Ba3NiNb2O9 is (Cubic) Perovskite-derived structured and crystallizes in the monoclinic P2_1/m space group. There are six inequivalent Ba sites. In the first Ba site, Ba(1) is bonded to one O(8), one O(9), two equivalent O(1), two equivalent O(10), two equivalent O(13), two equivalent O(3), and two equivalent O(4) atoms to form BaO12 cuboctahedra that share  a cornercorner with one Ba(5)O12 cuboctahedra, corners with two equivalent Ba(2)O12 cuboctahedra, corners with two equivalent Ba(3)O12 cuboctahedra, corners with three equivalent Ba(6)O12 cuboctahedra, corners with four equivalent Ba(1)O12 cuboctahedra,  a faceface with one Ba(5)O12 cuboctahedra, faces with two equivalent Ba(3)O12 cuboctahedra, faces with three equivalent Ba(6)O12 cuboctahedra,  a faceface with one Nb(3)O6 octahedra, faces with two equivalent Nb(1)O6 octahedra, faces with two equivalent Ni(2)O6 octahedra, and faces with three equivalent Nb(4)O6 octahedra. In the second Ba site, Ba(2) is bonded to one O(6), one O(7), two equivalent O(1), two equivalent O(11), two equivalent O(12), two equivalent O(2), and two equivalent O(5) atoms to form BaO12 cuboctahedra that share  a cornercorner with one Ba(3)O12 cuboctahedra, corners with two equivalent Ba(1)O12 cuboctahedra, corners with two equivalent Ba(5)O12 cuboctahedra, corners with three equivalent Ba(4)O12 cuboctahedra, corners with four equivalent Ba(2)O12 cuboctahedra,  a faceface with one Ba(3)O12 cuboctahedra, faces with two equivalent Ba(5)O12 cuboctahedra, faces with three equivalent Ba(4)O12 cuboctahedra,  a faceface with one Nb(1)O6 octahedra, faces with two equivalent Nb(3)O6 octahedra, faces with two equivalent Ni(1)O6 octahedra, and faces with three equivalent Nb(2)O6 octahedra. In the third Ba site, Ba(3) is bonded to one O(4), one O(6), two equivalent O(1), two equivalent O(10), two equivalent O(12), two equivalent O(13), and two equivalent O(8) atoms to form BaO12 cuboctahedra that share  a cornercorner with one Ba(2)O12 cuboctahedra, corners with two equivalent Ba(1)O12 cuboctahedra, corners with two equivalent Ba(3)O12 cuboctahedra, corners with two equivalent Ba(4)O12 cuboctahedra, corners with two equivalent Ba(5)O12 cuboctahedra, corners with three equivalent Ba(6)O12 cuboctahedra,  a faceface with one Ba(2)O12 cuboctahedra,  a faceface with one Ba(6)O12 cuboctahedra, faces with two equivalent Ba(1)O12 cuboctahedra, faces with two equivalent Ba(5)O12 cuboctahedra,  a faceface with one Nb(4)O6 octahedra,  a faceface with one Ni(1)O6 octahedra, faces with two equivalent Nb(1)O6 octahedra, faces with two equivalent Nb(3)O6 octahedra, and faces with two equivalent Ni(2)O6 octahedra. In the fourth Ba site, Ba(4) is bonded to one O(5), two equivalent O(12), two equivalent O(2), three equivalent O(7), and four equivalent O(11) atoms to form BaO12 cuboctahedra that share corners with two equivalent Ba(3)O12 cuboctahedra, corners with three equivalent Ba(2)O12 cuboctahedra, corners with three equivalent Ba(5)O12 cuboctahedra, corners with four equivalent Ba(4)O12 cuboctahedra,  a faceface with one Ba(5)O12 cuboctahedra, faces with two equivalent Ba(4)O12 cuboctahedra, faces with three equivalent Ba(2)O12 cuboctahedra,  a faceface with one Nb(3)O6 octahedra, faces with three equivalent Ni(1)O6 octahedra, and faces with four equivalent Nb(2)O6 octahedra. In the fifth Ba site, Ba(5) is bonded to one O(5), one O(8), two equivalent O(1), two equivalent O(10), two equivalent O(11), two equivalent O(12), and two equivalent O(6) atoms to form BaO12 cuboctahedra that share  a cornercorner with one Ba(1)O12 cuboctahedra, corners with two equivalent Ba(2)O12 cuboctahedra, corners with two equivalent Ba(3)O12 cuboctahedra, corners with two equivalent Ba(5)O12 cuboctahedra, corners with two equivalent Ba(6)O12 cuboctahedra, corners with three equivalent Ba(4)O12 cuboctahedra,  a faceface with one Ba(1)O12 cuboctahedra,  a faceface with one Ba(4)O12 cuboctahedra, faces with two equivalent Ba(2)O12 cuboctahedra, faces with two equivalent Ba(3)O12 cuboctahedra,  a faceface with one Nb(2)O6 octahedra,  a faceface with one Ni(2)O6 octahedra, faces with two equivalent Nb(1)O6 octahedra, faces with two equivalent Nb(3)O6 octahedra, and