SrNb4O6 crystallizes in the tetragonal P4/mmm space group. Sr(1) is bonded to four equivalent O(1), four equivalent O(2), and four equivalent O(5) atoms to form SrO12 cuboctahedra that share corners with eight equivalent Sr(1)O12 cuboctahedra, faces with five equivalent Sr(1)O12 cuboctahedra, faces with four equivalent Nb(2)O6 octahedra, and faces with four equivalent Nb(3)O5 square pyramids. There are four inequivalent Nb sites. In the first Nb site, Nb(1) is bonded in a square co-planar geometry to one O(1), one O(4), and two equivalent O(3) atoms. In the second Nb site, Nb(2) is bonded to two equivalent O(2) and four equivalent O(5) atoms to form NbO6 octahedra that share corners with four equivalent Nb(2)O6 octahedra, corners with two equivalent Nb(3)O5 square pyramids, and faces with eight equivalent Sr(1)O12 cuboctahedra. The corner-sharing octahedra are not tilted. In the third Nb site, Nb(3) is bonded to one O(2) and four equivalent O(1) atoms to form NbO5 square pyramids that share  a cornercorner with one Nb(2)O6 octahedra, corners with four equivalent Nb(3)O5 square pyramids, and faces with four equivalent Sr(1)O12 cuboctahedra. The corner-sharing octahedra are not tilted. In the fourth Nb site, Nb(4) is bonded in a square co-planar geometry to four equivalent O(4) atoms. There are five inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Sr(1), one Nb(1), and two equivalent Nb(3) atoms to form distorted OSr2Nb3 trigonal bipyramids that share corners with six equivalent O(5)Sr4Nb2 octahedra, corners with four equivalent O(1)Sr2Nb3 trigonal bipyramids,  an edgeedge with one O(5)Sr4Nb2 octahedra, and edges with four equivalent O(1)Sr2Nb3 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 3-63°. In the second O site, O(2) is bonded in a distorted linear geometry to four equivalent Sr(1), one Nb(2), and one Nb(3) atom. In the third O site, O(3) is bonded in a rectangular see-saw-like geometry to four equivalent Nb(1) atoms. In the fourth O site, O(4) is bonded in a square co-planar geometry to two equivalent Nb(1) and two equivalent Nb(4) atoms. In the fifth O site, O(5) is bonded to four equivalent Sr(1) and two equivalent Nb(2) atoms to form distorted OSr4Nb2 octahedra that share corners with two equivalent O(5)Sr4Nb2 octahedra, corners with twelve equivalent O(1)Sr2Nb3 trigonal bipyramids, edges with two equivalent O(5)Sr4Nb2 octahedra, edges with two equivalent O(1)Sr2Nb3 trigonal bipyramids, and faces with four equivalent O(5)Sr4Nb2 octahedra. The corner-sharing octahedra are not tilted.
SrNb4O6 crystallizes in the tetragonal P4/mmm space group. Sr(1) is bonded to four equivalent O(1), four equivalent O(2), and four equivalent O(5) atoms to form SrO12 cuboctahedra that share corners with eight equivalent Sr(1)O12 cuboctahedra, faces with five equivalent Sr(1)O12 cuboctahedra, faces with four equivalent Nb(2)O6 octahedra, and faces with four equivalent Nb(3)O5 square pyramids. All Sr(1)-O(1) bond lengths are 2.81 Å. All Sr(1)-O(2) bond lengths are 2.98 Å. All Sr(1)-O(5) bond lengths are 2.94 Å. There are four inequivalent Nb sites. In the first Nb site, Nb(1) is bonded in a square co-planar geometry to one O(1), one O(4), and two equivalent O(3) atoms. The Nb(1)-O(1) bond length is 2.14 Å. The Nb(1)-O(4) bond length is 2.16 Å. Both Nb(1)-O(3) bond lengths are 2.11 Å. In the second Nb site, Nb(2) is bonded to two equivalent O(2) and four equivalent O(5) atoms to form NbO6 octahedra that share corners with four equivalent Nb(2)O6 octahedra, corners with two equivalent Nb(3)O5 square pyramids, and faces with eight equivalent Sr(1)O12 cuboctahedra. The corner-sharing octahedra are not tilted. Both Nb(2)-O(2) bond lengths are 1.96 Å. All Nb(2)-O(5) bond lengths are 2.11 Å. In the third Nb site, Nb(3) is bonded to one O(2) and four equivalent O(1) atoms to form NbO5 square pyramids that share  a cornercorner with one Nb(2)O6 octahedra, corners with four equivalent Nb(3)O5 square pyramids, and faces with four equivalent Sr(1)O12 cuboctahedra. The corner-sharing octahedra are not tilted. The Nb(3)-O(2) bond length is 2.10 Å. All Nb(3)-O(1) bond lengths are 2.11 Å. In the fourth Nb site, Nb(4) is bonded in a square co-planar geometry to four equivalent O(4) atoms. All Nb(4)-O(4) bond lengths are 2.11 Å. There are five inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Sr(1), one Nb(1), and two equivalent Nb(3) atoms to form distorted OSr2Nb3 trigonal bipyramids that share corners with six equivalent O(5)Sr4Nb2 octahedra, corners with four equivalent O(1)Sr2Nb3 trigonal bipyramids,  an edgeedge with one O(5)Sr4Nb2 octahedra, and edges with four equivalent O(1)Sr2Nb3 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 3-63°. In the second O site, O(2) is bonded in a distorted linear geometry to four equivalent Sr(1), one Nb(2), and one Nb(3) atom. In the third O site, O(3) is bonded in a rectangular see-saw-like geometry to four equivalent Nb(1) atoms. In the fourth O site, O(4) is bonded in a square co-planar geometry to two equivalent Nb(1) and two equivalent Nb(4) atoms. In the fifth O site, O(5) is bonded to four equivalent Sr(1) and two equivalent Nb(2) atoms to form distorted OSr4Nb2 octahedra that share corners with two equivalent O(5)Sr4Nb2 octahedra, corners with twelve equivalent O(1)Sr2Nb3 trigonal bipyramids, edges with two equivalent O(5)Sr4Nb2 octahedra, edges with two equivalent O(1)Sr2Nb3 trigonal bipyramids, and faces with four equivalent O(5)Sr4Nb2 octahedra. The corner-sharing octahedra are not tilted.