BaNb3NO7 crystallizes in the monoclinic Cm space group. There are two inequivalent Ba sites. In the first Ba site, Ba(1) is bonded to two equivalent N(1), two equivalent O(1), and two equivalent O(7) atoms to form distorted BaN2O4 pentagonal pyramids that share corners with two equivalent Nb(4)O6 octahedra and faces with two equivalent Ba(1)N2O4 pentagonal pyramids. The corner-sharing octahedral tilt angles are 47°. In the second Ba site, Ba(2) is bonded to two equivalent O(12), two equivalent O(14), and two equivalent O(8) atoms to form distorted BaO6 pentagonal pyramids that share corners with two equivalent Nb(4)O6 octahedra and faces with two equivalent Ba(2)O6 pentagonal pyramids. The corner-sharing octahedral tilt angles are 67°. There are six inequivalent Nb sites. In the first Nb site, Nb(1) is bonded in a 6-coordinate geometry to one N(1), one O(13), one O(14), one O(4), and two equivalent O(2) atoms. In the second Nb site, Nb(2) is bonded in a 6-coordinate geometry to one O(2), one O(3), one O(5), one O(6), and two equivalent O(4) atoms. In the third Nb site, Nb(3) is bonded in a 6-coordinate geometry to one N(1), one O(10), one O(4), one O(8), and two equivalent O(6) atoms. In the fourth Nb site, Nb(4) is bonded to one O(11), one O(12), one O(5), one O(7), and two equivalent O(9) atoms to form distorted NbO6 octahedra that share corners with two equivalent Nb(4)O6 octahedra, corners with two equivalent Ba(1)N2O4 pentagonal pyramids, and corners with two equivalent Ba(2)O6 pentagonal pyramids. The corner-sharing octahedral tilt angles are 29°. In the fifth Nb site, Nb(5) is bonded in a 6-coordinate geometry to one N(2), one O(10), one O(13), one O(9), and two equivalent O(11) atoms. In the sixth Nb site, Nb(6) is bonded in a 6-coordinate geometry to two equivalent N(2), one O(1), one O(11), one O(12), and one O(3) atom. There are two inequivalent N sites. In the first N site, N(1) is bonded to two equivalent Ba(1), one Nb(1), and one Nb(3) atom to form distorted corner-sharing NBa2Nb2 tetrahedra. In the second N site, N(2) is bonded in a distorted trigonal non-coplanar geometry to one Nb(5) and two equivalent Nb(6) atoms. There are fourteen inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to two equivalent Ba(1) and one Nb(6) atom. In the second O site, O(2) is bonded in a distorted trigonal non-coplanar geometry to one Nb(2) and two equivalent Nb(1) atoms. In the third O site, O(3) is bonded in a linear geometry to one Nb(2) and one Nb(6) atom. In the fourth O site, O(4) is bonded in a 4-coordinate geometry to one Nb(1), one Nb(3), and two equivalent Nb(2) atoms. In the fifth O site, O(5) is bonded in a linear geometry to one Nb(2) and one Nb(4) atom. In the sixth O site, O(6) is bonded in a 3-coordinate geometry to one Nb(2) and two equivalent Nb(3) atoms. In the seventh O site, O(7) is bonded in a distorted single-bond geometry to two equivalent Ba(1) and one Nb(4) atom. In the eighth O site, O(8) is bonded in a distorted single-bond geometry to two equivalent Ba(2) and one Nb(3) atom. In the ninth O site, O(9) is bonded in a distorted bent 150 degrees geometry to one Nb(5) and two equivalent Nb(4) atoms. In the tenth O site, O(10) is bonded in a linear geometry to one Nb(3) and one Nb(5) atom. In the eleventh O site, O(11) is bonded to one Nb(4), one Nb(6), and two equivalent Nb(5) atoms to form distorted ONb4 trigonal pyramids that share corners with two equivalent O(11)Nb4 trigonal pyramids and  an edgeedge with one O(12)Ba2Nb2 tetrahedra. In the twelfth O site, O(12) is bonded to two equivalent Ba(2), one Nb(4), and one Nb(6) atom to form distorted OBa2Nb2 tetrahedra that share corners with two equivalent O(12)Ba2Nb2 tetrahedra and  an edgeedge with one O(11)Nb4 trigonal pyramid. In the thirteenth O site, O(13) is bonded in a linear geometry to one Nb(1) and one Nb(5) atom. In the fourteenth O site, O(14) is bonded in a 3-coordinate geometry to two equivalent Ba(2) and one Nb(1) atom.
