Li6NbFe5O12 is Caswellsilverite-derived structured and crystallizes in the monoclinic Cm space group. There are four inequivalent Li sites. In the first Li site, Li(1) is bonded to one O(6), one O(8), two equivalent O(1), and two equivalent O(3) atoms to form distorted LiO6 octahedra that share  a cornercorner with one Nb(1)O6 octahedra, corners with two equivalent Fe(1)O6 octahedra, corners with three equivalent Fe(2)O6 octahedra, corners with three equivalent Fe(3)O6 octahedra,  an edgeedge with one Nb(1)O6 octahedra, edges with two equivalent Fe(1)O6 octahedra, edges with three equivalent Li(1)O6 octahedra, edges with three equivalent Li(4)O6 octahedra, and  a faceface with one Fe(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 5-54°. In the second Li site, Li(2) is bonded to one O(4), one O(7), two equivalent O(2), and two equivalent O(5) atoms to form distorted LiO6 octahedra that share  a cornercorner with one Nb(1)O6 octahedra, corners with two equivalent Fe(1)O6 octahedra, corners with three equivalent Fe(2)O6 octahedra, corners with three equivalent Fe(3)O6 octahedra,  an edgeedge with one Nb(1)O6 octahedra, edges with two equivalent Fe(1)O6 octahedra, edges with three equivalent Li(2)O6 octahedra, edges with three equivalent Li(3)O6 octahedra, and  a faceface with one Fe(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 4-53°. In the third Li site, Li(3) is bonded to one O(4), one O(7), two equivalent O(2), and two equivalent O(5) atoms to form distorted LiO6 octahedra that share  a cornercorner with one Nb(1)O6 octahedra, corners with two equivalent Fe(1)O6 octahedra, corners with six equivalent Fe(3)O6 octahedra,  an edgeedge with one Nb(1)O6 octahedra, edges with two equivalent Fe(1)O6 octahedra, edges with six equivalent Li(2)O6 octahedra, and  a faceface with one Fe(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 5-52°. In the fourth Li site, Li(4) is bonded to one O(6), one O(8), two equivalent O(1), and two equivalent O(3) atoms to form distorted LiO6 octahedra that share  a cornercorner with one Nb(1)O6 octahedra, corners with two equivalent Fe(1)O6 octahedra, corners with six equivalent Fe(3)O6 octahedra,  an edgeedge with one Nb(1)O6 octahedra, edges with two equivalent Fe(1)O6 octahedra, edges with six equivalent Li(1)O6 octahedra, and  a faceface with one Fe(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 5-51°. Nb(1) is bonded to one O(6), one O(7), two equivalent O(1), and two equivalent O(2) atoms to form NbO6 octahedra that share  a cornercorner with one Li(3)O6 octahedra,  a cornercorner with one Li(4)O6 octahedra, corners with two equivalent Li(1)O6 octahedra, corners with two equivalent Li(2)O6 octahedra,  an edgeedge with one Li(3)O6 octahedra,  an edgeedge with one Li(4)O6 octahedra, edges with two equivalent Li(1)O6 octahedra, edges with two equivalent Li(2)O6 octahedra, and edges with six equivalent Fe(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 4-7°. There are three inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(6), one O(7), two equivalent O(1), and two equivalent O(2) atoms to form FeO6 octahedra that share  a cornercorner with one Li(3)O6 octahedra,  a cornercorner with one Li(4)O6 octahedra, corners with two equivalent Li(1)O6 octahedra, corners with two equivalent Li(2)O6 octahedra,  an edgeedge with one Li(3)O6 octahedra,  an edgeedge with one Li(4)O6 octahedra, edges with two equivalent Li(1)O6 octahedra, edges with two equivalent Li(2)O6 