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 O(1), two equivalent O(5), and two equivalent O(8) atoms to form distorted BaO6 pentagonal pyramids that share corners with two equivalent Nb(4)NO5 octahedra, corners with two equivalent Nb(6)NO5 octahedra, and faces with two equivalent Ba(1)O6 pentagonal pyramids. The corner-sharing octahedral tilt angles range from 46-49°. In the second Ba site, Ba(2) is bonded to two equivalent O(12), two equivalent O(14), and two equivalent O(9) atoms to form distorted BaO6 pentagonal pyramids that share corners with two equivalent Nb(4)NO5 octahedra, corners with two equivalent Nb(6)NO5 octahedra, and faces with two equivalent Ba(2)O6 pentagonal pyramids. The corner-sharing octahedral tilt angles range from 64-66°. There are six inequivalent Nb sites. In the first Nb site, Nb(1) is bonded in a 6-coordinate geometry to one N(2), one O(14), one O(4), one O(5), and two equivalent O(2) atoms. In the second Nb site, Nb(2) is bonded to one O(2), one O(3), one O(6), one O(7), and two equivalent O(4) atoms to form distorted NbO6 octahedra that share  a cornercorner with one Nb(4)NO5 octahedra,  a cornercorner with one Nb(6)NO5 octahedra, and corners with two equivalent Nb(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 1-33°. In the third Nb site, Nb(3) is bonded in a 6-coordinate geometry to one O(11), one O(4), one O(5), one O(9), and two equivalent O(7) atoms. In the fourth Nb site, Nb(4) is bonded to one N(1), one O(12), one O(6), one O(8), and two equivalent O(10) atoms to form distorted NbNO5 octahedra that share  a cornercorner with one Nb(2)O6 octahedra, corners with two equivalent Nb(4)NO5 octahedra, corners with two equivalent Ba(1)O6 pentagonal pyramids, corners with two equivalent Ba(2)O6 pentagonal pyramids, and  an edgeedge with one Nb(6)NO5 octahedra. The corner-sharing octahedral tilt angles range from 1-19°. In the fifth Nb site, Nb(5) is bonded in a 6-coordinate geometry to one N(2), two equivalent N(1), one O(10), one O(11), and one O(13) atom. In the sixth Nb site, Nb(6) is bonded to one N(1), one O(1), one O(12), one O(3), and two equivalent O(13) atoms to form distorted NbNO5 octahedra that share  a cornercorner with one Nb(2)O6 octahedra, corners with two equivalent Nb(6)NO5 octahedra, corners with two equivalent Ba(1)O6 pentagonal pyramids, corners with two equivalent Ba(2)O6 pentagonal pyramids, and  an edgeedge with one Nb(4)NO5 octahedra. The corner-sharing octahedral tilt angles range from 10-24°. There are two inequivalent N sites. In the first N site, N(1) is bonded to one Nb(4), one Nb(6), and two equivalent Nb(5) atoms to form distorted NNb4 trigonal pyramids that share corners with two equivalent N(1)Nb4 trigonal pyramids and  an edgeedge with one O(12)Ba2Nb2 tetrahedra. In the second N site, N(2) is bonded in a linear geometry to one Nb(1) and one Nb(5) atom. There are fourteen inequivalent O sites. In the first O site, O(1) is bonded in a distorted single-bond geometry to two equivalent Ba(1) and one Nb(6) atom. In the second O site, O(2) is bonded in a 3-coordinate 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 to one Nb(1), one Nb(3), and two equivalent Nb(2) atoms to form distorted ONb4 trigonal pyramids that share corners with two equivalent O(4)Nb4 trigonal pyramids and  an edgeedge with one O(5)Ba2Nb2 tetrahedra. In the fifth O site, O(5) is bonded to two equivalent Ba(1), one Nb(1), and one Nb(3) atom to form distorted OBa2Nb2 tetrahedra that share corners with two equivalent O(5)Ba2Nb2 tetrahedra and  an edgeedge with one O(4)Nb4 trigonal pyramid. In the