nb(1) atom to form distorted ONd3Nb tetrahedra that share  a cornercorner with one O(3)Nd4 tetrahedra, corners with three equivalent O(6)Nd4 tetrahedra,  a cornercorner with one O(2)K2Nd2Nb trigonal bipyramid,  a cornercorner with one O(5)K2Nd2Nb trigonal bipyramid,  an edgeedge with one O(3)Nd4 tetrahedra, and edges with two equivalent O(12)Nd3Nb tetrahedra. In the second O site, O(2) is bonded to one K(1), one K(2), one Nd(2), one Nd(4), and one Nb(2) atom to form distorted OK2Nd2Nb trigonal bipyramids that share  a cornercorner with one O(1)Nd3Nb tetrahedra,  a cornercorner with one O(12)Nd3Nb tetrahedra, corners with two equivalent O(6)Nd4 tetrahedra,  an edgeedge with one O(3)Nd4 tetrahedra,  an edgeedge with one O(5)K2Nd2Nb trigonal bipyramid, and  a faceface with one O(5)K2Nd2Nb trigonal bipyramid. In the third O site, O(3) is bonded to one Nd(1), one Nd(2), one Nd(3), and one Nd(4) atom to form ONd4 tetrahedra that share  a cornercorner with one O(1)Nd3Nb tetrahedra, corners with three equivalent O(12)Nd3Nb tetrahedra, corners with two equivalent O(5)K2Nd2Nb trigonal bipyramids,  an edgeedge with one O(1)Nd3Nb tetrahedra, edges with two equivalent O(6)Nd4 tetrahedra, and  an edgeedge with one O(2)K2Nd2Nb trigonal bipyramid. In the fourth O site, O(4) is bonded in a 4-coordinate geometry to one Li(1), one Nd(1), one Nd(3), and one Nb(1) atom. In the fifth O site, O(5) is bonded to one K(1), one K(2), one Nd(2), one Nd(4), and one Nb(2) atom to form distorted OK2Nd2Nb trigonal bipyramids that share  a cornercorner with one O(1)Nd3Nb tetrahedra,  a cornercorner with one O(12)Nd3Nb tetrahedra, corners with two equivalent O(3)Nd4 tetrahedra,  an edgeedge with one O(6)Nd4 tetrahedra,  an edgeedge with one O(2)K2Nd2Nb trigonal bipyramid, and  a faceface with one O(2)K2Nd2Nb trigonal bipyramid. In the sixth O site, O(6) is bonded to one Nd(1), one Nd(2), one Nd(3), and one Nd(4) atom to form ONd4 tetrahedra that share  a cornercorner with one O(12)Nd3Nb tetrahedra, corners with three equivalent O(1)Nd3Nb tetrahedra, corners with two equivalent O(2)K2Nd2Nb trigonal bipyramids,  an edgeedge with one O(12)Nd3Nb tetrahedra, edges with two equivalent O(3)Nd4 tetrahedra, and  an edgeedge with one O(5)K2Nd2Nb trigonal bipyramid. In the seventh O site, O(7) is bonded in a 4-coordinate geometry to one Li(1), one Nd(1), one Nd(3), and one Nb(1) atom. In the eighth O site, O(8) is bonded in a 6-coordinate geometry to one K(1), one K(2), one Nd(1), one Nd(2), one Nd(4), and one Nb(2) atom. In the ninth O site, O(9) is bonded in a 5-coordinate geometry to one K(2), two equivalent K(1), one Nd(2), and one Nb(1) atom. In the tenth O site, O(10) is bonded in a 5-coordinate geometry to one K(1), two equivalent K(2), one Nd(3), and one Nb(2) atom. In the eleventh O site, O(11) is bonded in a 6-coordinate geometry to one K(1), one K(2), one Nd(1), one Nd(2), one Nd(4), and one Nb(2) atom. In the twelfth O site, O(12) is bonded to one Nd(1), one Nd(3), one Nd(4), and one Nb(1) atom to form distorted ONd3Nb tetrahedra that share  a cornercorner with one O(6)Nd4 tetrahedra, corners with three equivalent O(3)Nd4 tetrahedra,  a cornercorner with one O(2)K2Nd2Nb trigonal bipyramid,  a cornercorner with one O(5)K2Nd2Nb trigonal bipyramid,  an edgeedge with one O(6)Nd4 tetrahedra, and edges with two equivalent O(1)Nd3Nb tetrahedra.