octahedra, edges with three equivalent Nb(1)O6 octahedra, and edges with three equivalent Fe(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 5-10°. In the second Fe site, Fe(2) is bonded to one O(4), one O(8), two equivalent O(3), and two equivalent O(5) atoms to form FeO6 octahedra that share corners with six equivalent Li(1)O6 octahedra, corners with six equivalent Li(2)O6 octahedra, edges with six equivalent Fe(3)O6 octahedra,  a faceface with one Li(3)O6 octahedra, and  a faceface with one Li(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 43-54°. In the third Fe site, Fe(3) is bonded to one O(4), one O(8), two equivalent O(3), and two equivalent O(5) atoms to form FeO6 octahedra that share corners with three equivalent Li(1)O6 octahedra, corners with three equivalent Li(2)O6 octahedra, corners with three equivalent Li(3)O6 octahedra, corners with three equivalent Li(4)O6 octahedra, edges with three equivalent Fe(2)O6 octahedra, edges with three equivalent Fe(3)O6 octahedra,  a faceface with one Li(1)O6 octahedra, and  a faceface with one Li(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 41-53°. There are eight inequivalent O sites. In the first O site, O(8) is bonded in a 6-coordinate geometry to one Li(4), two equivalent Li(1), one Fe(2), and two equivalent Fe(3) atoms. In the second O site, O(1) is bonded to one Li(4), two equivalent Li(1), one Nb(1), and two equivalent Fe(1) atoms to form a mixture of edge and corner-sharing OLi3NbFe2 octahedra. The corner-sharing octahedral tilt angles range from 4-7°. In the third O site, O(2) is bonded to one Li(3), two equivalent Li(2), one Nb(1), and two equivalent Fe(1) atoms to form a mixture of edge and corner-sharing OLi3NbFe2 octahedra. The corner-sharing octahedral tilt angles range from 4-7°. In the fourth O site, O(3) is bonded in a 6-coordinate geometry to one Li(4), two equivalent Li(1), one Fe(2), and two equivalent Fe(3) atoms. In the fifth O site, O(4) is bonded in a 6-coordinate geometry to one Li(3), two equivalent Li(2), one Fe(2), and two equivalent Fe(3) atoms. In the sixth O site, O(5) is bonded in a 6-coordinate geometry to one Li(3), two equivalent Li(2), one Fe(2), and two equivalent Fe(3) atoms. In the seventh O site, O(6) is bonded to one Li(4), two equivalent Li(1), one Nb(1), and two equivalent Fe(1) atoms to form a mixture of edge and corner-sharing OLi3NbFe2 octahedra. The corner-sharing octahedral tilt angles range from 4-8°. In the eighth O site, O(7) is bonded to one Li(3), two equivalent Li(2), one Nb(1), and two equivalent Fe(1) atoms to form a mixture of edge and corner-sharing OLi3NbFe2 octahedra. The corner-sharing octahedral tilt angles range from 6-8°.
Li6NbFe5O12 is Caswellsilverite-derived structured and crystallizes in the monoclinic Cm space group. There are four inequivalent Li sites. In the first Li site, Li(1) is bonded to one O(6), one O(8), two equivalent O(1), and two equivalent O(3) atoms to form distorted LiO6 octahedra that share  a cornercorner with one Nb(1)O6 octahedra, corners with two equivalent Fe(1)O6 octahedra, corners with three equivalent Fe(2)O6 octahedra, corners with three equivalent Fe(3)O6 octahedra,  an edgeedge with one Nb(1)O6 octahedra, edges with two equivalent Fe(1)O6 octahedra, edges with three equivalent Li(1)O6 octahedra, edges with three equivalent Li(4)O6 octahedra, and  a faceface with one Fe(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 5-54°. The Li(1)-O(6) bond length