faces with two equivalent Ni(1)O6 octahedra. In the sixth Ba site, Ba(6) is bonded to one O(4), two equivalent O(10), two equivalent O(3), three equivalent O(9), and four equivalent O(13) atoms to form BaO12 cuboctahedra that share corners with two equivalent Ba(5)O12 cuboctahedra, corners with three equivalent Ba(1)O12 cuboctahedra, corners with three equivalent Ba(3)O12 cuboctahedra, corners with four equivalent Ba(6)O12 cuboctahedra,  a faceface with one Ba(3)O12 cuboctahedra, faces with two equivalent Ba(6)O12 cuboctahedra, faces with three equivalent Ba(1)O12 cuboctahedra,  a faceface with one Nb(1)O6 octahedra, faces with three equivalent Ni(2)O6 octahedra, and faces with four equivalent Nb(4)O6 octahedra. There are four inequivalent Nb sites. In the first Nb site, Nb(1) is bonded to one O(4), one O(6), two equivalent O(1), and two equivalent O(10) atoms to form NbO6 octahedra that share  a cornercorner with one Nb(4)O6 octahedra,  a cornercorner with one Ni(1)O6 octahedra, corners with two equivalent Nb(3)O6 octahedra, corners with two equivalent Ni(2)O6 octahedra,  a faceface with one Ba(2)O12 cuboctahedra,  a faceface with one Ba(6)O12 cuboctahedra, faces with two equivalent Ba(1)O12 cuboctahedra, faces with two equivalent Ba(3)O12 cuboctahedra, and faces with two equivalent Ba(5)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 0-3°. In the second Nb site, Nb(2) is bonded to one O(5), one O(7), two equivalent O(11), and two equivalent O(2) atoms to form NbO6 octahedra that share  a cornercorner with one Nb(3)O6 octahedra, corners with two equivalent Nb(2)O6 octahedra, corners with three equivalent Ni(1)O6 octahedra,  a faceface with one Ba(5)O12 cuboctahedra, faces with three equivalent Ba(2)O12 cuboctahedra, and faces with four equivalent Ba(4)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 0-3°. In the third Nb site, Nb(3) is bonded to one O(5), one O(8), two equivalent O(1), and two equivalent O(12) atoms to form NbO6 octahedra that share  a cornercorner with one Nb(2)O6 octahedra,  a cornercorner with one Ni(2)O6 octahedra, corners with two equivalent Nb(1)O6 octahedra, corners with two equivalent Ni(1)O6 octahedra,  a faceface with one Ba(1)O12 cuboctahedra,  a faceface with one Ba(4)O12 cuboctahedra, faces with two equivalent Ba(2)O12 cuboctahedra, faces with two equivalent Ba(3)O12 cuboctahedra, and faces with two equivalent Ba(5)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 0-3°. In the fourth Nb site, Nb(4) is bonded to one O(4), one O(9), two equivalent O(13), and two equivalent O(3) atoms to form NbO6 octahedra that share  a cornercorner with one Nb(1)O6 octahedra, corners with two equivalent Nb(4)O6 octahedra, corners with three equivalent Ni(2)O6 octahedra,  a faceface with one Ba(3)O12 cuboctahedra, faces with three equivalent Ba(1)O12 cuboctahedra, and faces with four equivalent Ba(6)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 0-3°. There are two inequivalent Ni sites. In the first Ni site, Ni(1) is bonded to one O(6), one O(7), two equivalent O(11), and two equivalent O(12) atoms to form NiO6 octahedra that share  a cornercorner with one Nb(1)O6 octahedra, corners with two equivalent Nb(3)O6 octahedra, corners with three equivalent Nb(2)O6 octahedra,  a faceface with one Ba(3)O12 cuboctahedra, faces with two equivalent Ba(2)O12 cuboctahedra, faces with two equivalent Ba(5)O12 cuboctahedra, and faces with three equivalent Ba(4)O12 cuboctahedra. The corner-sharing octahedral tilt angles are 3°. In the second Ni site, Ni(2) is bonded to one O(8), one O(9), two equivalent O(10), and two equivalent O(13) atoms to form NiO6 octahedra that share  a cornercorner with one Nb(3)O6 octahedra, corners with two equivalent Nb(1)O6 octahedra, corners with three equivalent Nb(4)O6 octahedra,  a faceface with one Ba(5)O12 cuboctahedra, faces with two equivalent Ba(1)O12 cuboctahedra, faces with two equivalent Ba(3)O12 cuboctahedra, and faces with three equivalent Ba(6)O12 cuboctahedra. The corner-sharing octahedral tilt angles are 3°. There are thirteen inequivalent O sites. In the first O site, O(1) is bonded to one Ba(1), one Ba(2), one Ba(3), one Ba(5), one Nb(1), and one Nb(3) atom to