Sr9(MnN4)2 crystallizes in the monoclinic C2/m space group. There are five inequivalent Sr sites. In the first Sr site, Sr(1) is bonded in a linear geometry to two equivalent N(4) atoms. In the second Sr site, Sr(2) is bonded to one N(2), two equivalent N(1), and two equivalent N(4) atoms to form distorted SrN5 trigonal bipyramids that share  a cornercorner with one Sr(3)N5 trigonal bipyramid, corners with two equivalent Sr(2)N5 trigonal bipyramids, corners with two equivalent Sr(5)N4 trigonal pyramids,  an edgeedge with one Sr(2)N5 trigonal bipyramid, and edges with two equivalent Sr(3)N5 trigonal bipyramids. In the third Sr site, Sr(3) is bonded to one N(3), one N(4), and three equivalent N(2) atoms to form distorted SrN5 trigonal bipyramids that share  a cornercorner with one Sr(2)N5 trigonal bipyramid, corners with two equivalent Sr(3)N5 trigonal bipyramids, corners with three equivalent Sr(5)N4 trigonal pyramids, edges with two equivalent Sr(2)N5 trigonal bipyramids, and edges with two equivalent Sr(3)N5 trigonal bipyramids. In the fourth Sr site, Sr(4) is bonded in a rectangular see-saw-like geometry to two equivalent N(1) and two equivalent N(4) atoms. In the fifth Sr site, Sr(5) is bonded to one N(1) and three equivalent N(3) atoms to form distorted SrN4 trigonal pyramids that share corners with two equivalent Sr(2)N5 trigonal bipyramids, corners with three equivalent Sr(3)N5 trigonal bipyramids, corners with two equivalent Sr(5)N4 trigonal pyramids, and edges with two equivalent Sr(5)N4 trigonal pyramids. Mn(1) is bonded in a trigonal planar geometry to one N(1), one N(2), and one N(3) atom. There are four inequivalent N sites. In the first N site, N(1) is bonded in a 6-coordinate geometry to one Sr(5), two equivalent Sr(2), two equivalent Sr(4), and one Mn(1) atom. In the second N site, N(2) is bonded to one Sr(2), three equivalent Sr(3), and one Mn(1) atom to form distorted NSr4Mn trigonal bipyramids that share  a cornercorner with one N(4)Sr6 octahedra, corners with two equivalent N(2)Sr4Mn trigonal bipyramids, corners with two equivalent N(3)Sr4Mn trigonal bipyramids, edges with two equivalent N(4)Sr6 octahedra,  an edgeedge with one N(3)Sr4Mn trigonal bipyramid, and edges with two equivalent N(2)Sr4Mn trigonal bipyramids. The corner-sharing octahedral tilt angles are 12°. In the third N site, N(3) is bonded to one Sr(3), three equivalent Sr(5), and one Mn(1) atom to form distorted NSr4Mn trigonal bipyramids that share  a cornercorner with one N(4)Sr6 octahedra, corners with two equivalent N(2)Sr4Mn trigonal bipyramids, corners with two equivalent N(3)Sr4Mn trigonal bipyramids,  an edgeedge with one N(2)Sr4Mn trigonal bipyramid, and edges with two equivalent N(3)Sr4Mn trigonal bipyramids. The corner-sharing octahedral tilt angles are 53°. In the fourth N site, N(4) is bonded to one Sr(1), one Sr(3), two equivalent Sr(2), and two equivalent Sr(4) atoms to form NSr6 octahedra that share corners with three equivalent N(4)Sr6 octahedra,  a cornercorner with one N(2)Sr4Mn trigonal bipyramid,  a cornercorner with one N(3)Sr4Mn trigonal bipyramid,  an edgeedge with one N(4)Sr6 octahedra, and edges with two equivalent N(2)Sr4Mn trigonal bipyramids. The corner-sharing octahedral tilt angles range from 0-4°.