sixth O site, O(6) is bonded in a linear geometry to one Nb(2) and one Nb(4) atom. In the seventh O site, O(7) is bonded in a 3-coordinate geometry to one Nb(2) and two equivalent Nb(3) atoms. In the eighth O site, O(8) is bonded in a distorted single-bond geometry to two equivalent Ba(1) and one Nb(4) atom. In the ninth O site, O(9) is bonded in a distorted single-bond geometry to two equivalent Ba(2) and one Nb(3) atom. In the tenth O site, O(10) is bonded in a distorted T-shaped geometry to one Nb(5) and two equivalent Nb(4) atoms. In the eleventh O site, O(11) is bonded in a bent 150 degrees geometry to one Nb(3) and one Nb(5) atom. In the twelfth O site, O(12) is bonded to two equivalent Ba(2), one Nb(4), and one Nb(6) atom to form OBa2Nb2 tetrahedra that share corners with two equivalent O(12)Ba2Nb2 tetrahedra and  an edgeedge with one N(1)Nb4 trigonal pyramid. In the thirteenth O site, O(13) is bonded in a distorted T-shaped geometry to one Nb(5) and two equivalent Nb(6) atoms. In the fourteenth O site, O(14) is bonded in a distorted single-bond 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 O(1), two equivalent O(5), and two equivalent O(8) atoms to form distorted BaO6 pentagonal pyramids that share corners with two equivalent Nb(4)NO5 octahedra, corners with two equivalent Nb(6)NO5 octahedra, and faces with two equivalent Ba(1)O6 pentagonal pyramids. The corner-sharing octahedral tilt angles range from 46-49°. Both Ba(1)-O(1) bond lengths are 2.75 Å. Both Ba(1)-O(5) bond lengths are 2.77 Å. Both Ba(1)-O(8) bond lengths are 2.76 Å. In the second Ba site, Ba(2) is bonded to two equivalent O(12), two equivalent O(14), and two equivalent O(9) atoms to form distorted BaO6 pentagonal pyramids that share corners with two equivalent Nb(4)NO5 octahedra, corners with two equivalent Nb(6)NO5 octahedra, and faces with two equivalent Ba(2)O6 pentagonal pyramids. The corner-sharing octahedral tilt angles range from 64-66°. Both Ba(2)-O(12) bond lengths are 2.76 Å. Both Ba(2)-O(14) bond lengths are 2.71 Å. Both Ba(2)-O(9) bond lengths are 2.70 Å. There are six inequivalent Nb sites. In the first Nb site, Nb(1) is bonded in a 6-coordinate geometry to one N(2), one O(14), one O(4), one O(5), and two equivalent O(2) atoms. The Nb(1)-N(2) bond length is 1.89 Å. The Nb(1)-O(14) bond length is 1.84 Å. The Nb(1)-O(4) bond length is 2.39 Å. The Nb(1)-O(5) bond length is 2.29 Å. Both Nb(1)-O(2) bond lengths are 2.03 Å. In the second Nb site, Nb(2) is bonded to one O(2), one O(3), one O(6), one O(7), and two equivalent O(4) atoms to form distorted NbO6 octahedra that share  a cornercorner with one Nb(4)NO5 octahedra,  a cornercorner with one Nb(6)NO5 octahedra, and corners with two equivalent Nb(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 1-33°. The Nb(2)-O(2) bond length is 2.28 Å. The Nb(2)-O(3) bond length is 1.83 Å. The Nb(2)-O(6) bond length is 1.84 Å. The Nb(2)-O(7) bond length is 2.29 Å. Both Nb(2)-O(4) bond lengths are 2.03 Å. In the third Nb site, Nb(3) is bonded in a 6-coordinate geometry to one O(11), one O(4), one O(5), one O(9), and two equivalent O(7) atoms. The Nb(3)-O(11) bond length is 2.01 Å. The Nb(3)-O(4) bond length is 2.44 Å. The Nb(3)-O(5) bond length is 1.95 Å. The Nb(3)-O(9) bond length is 1.82 Å. Both Nb(3)-O(7) bond lengths are 2.02 Å. In the fourth Nb site, Nb(4) is bonded to one N(1), one O(12), one O(6), one O(8), and two equivalent O(10) atoms to form distorted NbNO5 octahedra that share  a cornercorner with one Nb(2)O6 octahedra, corners with two equivalent Nb(4)NO5 octahedra, corners with two equivalent