form distorted OBa4Nb2 octahedra that share  a cornercorner with one O(4)Ba4Nb2 octahedra,  a cornercorner with one O(5)Ba4Nb2 octahedra,  a cornercorner with one O(9)Ba4NbNi octahedra, corners with two equivalent O(2)Ba4Nb2 octahedra, corners with two equivalent O(3)Ba4Nb2 octahedra, corners with two equivalent O(13)Ba4NbNi octahedra, corners with two equivalent O(6)Ba4NbNi octahedra, corners with three equivalent O(12)Ba4NbNi octahedra,  an edgeedge with one O(12)Ba4NbNi octahedra,  an edgeedge with one O(13)Ba4NbNi octahedra,  a faceface with one O(4)Ba4Nb2 octahedra,  a faceface with one O(5)Ba4Nb2 octahedra,  a faceface with one O(12)Ba4NbNi octahedra,  a faceface with one O(6)Ba4NbNi octahedra, and faces with two equivalent O(1)Ba4Nb2 octahedra. The corner-sharing octahedral tilt angles range from 0-62°. In the second O site, O(2) is bonded to two equivalent Ba(2), two equivalent Ba(4), and two equivalent Nb(2) atoms to form distorted OBa4Nb2 octahedra that share corners with two equivalent O(5)Ba4Nb2 octahedra, corners with two equivalent O(6)Ba4NbNi octahedra, corners with four equivalent O(1)Ba4Nb2 octahedra, corners with four equivalent O(12)Ba4NbNi octahedra, edges with two equivalent O(12)Ba4NbNi octahedra, faces with two equivalent O(2)Ba4Nb2 octahedra, and faces with two equivalent O(5)Ba4Nb2 octahedra. The corner-sharing octahedral tilt angles range from 0-62°. In the third O site, O(3) is bonded to two equivalent Ba(1), two equivalent Ba(6), and two equivalent Nb(4) atoms to form distorted OBa4Nb2 octahedra that share corners with two equivalent O(4)Ba4Nb2 octahedra, corners with four equivalent O(1)Ba4Nb2 octahedra, corners with four equivalent O(9)Ba4NbNi octahedra, corners with six equivalent O(13)Ba4NbNi octahedra, edges with two equivalent O(13)Ba4NbNi octahedra, faces with two equivalent O(3)Ba4Nb2 octahedra, faces with two equivalent O(4)Ba4Nb2 octahedra, faces with two equivalent O(13)Ba4NbNi octahedra, and faces with two equivalent O(9)Ba4NbNi octahedra. The corner-sharing octahedral tilt angles range from 0-62°. In the fourth O site, O(4) is bonded to one Ba(3), one Ba(6), two equivalent Ba(1), one Nb(1), and one Nb(4) atom to form distorted OBa4Nb2 octahedra that share corners with two equivalent O(1)Ba4Nb2 octahedra, corners with two equivalent O(3)Ba4Nb2 octahedra, corners with two equivalent O(4)Ba4Nb2 octahedra, corners with two equivalent O(12)Ba4NbNi octahedra, corners with two equivalent O(6)Ba4NbNi octahedra, corners with two equivalent O(9)Ba4NbNi octahedra, corners with six equivalent O(13)Ba4NbNi octahedra, edges with two equivalent O(9)Ba4NbNi octahedra, faces with two equivalent O(1)Ba4Nb2 octahedra, faces with two equivalent O(3)Ba4Nb2 octahedra, and faces with two equivalent O(13)Ba4NbNi octahedra. The corner-sharing octahedral tilt angles range from 0-62°. In the fifth O site, O(5) is bonded to one Ba(4), one Ba(5), two equivalent Ba(2), one Nb(2), and one Nb(3) atom to form distorted OBa4Nb2 octahedra that share corners with two equivalent O(1)Ba4Nb2 octahedra, corners with two equivalent O(2)Ba4Nb2 octahedra, corners with two equivalent O(5)Ba4Nb2 octahedra, corners with four equivalent O(12)Ba4NbNi octahedra, edges with two equivalent O(6)Ba4NbNi octahedra, faces with two equivalent O(1)Ba4Nb2 octahedra, faces with two equivalent O(2)Ba4Nb2 octahedra, and faces with two equivalent O(12)Ba4NbNi octahedra. The corner-sharing octahedral tilt angles range from 0-60°. In the sixth O site, O(6) is bonded to one Ba(2), one Ba(3), two equivalent Ba(5), one Nb(1), and one Ni(1) atom to form distorted OBa4NbNi octahedra that share corners with two equivalent O(2)Ba4Nb2 octahedra, corners with two equivalent O(4)Ba4Nb2 octahedra, corners with two equivalent O(13)Ba4NbNi octahedra, corners with two equivalent O(6)Ba4NbNi octahedra, corners with four equivalent O(1)Ba4Nb2 octahedra, corners with four equivalent O(12)Ba4NbNi octahedra, edges with two equivalent O(5)Ba4Nb2 octahedra, faces with two equivalent O(1)Ba4Nb2 octahedra, and faces with two equivalent O(12)Ba4NbNi octahedra. The corner-sharing octahedral tilt angles range from 1-62°. In the seventh O site, O(7) is bonded in a distorted linear geometry