Sr9(MnN4)2 crystallizes in the monoclinic C2/m space group. There are five inequivalent Sr sites. In the first Sr site, Sr(1) is bonded in a linear geometry to two equivalent N(4) atoms. Both Sr(1)-N(4) bond lengths are 2.54 Å. In the second Sr site, Sr(2) is bonded to one N(2), two equivalent N(1), and two equivalent N(4) atoms to form distorted SrN5 trigonal bipyramids that share  a cornercorner with one Sr(3)N5 trigonal bipyramid, corners with two equivalent Sr(2)N5 trigonal bipyramids, corners with two equivalent Sr(5)N4 trigonal pyramids,  an edgeedge with one Sr(2)N5 trigonal bipyramid, and edges with two equivalent Sr(3)N5 trigonal bipyramids. The Sr(2)-N(2) bond length is 2.70 Å. There is one shorter (2.80 Å) and one longer (3.10 Å) Sr(2)-N(1) bond length. Both Sr(2)-N(4) bond lengths are 2.61 Å. In the third Sr site, Sr(3) is bonded to one N(3), one N(4), and three equivalent N(2) atoms to form distorted SrN5 trigonal bipyramids that share  a cornercorner with one Sr(2)N5 trigonal bipyramid, corners with two equivalent Sr(3)N5 trigonal bipyramids, corners with three equivalent Sr(5)N4 trigonal pyramids, edges with two equivalent Sr(2)N5 trigonal bipyramids, and edges with two equivalent Sr(3)N5 trigonal bipyramids. The Sr(3)-N(3) bond length is 2.88 Å. The Sr(3)-N(4) bond length is 2.69 Å. All Sr(3)-N(2) bond lengths are 2.67 Å. In the fourth Sr site, Sr(4) is bonded in a rectangular see-saw-like geometry to two equivalent N(1) and two equivalent N(4) atoms. Both Sr(4)-N(1) bond lengths are 2.66 Å. There is one shorter (2.54 Å) and one longer (2.67 Å) Sr(4)-N(4) bond length. In the fifth Sr site, Sr(5) is bonded to one N(1) and three equivalent N(3) atoms to form distorted SrN4 trigonal pyramids that share corners with two equivalent Sr(2)N5 trigonal bipyramids, corners with three equivalent Sr(3)N5 trigonal bipyramids, corners with two equivalent Sr(5)N4 trigonal pyramids, and edges with two equivalent Sr(5)N4 trigonal pyramids. The Sr(5)-N(1) bond length is 2.72 Å. There are two shorter (2.69 Å) and one longer (2.74 Å) Sr(5)-N(3) bond length. Mn(1) is bonded in a trigonal planar geometry to one N(1), one N(2), and one N(3) atom. The Mn(1)-N(1) bond length is 1.73 Å. The Mn(1)-N(2) bond length is 1.71 Å. The Mn(1)-N(3) bond length is 1.72 Å. There are four inequivalent N sites. In the first N site, N(1) is bonded in a 6-coordinate geometry to one Sr(5), two equivalent Sr(2), two equivalent Sr(4), and one Mn(1) atom. In the second N site, N(2) is bonded to one Sr(2), three equivalent Sr(3), and one Mn(1) atom to form distorted NSr4Mn trigonal bipyramids that share  a cornercorner with one N(4)Sr6 octahedra, corners with two equivalent N(2)Sr4Mn trigonal bipyramids, corners with two equivalent N(3)Sr4Mn trigonal bipyramids, edges with two equivalent N(4)Sr6 octahedra,  an edgeedge with one N(3)Sr4Mn trigonal bipyramid, and edges with two equivalent N(2)Sr4Mn trigonal bipyramids. The corner-sharing octahedral tilt angles are 12°. In the third N site, N(3) is bonded to one Sr(3), three equivalent Sr(5), and one Mn(1) atom to form distorted NSr4Mn trigonal bipyramids that share  a cornercorner with one N(4)Sr6 octahedra, corners with two equivalent N(2)Sr4Mn trigonal bipyramids, corners with two equivalent N(3)Sr4Mn trigonal bipyramids,  an edgeedge with one N(2)Sr4Mn trigonal bipyramid, and edges with two equivalent N(3)Sr4Mn trigonal bipyramids. The corner-sharing octahedral tilt angles are 53°. In the fourth N site, N(4) is bonded to one Sr(1), one Sr(3), two equivalent Sr(2), and two equivalent Sr(4) atoms to form NSr6 octahedra that share corners with three equivalent N(4)Sr6 octahedra,  a cornercorner with one N(2)Sr4Mn trigonal bipyramid,  a cornercorner with one N(3)Sr4Mn trigonal bipyramid,  an edgeedge with one N(4)Sr6 octahedra, and edges with two equivalent N(2)Sr4Mn trigonal bipyramids. The corner-sharing octahedral tilt angles range from 0-4°.