Ba(1)O6 pentagonal pyramids, corners with two equivalent Ba(2)O6 pentagonal pyramids, and  an edgeedge with one Nb(6)NO5 octahedra. The corner-sharing octahedral tilt angles range from 1-19°. The Nb(4)-N(1) bond length is 2.26 Å. The Nb(4)-O(12) bond length is 2.07 Å. The Nb(4)-O(6) bond length is 2.06 Å. The Nb(4)-O(8) bond length is 1.85 Å. Both Nb(4)-O(10) bond lengths are 1.97 Å. In the fifth Nb site, Nb(5) is bonded in a 6-coordinate geometry to one N(2), two equivalent N(1), one O(10), one O(11), and one O(13) atom. The Nb(5)-N(2) bond length is 1.88 Å. Both Nb(5)-N(1) bond lengths are 2.08 Å. The Nb(5)-O(10) bond length is 2.51 Å. The Nb(5)-O(11) bond length is 1.87 Å. The Nb(5)-O(13) bond length is 2.35 Å. In the sixth Nb site, Nb(6) is bonded to one N(1), one O(1), one O(12), one O(3), and two equivalent O(13) atoms to form distorted NbNO5 octahedra that share  a cornercorner with one Nb(2)O6 octahedra, corners with two equivalent Nb(6)NO5 octahedra, corners with two equivalent Ba(1)O6 pentagonal pyramids, corners with two equivalent Ba(2)O6 pentagonal pyramids, and  an edgeedge with one Nb(4)NO5 octahedra. The corner-sharing octahedral tilt angles range from 10-24°. The Nb(6)-N(1) bond length is 2.24 Å. The Nb(6)-O(1) bond length is 1.85 Å. The Nb(6)-O(12) bond length is 2.03 Å. The Nb(6)-O(3) bond length is 2.09 Å. Both Nb(6)-O(13) bond lengths are 1.99 Å. There are two inequivalent N sites. In the first N site, N(1) is bonded to one Nb(4), one Nb(6), and two equivalent Nb(5) atoms to form distorted NNb4 trigonal pyramids that share corners with two equivalent N(1)Nb4 trigonal pyramids and  an edgeedge with one O(12)Ba2Nb2 tetrahedra. In the second N site, N(2) is bonded in a linear geometry to one Nb(1) and one Nb(5) atom. There are fourteen inequivalent O sites. In the first O site, O(1) is bonded in a distorted single-bond geometry to two equivalent Ba(1) and one Nb(6) atom. In the second O site, O(2) is bonded in a 3-coordinate 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 to one Nb(1), one Nb(3), and two equivalent Nb(2) atoms to form distorted ONb4 trigonal pyramids that share corners with two equivalent O(4)Nb4 trigonal pyramids and  an edgeedge with one O(5)Ba2Nb2 tetrahedra. In the fifth O site, O(5) is bonded to two equivalent Ba(1), one Nb(1), and one Nb(3) atom to form distorted OBa2Nb2 tetrahedra that share corners with two equivalent O(5)Ba2Nb2 tetrahedra and  an edgeedge with one O(4)Nb4 trigonal pyramid. In the sixth O site, O(6) is bonded in a linear geometry to one Nb(2) and one Nb(4) atom. In the seventh O site, O(7) is bonded in a 3-coordinate geometry to one Nb(2) and two equivalent Nb(3) atoms. In the eighth O site, O(8) is bonded in a distorted single-bond geometry to two equivalent Ba(1) and one Nb(4) atom. In the ninth O site, O(9) is bonded in a distorted single-bond geometry to two equivalent Ba(2) and one Nb(3) atom. In the tenth O site, O(10) is bonded in a distorted T-shaped geometry to one Nb(5) and two equivalent Nb(4) atoms. In the eleventh O site, O(11) is bonded in a bent 150 degrees geometry to one Nb(3) and one Nb(5) atom. In the twelfth O site, O(12) is bonded to two equivalent Ba(2), one Nb(4), and one Nb(6) atom to form OBa2Nb2 tetrahedra that share corners with two equivalent O(12)Ba2Nb2 tetrahedra and  an edgeedge with one N(1)Nb4 trigonal pyramid. In the thirteenth O site, O(13) is bonded in a distorted T-shaped geometry to one Nb(5) and two equivalent Nb(6) atoms. In the fourteenth O site, O(14) is bonded in a distorted single-bond geometry to two equivalent Ba(2) and one Nb(1) atom.