to one Ba(2), three equivalent Ba(4), one Nb(2), and one Ni(1) atom. In the eighth O site, O(8) is bonded in a distorted linear geometry to one Ba(1), one Ba(5), two equivalent Ba(3), one Nb(3), and one Ni(2) atom. In the ninth O site, O(9) is bonded to one Ba(1), three equivalent Ba(6), one Nb(4), and one Ni(2) atom to form distorted OBa4NbNi octahedra that share corners with two equivalent O(1)Ba4Nb2 octahedra, corners with two equivalent O(4)Ba4Nb2 octahedra, corners with two equivalent O(9)Ba4NbNi octahedra, corners with four equivalent O(3)Ba4Nb2 octahedra, corners with six equivalent O(13)Ba4NbNi octahedra, edges with two equivalent O(4)Ba4Nb2 octahedra, edges with two equivalent O(9)Ba4NbNi octahedra, faces with two equivalent O(3)Ba4Nb2 octahedra, and faces with four equivalent O(13)Ba4NbNi octahedra. The corner-sharing octahedral tilt angles range from 1-62°. In the tenth O site, O(10) is bonded in a distorted linear geometry to one Ba(1), one Ba(3), one Ba(5), one Ba(6), one Nb(1), and one Ni(2) atom. In the eleventh O site, O(11) is bonded in a distorted linear geometry to one Ba(2), one Ba(5), two equivalent Ba(4), one Nb(2), and one Ni(1) atom. In the twelfth O site, O(12) is bonded to one Ba(2), one Ba(3), one Ba(4), one Ba(5), one Nb(3), and one Ni(1) atom to form distorted OBa4NbNi octahedra that share  a cornercorner with one O(4)Ba4Nb2 octahedra, corners with two equivalent O(2)Ba4Nb2 octahedra, corners with two equivalent O(5)Ba4Nb2 octahedra, corners with two equivalent O(13)Ba4NbNi octahedra, corners with two equivalent O(6)Ba4NbNi octahedra, corners with three equivalent O(1)Ba4Nb2 octahedra,  an edgeedge with one O(1)Ba4Nb2 octahedra,  an edgeedge with one O(2)Ba4Nb2 octahedra,  a faceface with one O(1)Ba4Nb2 octahedra,  a faceface with one O(5)Ba4Nb2 octahedra,  a faceface with one O(6)Ba4NbNi octahedra, and faces with two equivalent O(12)Ba4NbNi octahedra. The corner-sharing octahedral tilt angles range from 1-62°. In the thirteenth O site, O(13) is bonded to one Ba(1), one Ba(3), two equivalent Ba(6), one Nb(4), and one Ni(2) atom to form distorted OBa4NbNi octahedra that share  a cornercorner with one O(6)Ba4NbNi octahedra, corners with two equivalent O(1)Ba4Nb2 octahedra, corners with two equivalent O(12)Ba4NbNi octahedra, corners with two equivalent O(13)Ba4NbNi octahedra, corners with three equivalent O(3)Ba4Nb2 octahedra, corners with three equivalent O(4)Ba4Nb2 octahedra, corners with three equivalent O(9)Ba4NbNi octahedra,  an edgeedge with one O(1)Ba4Nb2 octahedra,  an edgeedge with one O(3)Ba4Nb2 octahedra,  an edgeedge with one O(13)Ba4NbNi octahedra,  a faceface with one O(3)Ba4Nb2 octahedra,  a faceface with one O(4)Ba4Nb2 octahedra, faces with two equivalent O(13)Ba4NbNi octahedra, and faces with two equivalent O(9)Ba4NbNi octahedra. The corner-sharing octahedral tilt angles range from 1-62°.
Ba3NiNb2O9 is (Cubic) Perovskite-derived structured and crystallizes in the monoclinic P2_1/m space group. There are six inequivalent Ba sites. In the first Ba site, Ba(1) is bonded to one O(8), one O(9), two equivalent O(1), two equivalent O(10), two equivalent O(13), two equivalent O(3), and two equivalent O(4) atoms to form BaO12 cuboctahedra that share  a cornercorner with one Ba(5)O12 cuboctahedra, corners with two equivalent Ba(2)O12 cuboctahedra, corners with two equivalent Ba(3)O12 cuboctahedra, corners with three equivalent Ba(6)O12 cuboctahedra, corners with four equivalent Ba(1)O12 cuboctahedra,  a faceface with one Ba(5)O12 cuboctahedra, faces with two equivalent Ba(3)O12 cuboctahedra, faces with three equivalent Ba(6)O12 cuboctahedra,  a faceface with one Nb(3)O6 octahedra, faces with two equivalent Nb(1)O6 octahedra, faces with two equivalent Ni(2)O6 octahedra, and faces with three equivalent Nb(4)O6 octahedra. The Ba(1)-O(8) bond length is 2.91 Å. The Ba(1)-O(9) bond length is 2.91 Å. Both Ba(1)-O(1) bond lengths are 2.92 Å. Both Ba(1)-O(10) bond lengths are 2.91 Å. Both Ba(1)-O(13) bond lengths are 2.91 Å. Both Ba(1)-O(3) bond lengths are 2.92 Å. Both Ba(1)-O(4) bond lengths are 2.92 Å. In the second Ba site, Ba(2) is bonded to one O(6), one O(7), two equivalent O(1), two equivalent