is 2.12 Å. The Li(1)-O(8) bond length is 2.42 Å. There is one shorter (2.17 Å) and one longer (2.24 Å) Li(1)-O(1) bond length. There is one shorter (2.07 Å) and one longer (2.29 Å) Li(1)-O(3) bond length. In the second Li site, Li(2) is bonded to one O(4), one O(7), two equivalent O(2), and two equivalent O(5) atoms to form distorted LiO6 octahedra that share  a cornercorner with one Nb(1)O6 octahedra, corners with two equivalent Fe(1)O6 octahedra, corners with three equivalent Fe(2)O6 octahedra, corners with three equivalent Fe(3)O6 octahedra,  an edgeedge with one Nb(1)O6 octahedra, edges with two equivalent Fe(1)O6 octahedra, edges with three equivalent Li(2)O6 octahedra, edges with three equivalent Li(3)O6 octahedra, and  a faceface with one Fe(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 4-53°. The Li(2)-O(4) bond length is 2.45 Å. The Li(2)-O(7) bond length is 2.17 Å. There is one shorter (2.12 Å) and one longer (2.20 Å) Li(2)-O(2) bond length. There is one shorter (2.09 Å) and one longer (2.37 Å) Li(2)-O(5) bond length. In the third Li site, Li(3) is bonded to one O(4), one O(7), two equivalent O(2), and two equivalent O(5) atoms to form distorted LiO6 octahedra that share  a cornercorner with one Nb(1)O6 octahedra, corners with two equivalent Fe(1)O6 octahedra, corners with six equivalent Fe(3)O6 octahedra,  an edgeedge with one Nb(1)O6 octahedra, edges with two equivalent Fe(1)O6 octahedra, edges with six equivalent Li(2)O6 octahedra, and  a faceface with one Fe(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 5-52°. The Li(3)-O(4) bond length is 2.08 Å. The Li(3)-O(7) bond length is 2.39 Å. Both Li(3)-O(2) bond lengths are 2.11 Å. Both Li(3)-O(5) bond lengths are 2.30 Å. In the fourth Li site, Li(4) is bonded to one O(6), one O(8), two equivalent O(1), and two equivalent O(3) atoms to form distorted LiO6 octahedra that share  a cornercorner with one Nb(1)O6 octahedra, corners with two equivalent Fe(1)O6 octahedra, corners with six equivalent Fe(3)O6 octahedra,  an edgeedge with one Nb(1)O6 octahedra, edges with two equivalent Fe(1)O6 octahedra, edges with six equivalent Li(1)O6 octahedra, and  a faceface with one Fe(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 5-51°. The Li(4)-O(6) bond length is 2.25 Å. The Li(4)-O(8) bond length is 2.13 Å. Both Li(4)-O(1) bond lengths are 2.14 Å. Both Li(4)-O(3) bond lengths are 2.38 Å. Nb(1) is bonded to one O(6), one O(7), two equivalent O(1), and two equivalent O(2) atoms to form NbO6 octahedra that share  a cornercorner with one Li(3)O6 octahedra,  a cornercorner with one Li(4)O6 octahedra, corners with two equivalent Li(1)O6 octahedra, corners with two equivalent Li(2)O6 octahedra,  an edgeedge with one Li(3)O6 octahedra,  an edgeedge with one Li(4)O6 octahedra, edges with two equivalent Li(1)O6 octahedra, edges with two equivalent Li(2)O6 octahedra, and edges with six equivalent Fe(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 4-7°. The Nb(1)-O(6) bond length is 2.00 Å. The Nb(1)-O(7) bond length is 2.12 Å. Both Nb(1)-O(1) bond lengths are 2.06 Å. Both Nb(1)-O(2) bond lengths are 2.01 Å. There are three inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(6), one O(7), two equivalent O(1), and two equivalent O(2) atoms to form FeO6 octahedra that share  a cornercorner with one Li(3)O6 octahedra,  a cornercorner with one Li(4)O6 octahedra, corners with two equivalent Li(1)O6 octahedra, corners with two equivalent Li(2)O6 octahedra,  