BaNb3NO7 crystallizes in the monoclinic Cm space group. There are two inequivalent Ba sites. In the first Ba site, Ba(1) is bonded to two equivalent N(1), two equivalent O(1), and two equivalent O(7) atoms to form distorted BaN2O4 pentagonal pyramids that share corners with two equivalent Nb(4)O6 octahedra and faces with two equivalent Ba(1)N2O4 pentagonal pyramids. The corner-sharing octahedral tilt angles are 47°. Both Ba(1)-N(1) bond lengths are 2.84 Å. Both Ba(1)-O(1) bond lengths are 2.71 Å. Both Ba(1)-O(7) bond lengths are 2.78 Å. In the second Ba site, Ba(2) is bonded to two equivalent O(12), two equivalent O(14), and two equivalent O(8) atoms to form distorted BaO6 pentagonal pyramids that share corners with two equivalent Nb(4)O6 octahedra and faces with two equivalent Ba(2)O6 pentagonal pyramids. The corner-sharing octahedral tilt angles are 67°. Both Ba(2)-O(12) bond lengths are 2.81 Å. Both Ba(2)-O(14) bond lengths are 2.69 Å. Both Ba(2)-O(8) bond lengths are 2.77 Å. There are six inequivalent Nb sites. In the first Nb site, Nb(1) is bonded in a 6-coordinate geometry to one N(1), one O(13), one O(14), one O(4), and two equivalent O(2) atoms. The Nb(1)-N(1) bond length is 1.93 Å. The Nb(1)-O(13) bond length is 2.21 Å. The Nb(1)-O(14) bond length is 1.85 Å. The Nb(1)-O(4) bond length is 2.41 Å. Both Nb(1)-O(2) bond lengths are 2.04 Å. In the second Nb site, Nb(2) is bonded in a 6-coordinate geometry to one O(2), one O(3), one O(5), one O(6), and two equivalent O(4) atoms. The Nb(2)-O(2) bond length is 2.27 Å. The Nb(2)-O(3) bond length is 1.83 Å. The Nb(2)-O(5) bond length is 1.85 Å. The Nb(2)-O(6) bond length is 2.38 Å. Both Nb(2)-O(4) bond lengths are 2.02 Å. In the third Nb site, Nb(3) is bonded in a 6-coordinate geometry to one N(1), one O(10), one O(4), one O(8), and two equivalent O(6) atoms. The Nb(3)-N(1) bond length is 2.04 Å. The Nb(3)-O(10) bond length is 2.04 Å. The Nb(3)-O(4) bond length is 2.51 Å. The Nb(3)-O(8) bond length is 1.84 Å. Both Nb(3)-O(6) bond lengths are 2.03 Å. In the fourth Nb site, Nb(4) is bonded to one O(11), one O(12), one O(5), one O(7), and two equivalent O(9) atoms to form distorted NbO6 octahedra that share corners with two equivalent Nb(4)O6 octahedra, corners with two equivalent Ba(1)N2O4 pentagonal pyramids, and corners with two equivalent Ba(2)O6 pentagonal pyramids. The corner-sharing octahedral tilt angles are 29°. The Nb(4)-O(11) bond length is 2.42 Å. The Nb(4)-O(12) bond length is 2.01 Å. The Nb(4)-O(5) bond length is 2.05 Å. The Nb(4)-O(7) bond length is 1.82 Å. Both Nb(4)-O(9) bond lengths are 2.00 Å. In the fifth Nb site, Nb(5) is bonded in a 6-coordinate geometry to one N(2), one O(10), one O(13), one O(9), and two equivalent O(11) atoms. The Nb(5)-N(2) bond length is 2.20 Å. The Nb(5)-O(10) bond length is 1.91 Å. The Nb(5)-O(13) bond length is 1.81 Å. The Nb(5)-O(9) bond length is 2.50 Å. Both Nb(5)-O(11) bond lengths are 2.03 Å. In the sixth Nb site, Nb(6) is bonded in a 6-coordinate geometry to two equivalent N(2), one O(1), one O(11), one O(12), and one O(3) atom. Both Nb(6)-N(2) bond lengths are 2.03 Å. The Nb(6)-O(1) bond length is 1.84 Å. The Nb(6)-O(11) bond length is 2.47 Å. The Nb(6)-O(12) bond length is 2.11 Å. The Nb(6)-O(3) bond length is 2.10 Å. There are two inequivalent N sites. In the first N site, N(1) is bonded to two equivalent Ba(1), one Nb(1), and one Nb(3) atom to form distorted corner-sharing NBa2Nb2 tetrahedra. In the second N site, N(2) is bonded in a distorted trigonal non-coplanar geometry to one Nb(5) and two equivalent Nb(6) atoms. There are fourteen inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to two equivalent Ba(1) and one Nb(6) atom. In the second O site, O(2) is bonded in a distorted trigonal non-coplanar geometry to one Nb(2) and two equivalent Nb(1) atoms. In the third O site, O(3) is bonded in a linear geometry to one Nb(2) and one Nb(6) atom. In the fourth O site, O(4) is bonded in a 4-coordinate geometry to one Nb(1), one Nb(3), and two equivalent Nb(2) atoms. In the fifth O site, O(5) is bonded in a linear geometry to one Nb(2) and one Nb(4) atom. In the sixth O site, O(6) is bonded in a 3-coordinate geometry to one Nb(2) and two equivalent Nb(3) atoms. In the seventh O site, O(7) is bonded in a distorted single-bond geometry to two equivalent Ba(1) and one Nb(4) atom. In the eighth O site, O(8) is bonded in a distorted single-bond geometry to two equivalent Ba(2) and one Nb(3) atom. In the ninth O site, O(9) is bonded in a distorted bent 150 degrees geometry to one Nb(5) and two equivalent Nb(4) atoms. In the tenth O site, O(10) is bonded in a linear geometry to one Nb(3) and one Nb(5) atom. In the eleventh O site, O(11) is bonded to one Nb(4), one Nb(6), and two equivalent Nb(5) atoms to form distorted ONb4 trigonal pyramids that share corners with two equivalent O(11)Nb4 trigonal pyramids and  an edgeedge with one O(12)Ba2Nb2 tetrahedra. In the twelfth O site, O(12) is bonded to two equivalent Ba(2), one Nb(4), and one Nb(6) atom to form distorted OBa2Nb2 tetrahedra that share corners with two equivalent O(12)Ba2Nb2 tetrahedra and  an edgeedge with one O(11)Nb4 trigonal pyramid. In the thirteenth O site, O(13) is bonded in a linear geometry to one Nb(1) and one Nb(5) atom. In the fourteenth O site, O(14) is bonded in a 3-coordinate geometry to two equivalent Ba(2) and one Nb(1) atom.