O(11), two equivalent O(12), two equivalent O(2), and two equivalent O(5) atoms to form BaO12 cuboctahedra that share  a cornercorner with one Ba(3)O12 cuboctahedra, corners with two equivalent Ba(1)O12 cuboctahedra, corners with two equivalent Ba(5)O12 cuboctahedra, corners with three equivalent Ba(4)O12 cuboctahedra, corners with four equivalent Ba(2)O12 cuboctahedra,  a faceface with one Ba(3)O12 cuboctahedra, faces with two equivalent Ba(5)O12 cuboctahedra, faces with three equivalent Ba(4)O12 cuboctahedra,  a faceface with one Nb(1)O6 octahedra, faces with two equivalent Nb(3)O6 octahedra, faces with two equivalent Ni(1)O6 octahedra, and faces with three equivalent Nb(2)O6 octahedra. The Ba(2)-O(6) bond length is 2.91 Å. The Ba(2)-O(7) bond length is 2.91 Å. Both Ba(2)-O(1) bond lengths are 2.92 Å. Both Ba(2)-O(11) bond lengths are 2.91 Å. Both Ba(2)-O(12) bond lengths are 2.91 Å. Both Ba(2)-O(2) bond lengths are 2.92 Å. Both Ba(2)-O(5) bond lengths are 2.92 Å. In the third Ba site, Ba(3) is bonded to one O(4), one O(6), two equivalent O(1), two equivalent O(10), two equivalent O(12), two equivalent O(13), and two equivalent O(8) atoms to form BaO12 cuboctahedra that share  a cornercorner with one Ba(2)O12 cuboctahedra, corners with two equivalent Ba(1)O12 cuboctahedra, corners with two equivalent Ba(3)O12 cuboctahedra, corners with two equivalent Ba(4)O12 cuboctahedra, corners with two equivalent Ba(5)O12 cuboctahedra, corners with three equivalent Ba(6)O12 cuboctahedra,  a faceface with one Ba(2)O12 cuboctahedra,  a faceface with one Ba(6)O12 cuboctahedra, faces with two equivalent Ba(1)O12 cuboctahedra, faces with two equivalent Ba(5)O12 cuboctahedra,  a faceface with one Nb(4)O6 octahedra,  a faceface with one Ni(1)O6 octahedra, faces with two equivalent Nb(1)O6 octahedra, faces with two equivalent Nb(3)O6 octahedra, and faces with two equivalent Ni(2)O6 octahedra. The Ba(3)-O(4) bond length is 2.94 Å. The Ba(3)-O(6) bond length is 2.94 Å. Both Ba(3)-O(1) bond lengths are 2.94 Å. Both Ba(3)-O(10) bond lengths are 2.94 Å. Both Ba(3)-O(12) bond lengths are 2.92 Å. Both Ba(3)-O(13) bond lengths are 2.92 Å. Both Ba(3)-O(8) bond lengths are 2.92 Å. In the fourth Ba site, Ba(4) is bonded to one O(5), two equivalent O(12), two equivalent O(2), three equivalent O(7), and four equivalent O(11) atoms to form BaO12 cuboctahedra that share corners with two equivalent Ba(3)O12 cuboctahedra, corners with three equivalent Ba(2)O12 cuboctahedra, corners with three equivalent Ba(5)O12 cuboctahedra, corners with four equivalent Ba(4)O12 cuboctahedra,  a faceface with one Ba(5)O12 cuboctahedra, faces with two equivalent Ba(4)O12 cuboctahedra, faces with three equivalent Ba(2)O12 cuboctahedra,  a faceface with one Nb(3)O6 octahedra, faces with three equivalent Ni(1)O6 octahedra, and faces with four equivalent Nb(2)O6 octahedra. The Ba(4)-O(5) bond length is 2.94 Å. Both Ba(4)-O(12) bond lengths are 2.92 Å. Both Ba(4)-O(2) bond lengths are 2.94 Å. There are two shorter (2.92 Å) and one longer (2.94 Å) Ba(4)-O(7) bond length. There are two shorter (2.92 Å) and two longer (2.94 Å) Ba(4)-O(11) bond lengths. In the fifth Ba site, Ba(5) is bonded to one O(5), one O(8), two equivalent O(1), two equivalent O(10), two equivalent O(11), two equivalent O(12), and two equivalent O(6) atoms to form BaO12 cuboctahedra that share  a cornercorner with one Ba(1)O12 cuboctahedra, corners with two equivalent Ba(2)O12 cuboctahedra, corners with two equivalent Ba(3)O12 cuboctahedra, corners with two equivalent Ba(5)O12 cuboctahedra, corners with two equivalent Ba(6)O12 cuboctahedra, corners with three equivalent Ba(4)O12 cuboctahedra,  a faceface with one Ba(1)O12 cuboctahedra,  a faceface with one Ba(4)O12 cuboctahedra, faces with two equivalent Ba(2)O12 cuboctahedra, faces with two equivalent Ba(3)O12 cuboctahedra,  a faceface with one Nb(2)O6 octahedra,  a faceface with one Ni(2)O6 octahedra, faces with two equivalent Nb(1)O6 octahedra, faces with two equivalent Nb(3)O6 octahedra, and faces with two equivalent Ni(1)O6 octahedra. The Ba(5)-O(5) bond length is 2.94 Å. The Ba(5)-O(8) bond length is 2.94 Å. Both Ba(5)-O(1) bond lengths are 2.94 Å. Both Ba(5)-O(10) bond