K3Li2Nb5O15 crystallizes in the tetragonal P4bm space group. There are two inequivalent K sites. In the first K site, K(1) is bonded to four equivalent O(4) and eight equivalent O(3) atoms to form KO12 cuboctahedra that share faces with two equivalent K(1)O12 cuboctahedra and faces with eight equivalent Nb(2)O6 octahedra. In the second K site, K(2) is bonded in a 9-coordinate geometry to one O(1), two equivalent O(4), two equivalent O(5), and four equivalent O(2) atoms. Li(1) is bonded in a 6-coordinate geometry to one O(1), one O(5), two equivalent O(2), and two equivalent O(4) atoms. There are two inequivalent Nb sites. In the first Nb site, Nb(1) is bonded to two equivalent O(1) and four equivalent O(2) atoms to form distorted corner-sharing NbO6 octahedra. The corner-sharing octahedral tilt angles range from 0-32°. In the second Nb site, Nb(2) is bonded to one O(2), one O(5), two equivalent O(3), and two equivalent O(4) atoms to form distorted NbO6 octahedra that share  a cornercorner with one Nb(1)O6 octahedra, corners with five equivalent Nb(2)O6 octahedra, and faces with two equivalent K(1)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 7-32°. There are five inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to two equivalent K(2), two equivalent Li(1), and two equivalent Nb(1) atoms. In the second O site, O(2) is bonded in a 5-coordinate geometry to two equivalent K(2), one Li(1), one Nb(1), and one Nb(2) atom. In the third O site, O(3) is bonded in a 2-coordinate geometry to two equivalent K(1) and two equivalent Nb(2) atoms. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to one K(1), one K(2), one Li(1), and two equivalent Nb(2) atoms. In the fifth O site, O(5) is bonded in a 5-coordinate geometry to two equivalent K(2), one Li(1), and two equivalent Nb(2) atoms.
K3Li2Nb5O15 crystallizes in the tetragonal P4bm space group. There are two inequivalent K sites. In the first K site, K(1) is bonded to four equivalent O(4) and eight equivalent O(3) atoms to form KO12 cuboctahedra that share faces with two equivalent K(1)O12 cuboctahedra and faces with eight equivalent Nb(2)O6 octahedra. All K(1)-O(4) bond lengths are 2.94 Å. There are four shorter (2.81 Å) and four longer (2.97 Å) K(1)-O(3) bond lengths. In the second K site, K(2) is bonded in a 9-coordinate geometry to one O(1), two equivalent O(4), two equivalent O(5), and four equivalent O(2) atoms. The K(2)-O(1) bond length is 3.10 Å. Both K(2)-O(4) bond lengths are 3.21 Å. There is one shorter (2.83 Å) and one longer (3.11 Å) K(2)-O(5) bond length. There are two shorter (2.91 Å) and two longer (3.23 Å) K(2)-O(2) bond lengths. Li(1) is bonded in a 6-coordinate geometry to one O(1), one O(5), two equivalent O(2), and two equivalent O(4) atoms. The Li(1)-O(1) bond length is 2.27 Å. The Li(1)-O(5) bond length is 2.30 Å. Both Li(1)-O(2) bond lengths are 2.29 Å. Both Li(1)-O(4) bond lengths are 2.14 Å. There are two inequivalent Nb sites. In the first Nb site, Nb(1) is bonded to two equivalent O(1) and four equivalent O(2) atoms to form distorted corner-sharing NbO6 octahedra. The corner-sharing octahedral tilt angles range from 0-32°. There is one shorter (1.87 Å) and one longer (2.30 Å) Nb(1)-O(1) bond length. All Nb(1)-O(2) bond lengths are 1.99 Å. In the second Nb site, Nb(2) is bonded to one O(2), one O(5), two equivalent O(3), and two equivalent O(4) atoms to form distorted NbO6 octahedra that share  a cornercorner with one Nb(1)O6 octahedra, corners with five equivalent Nb(2)O6 octahedra, and faces with two equivalent K(1)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 7-32°. The Nb(2)-O(2) bond length is 2.01 Å. The Nb(2)-O(5) bond length is 2.02 Å. There is one shorter (1.97 Å) and one longer (2.04 Å) Nb(2)-O(3) bond length. There is one shorter (1.86 Å) and one longer (2.32 Å) Nb(2)-O(4) bond length. There are five inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to two equivalent K(2), two equivalent Li(1), and two equivalent Nb(1) atoms. In the second O site, O(2) is bonded in a 5-coordinate geometry to two equivalent K(2), one Li(1), one Nb(1), and one Nb(2) atom. In the third O site, O(3) is bonded in a 2-coordinate geometry to two equivalent K(1) and two equivalent Nb(2) atoms. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to one K(1), one K(2), one Li(1), and two equivalent Nb(2) atoms. In the fifth O site, O(5) is bonded in a 5-coordinate geometry to two equivalent K(2), one Li(1), and two equivalent Nb(2) atoms.