an edgeedge with one Li(3)O6 octahedra,  an edgeedge with one Li(4)O6 octahedra, edges with two equivalent Li(1)O6 octahedra, edges with two equivalent Li(2)O6 octahedra, edges with three equivalent Nb(1)O6 octahedra, and edges with three equivalent Fe(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 5-10°. The Fe(1)-O(6) bond length is 2.17 Å. The Fe(1)-O(7) bond length is 2.08 Å. There is one shorter (2.09 Å) and one longer (2.19 Å) Fe(1)-O(1) bond length. There is one shorter (2.18 Å) and one longer (2.19 Å) Fe(1)-O(2) bond length. In the second Fe site, Fe(2) is bonded to one O(4), one O(8), two equivalent O(3), and two equivalent O(5) atoms to form FeO6 octahedra that share corners with six equivalent Li(1)O6 octahedra, corners with six equivalent Li(2)O6 octahedra, edges with six equivalent Fe(3)O6 octahedra,  a faceface with one Li(3)O6 octahedra, and  a faceface with one Li(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 43-54°. The Fe(2)-O(4) bond length is 2.08 Å. The Fe(2)-O(8) bond length is 2.06 Å. Both Fe(2)-O(3) bond lengths are 2.07 Å. Both Fe(2)-O(5) bond lengths are 2.09 Å. In the third Fe site, Fe(3) is bonded to one O(4), one O(8), two equivalent O(3), and two equivalent O(5) atoms to form FeO6 octahedra that share corners with three equivalent Li(1)O6 octahedra, corners with three equivalent Li(2)O6 octahedra, corners with three equivalent Li(3)O6 octahedra, corners with three equivalent Li(4)O6 octahedra, edges with three equivalent Fe(2)O6 octahedra, edges with three equivalent Fe(3)O6 octahedra,  a faceface with one Li(1)O6 octahedra, and  a faceface with one Li(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 41-53°. The Fe(3)-O(4) bond length is 2.05 Å. The Fe(3)-O(8) bond length is 2.07 Å. There is one shorter (2.07 Å) and one longer (2.10 Å) Fe(3)-O(3) bond length. There is one shorter (2.08 Å) and one longer (2.09 Å) Fe(3)-O(5) bond length. There are eight inequivalent O sites. In the first O site, O(8) is bonded in a 6-coordinate geometry to one Li(4), two equivalent Li(1), one Fe(2), and two equivalent Fe(3) atoms. In the second O site, O(1) is bonded to one Li(4), two equivalent Li(1), one Nb(1), and two equivalent Fe(1) atoms to form a mixture of edge and corner-sharing OLi3NbFe2 octahedra. The corner-sharing octahedral tilt angles range from 4-7°. In the third O site, O(2) is bonded to one Li(3), two equivalent Li(2), one Nb(1), and two equivalent Fe(1) atoms to form a mixture of edge and corner-sharing OLi3NbFe2 octahedra. The corner-sharing octahedral tilt angles range from 4-7°. In the fourth O site, O(3) is bonded in a 6-coordinate geometry to one Li(4), two equivalent Li(1), one Fe(2), and two equivalent Fe(3) atoms. In the fifth O site, O(4) is bonded in a 6-coordinate geometry to one Li(3), two equivalent Li(2), one Fe(2), and two equivalent Fe(3) atoms. In the sixth O site, O(5) is bonded in a 6-coordinate geometry to one Li(3), two equivalent Li(2), one Fe(2), and two equivalent Fe(3) atoms. In the seventh O site, O(6) is bonded to one Li(4), two equivalent Li(1), one Nb(1), and two equivalent Fe(1) atoms to form a mixture of edge and corner-sharing OLi3NbFe2 octahedra. The corner-sharing octahedral tilt angles range from 4-8°. In the eighth O site, O(7) is bonded to one Li(3), two equivalent Li(2), one Nb(1), and two equivalent Fe(1) atoms to form a mixture of edge and corner-sharing OLi3NbFe2 octahedra. The corner-sharing octahedral tilt angles range from 6-8°.