lengths are 2.92 Å. Both Ba(5)-O(11) bond lengths are 2.92 Å. Both Ba(5)-O(12) bond lengths are 2.94 Å. Both Ba(5)-O(6) bond lengths are 2.92 Å. In the sixth Ba site, Ba(6) is bonded to one O(4), two equivalent O(10), two equivalent O(3), three equivalent O(9), and four equivalent O(13) atoms to form BaO12 cuboctahedra that share corners with two equivalent Ba(5)O12 cuboctahedra, corners with three equivalent Ba(1)O12 cuboctahedra, corners with three equivalent Ba(3)O12 cuboctahedra, corners with four equivalent Ba(6)O12 cuboctahedra,  a faceface with one Ba(3)O12 cuboctahedra, faces with two equivalent Ba(6)O12 cuboctahedra, faces with three equivalent Ba(1)O12 cuboctahedra,  a faceface with one Nb(1)O6 octahedra, faces with three equivalent Ni(2)O6 octahedra, and faces with four equivalent Nb(4)O6 octahedra. The Ba(6)-O(4) bond length is 2.94 Å. Both Ba(6)-O(10) bond lengths are 2.92 Å. Both Ba(6)-O(3) bond lengths are 2.94 Å. There are two shorter (2.92 Å) and one longer (2.94 Å) Ba(6)-O(9) bond length. There are two shorter (2.92 Å) and two longer (2.94 Å) Ba(6)-O(13) bond lengths. There are four inequivalent Nb sites. In the first Nb site, Nb(1) is bonded to one O(4), one O(6), two equivalent O(1), and two equivalent O(10) atoms to form NbO6 octahedra that share  a cornercorner with one Nb(4)O6 octahedra,  a cornercorner with one Ni(1)O6 octahedra, corners with two equivalent Nb(3)O6 octahedra, corners with two equivalent Ni(2)O6 octahedra,  a faceface with one Ba(2)O12 cuboctahedra,  a faceface with one Ba(6)O12 cuboctahedra, faces with two equivalent Ba(1)O12 cuboctahedra, faces with two equivalent Ba(3)O12 cuboctahedra, and faces with two equivalent Ba(5)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 0-3°. The Nb(1)-O(4) bond length is 2.12 Å. The Nb(1)-O(6) bond length is 1.96 Å. Both Nb(1)-O(1) bond lengths are 2.12 Å. Both Nb(1)-O(10) bond lengths are 1.96 Å. In the second Nb site, Nb(2) is bonded to one O(5), one O(7), two equivalent O(11), and two equivalent O(2) atoms to form NbO6 octahedra that share  a cornercorner with one Nb(3)O6 octahedra, corners with two equivalent Nb(2)O6 octahedra, corners with three equivalent Ni(1)O6 octahedra,  a faceface with one Ba(5)O12 cuboctahedra, faces with three equivalent Ba(2)O12 cuboctahedra, and faces with four equivalent Ba(4)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 0-3°. The Nb(2)-O(5) bond length is 2.12 Å. The Nb(2)-O(7) bond length is 1.96 Å. Both Nb(2)-O(11) bond lengths are 1.96 Å. Both Nb(2)-O(2) bond lengths are 2.12 Å. In the third Nb site, Nb(3) is bonded to one O(5), one O(8), two equivalent O(1), and two equivalent O(12) atoms to form NbO6 octahedra that share  a cornercorner with one Nb(2)O6 octahedra,  a cornercorner with one Ni(2)O6 octahedra, corners with two equivalent Nb(1)O6 octahedra, corners with two equivalent Ni(1)O6 octahedra,  a faceface with one Ba(1)O12 cuboctahedra,  a faceface with one Ba(4)O12 cuboctahedra, faces with two equivalent Ba(2)O12 cuboctahedra, faces with two equivalent Ba(3)O12 cuboctahedra, and faces with two equivalent Ba(5)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 0-3°. The Nb(3)-O(5) bond length is 2.12 Å. The Nb(3)-O(8) bond length is 1.96 Å. Both Nb(3)-O(1) bond lengths are 2.12 Å. Both Nb(3)-O(12) bond lengths are 1.96 Å. In the fourth Nb site, Nb(4) is bonded to one O(4), one O(9), two equivalent O(13), and two equivalent O(3) atoms to form NbO6 octahedra that share  a cornercorner with one Nb(1)O6 octahedra, corners with two equivalent Nb(4)O6 octahedra, corners with three equivalent Ni(2)O6 octahedra,  a faceface with one Ba(3)O12 cuboctahedra, faces with three equivalent Ba(1)O12 cuboctahedra, and faces with four equivalent Ba(6)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 0-3°. The Nb(4)-O(4) bond length is 2.12 Å. The Nb(4)-O(9) bond length is 1.96 Å. Both Nb(4)-O(13) bond lengths are 1.96 Å. Both Nb(4)-O(3) bond lengths are 2.12 Å. There are two inequivalent Ni sites. In the first Ni site, Ni(1) is bonded to one O(6), one O(7), two equivalent O(11), and two equivalent O(12) atoms to form NiO6 octahedra that share  a cornercorner with one Nb(1)O6 octahedra, corners with two equivalent Nb(3)O6 octahedra, corners with three equivalent Nb(2)O6 octahedra,  a faceface with one Ba(3)O12 cuboctahedra, faces with two equivalent Ba(2)O12 cuboctahedra, faces with two equivalent Ba(5)O12 cuboctahedra, and faces with three equivalent Ba(4)O12 cuboctahedra. The corner-sharing octahedral tilt angles are 3°. The Ni(1)-O(6) bond length is 2.14 Å. The Ni(1)-O(7) bond length is 2.13 Å. Both Ni(1)-O(11) bond lengths are 2.13 Å. Both Ni(1)-O(12) bond lengths are 2.14 Å. In the second Ni site, Ni(2) is bonded to one O(8), one O(9), two equivalent O(10), and two equivalent O(13) atoms to form NiO6 octahedra that share  a cornercorner with one Nb(3)O6 octahedra, corners with two equivalent Nb(1)O6 octahedra, corners with three equivalent Nb(4)O6 octahedra,  a faceface with one Ba(5)O12 cuboctahedra, faces with two equivalent Ba(1)O12 cuboctahedra, faces with two equivalent Ba(3)O12 cuboctahedra, and faces with three equivalent Ba(6)O12 cuboctahedra. The corner-sharing octahedral tilt angles are 3°. The Ni(2)-O(8) bond length is 2.13 Å. The Ni(2)-O(9) bond length is 2.14 Å. Both Ni(2)-O(10) bond lengths are 2.13 Å. Both Ni(2)-O(13) bond lengths are 2.14 Å. There are thirteen inequivalent O sites. In the first O site, O(1) is bonded to one Ba(1), one Ba(2), one Ba(3), one Ba(5), one Nb(1), and one Nb(3) atom to form distorted OBa4Nb2 octahedra that share  a cornercorner with one O(4)Ba4Nb2 octahedra,  a cornercorner with one O(5)Ba4Nb2 octahedra,  a cornercorner with one O(9)Ba4NbNi octahedra, corners with two equivalent O(2)Ba4Nb2 octahedra, corners with two equivalent O(3)Ba4Nb2 octahedra, corners with two equivalent O(13)Ba4NbNi octahedra, corners with two equivalent O(6)Ba4NbNi octahedra, corners with three equivalent O(12)Ba4NbNi octahedra,  an edgeedge with one O(12)Ba4NbNi octahedra,  an edgeedge with one O(13)Ba4NbNi octahedra,  a faceface with one O(4)Ba4Nb2 octahedra,  a faceface with one O(5)Ba4Nb2 octahedra,  a faceface with one O(12)Ba4NbNi octahedra,  a faceface with one O(6)Ba4NbNi octahedra, and faces with two equivalent O(1)Ba4Nb2 octahedra. The corner-sharing octahedral tilt angles range from 0-62°. In the second O site, O(2) is bonded to two equivalent Ba(2), two equivalent Ba(4), and two equivalent Nb(2) atoms to form distorted OBa4Nb2 octahedra that share corners with two equivalent O(5)Ba4Nb2 octahedra, corners with two equivalent O(6)Ba4NbNi octahedra, corners with four equivalent O(1)Ba4Nb2 octahedra, corners with four equivalent O(12)Ba4NbNi octahedra, edges with two equivalent O(12)Ba4NbNi octahedra, faces with two equivalent O(2)Ba4Nb2 octahedra, and faces with two equivalent O(5)Ba4Nb2 octahedra. The corner-sharing octahedral tilt angles range from 0-62°. In the third O site, O(3) is bonded to two equivalent Ba(1), two equivalent Ba(6), and two equivalent Nb(4) atoms to form distorted OBa4Nb2 octahedra that share corners with two equivalent O(4)Ba4Nb2 octahedra, corners with four equivalent O(1)Ba4Nb2 octahedra, corners with four equivalent O(9)Ba4NbNi octahedra, corners with six equivalent O(13)Ba4NbNi octahedra, edges with two equivalent O(13)Ba4NbNi octahedra, faces with two equivalent O(3)Ba4Nb2 octahedra, faces with two equivalent O(4)Ba4Nb2 octahedra, faces with two equivalent O(13)Ba4NbNi octahedra, and faces with two equivalent O(9)Ba4NbNi octahedra. The corner-sharing octahedral tilt angles range from 0-62°. In the fourth O site, O(4) is bonded to one Ba(3), one Ba(6), two equivalent Ba(1), one Nb(1), and one Nb(4) atom to form distorted OBa4Nb2 octahedra that share corners with two equivalent O(1)Ba4Nb2 octahedra, corners with two equivalent O(3)Ba4Nb2 octahedra, corners with two equivalent O(4)Ba4Nb2 octahedra, corners with two equivalent O(12)Ba4NbNi octahedra, corners with two equivalent O(6)Ba4NbNi octahedra, corners with two equivalent O(9)Ba4NbNi octahedra, corners with six equivalent O(13)Ba4NbNi octahedra, edges with two equivalent O(9)Ba4NbNi octahedra, faces with two equivalent O(1)Ba4Nb2 octahedra, faces with two equivalent O(3)Ba4Nb2 octahedra, and faces with two equivalent O(13)Ba4NbNi octahedra. The corner-sharing octahedral tilt angles range from 0-62°. In the fifth O site, O(5) is bonded to one Ba(4), one Ba(5), two equivalent Ba(2), one Nb(2), and one Nb(3) atom to form distorted OBa4Nb2 octahedra that share corners with two equivalent O(1)Ba4Nb2 octahedra, corners with two equivalent O(2)Ba4Nb2 octahedra, corners with two equivalent O(5)Ba4Nb2 octahedra, corners with four equivalent O(12)Ba4NbNi octahedra, edges with two equivalent O(6)Ba4NbNi octahedra, faces with two equivalent O(1)Ba4Nb2 octahedra, faces with two equivalent O(2)Ba4Nb2 octahedra, and faces with two equivalent O(12)Ba4NbNi octahedra. The corner-sharing octahedral tilt angles range from 0-60°. In the sixth O site, O(6) is bonded to one Ba(2), one Ba(3), two equivalent Ba(5), one Nb(1), and one Ni(1) atom to form distorted OBa4NbNi octahedra that share corners with two equivalent O(2)Ba4Nb2 octahedra, corners with two equivalent O(4)Ba4Nb2 octahedra, corners with two equivalent O(13)Ba4NbNi octahedra, corners with two equivalent O(6)Ba4NbNi octahedra, corners with four equivalent O(1)Ba4Nb2 octahedra, corners with four equivalent O(12)Ba4NbNi octahedra, edges with two equivalent O(5)Ba4Nb2 octahedra, faces with two equivalent O(1)Ba4Nb2 octahedra, and faces with two equivalent O(12)Ba4NbNi octahedra. The corner-sharing octahedral tilt angles range from 1-62°. In the seventh O site, O(7) is bonded in a distorted linear geometry to one Ba(2), three equivalent Ba(4), one Nb(2), and one Ni(1) atom. In the eighth O site, O(8) is bonded in a distorted linear geometry to one Ba(1), one Ba(5), two equivalent Ba(3), one Nb(3), and one Ni(2) atom. In the ninth O site, O(9) is bonded to one Ba(1), three equivalent Ba(6), one Nb(4), and one Ni(2) atom to form distorted OBa4NbNi octahedra that share corners with two equivalent O(1)Ba4Nb2 octahedra, corners with two equivalent O(4)Ba4Nb2 octahedra, corners with two equivalent O(9)Ba4NbNi octahedra, corners with four equivalent O(3)Ba4Nb2 octahedra, corners with six equivalent O(13)Ba4NbNi octahedra, edges with two equivalent O(4)Ba4Nb2 octahedra, edges with two equivalent O(9)Ba4NbNi octahedra, faces with two equivalent O(3)Ba4Nb2 octahedra, and faces with four equivalent O(13)Ba4NbNi octahedra. The corner-sharing octahedral tilt angles range from 1-62°. In the tenth O site, O(10) is bonded in a distorted linear geometry to one Ba(1), one Ba(3), one Ba(5), one Ba(6), one Nb(1), and one Ni(2) atom. In the eleventh O site, O(11) is bonded in a distorted linear geometry to one Ba(2), one Ba(5), two equivalent Ba(4), one Nb(2), and one Ni(1) atom. In the twelfth O site, O(12) is bonded to one Ba(2), one Ba(3), one Ba(4), one Ba(5), one Nb(3), and one Ni(1) atom to form distorted OBa4NbNi octahedra that share  a cornercorner with one O(4)Ba4Nb2 octahedra, corners with two equivalent O(2)Ba4Nb2 octahedra, corners with two equivalent O(5)Ba4Nb2 octahedra, corners with two equivalent O(13)Ba4NbNi octahedra, corners with two equivalent O(6)Ba4NbNi octahedra, corners with three equivalent O(1)Ba4Nb2 octahedra,  an edgeedge with one O(1)Ba4Nb2 octahedra,  an edgeedge with one O(2)Ba4Nb2 octahedra,  a faceface with one O(1)Ba4Nb2 octahedra,  a faceface with one O(5)Ba4Nb2 octahedra,  a faceface with one O(6)Ba4NbNi octahedra, and faces with two equivalent O(12)Ba4NbNi octahedra. The corner-sharing octahedral tilt angles range from 1-62°. In the thirteenth O site, O(13) is bonded to one Ba(1), one Ba(3), two equivalent Ba(6), one Nb(4), and one Ni(2) atom to form distorted OBa4NbNi octahedra that share  a cornercorner with one O(6)Ba4NbNi octahedra, corners with two equivalent O(1)Ba4Nb2 octahedra, corners with two equivalent O(12)Ba4NbNi octahedra, corners with two equivalent O(13)Ba4NbNi octahedra, corners with three equivalent O(3)Ba4Nb2 octahedra, corners with three equivalent O(4)Ba4Nb2 octahedra, corners with three equivalent O(9)Ba4NbNi octahedra,  an edgeedge with one O(1)Ba4Nb2 octahedra,  an edgeedge with one O(3)Ba4Nb2 octahedra,  an edgeedge with one O(13)Ba4NbNi octahedra,  a faceface with one O(3)Ba4Nb2 octahedra,  a faceface with one O(4)Ba4Nb2 octahedra, faces with two equivalent O(13)Ba4NbNi octahedra, and faces with two equivalent O(9)Ba4NbNi octahedra. The corner-sharing octahedral tilt angles range from 1-62°.