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SrN2 crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. Sr2+ is bonded in a distorted q4 geometry to ten equivalent N1- atoms. There are two shorter (2.52 Å) and eight longer (2.80 Å) Sr–N bond lengths. N1- is bonded in a 2-coordinate geometry to five equivalent Sr2+ and one N1- atom. The N–N bond length is 1.25 Å.
Sr2N is trigonal omega-like structured and crystallizes in the trigonal R-3m space group. The structure is two-dimensional and consists of three Sr2N sheets oriented in the (0, 0, 1) direction. Sr is bonded in a distorted T-shaped geometry to three equivalent N atoms. All Sr–N bond lengths are 2.62 Å. N is bonded to six equivalent Sr atoms to form edge-sharing NSr6 octahedra.
SrN6 crystallizes in the orthorhombic Fddd space group. The structure is three-dimensional. Sr2+ is bonded in a 8-coordinate geometry to eight equivalent N+0.33- atoms. There are four shorter (2.72 Å) and four longer (2.75 Å) Sr–N bond lengths. There are two inequivalent N+0.33- sites. In the first N+0.33- site, N+0.33- is bonded in a trigonal planar geometry to two equivalent Sr2+ and one N+0.33- atom. The N–N bond length is 1.18 Å. In the second N+0.33- site, N+0.33- is bonded in a linear geometry to two equivalent N+0.33- atoms.
SrN crystallizes in the monoclinic C2/m space group. The structure is three-dimensional. there are two inequivalent Sr2+ sites. In the first Sr2+ site, Sr2+ is bonded to seven N2- atoms to form a mixture of distorted edge and face-sharing SrN7 pentagonal bipyramids. There are a spread of Sr–N bond distances ranging from 2.62–3.00 Å. In the second Sr2+ site, Sr2+ is bonded in a rectangular see-saw-like geometry to four N2- atoms. There are a spread of Sr–N bond distances ranging from 2.57–2.65 Å. There are two inequivalent N2- sites. In the first N2- site, N2- is bonded in a 6-coordinate geometry to five Sr2+ and one N2- atom. The N–N bond length is 1.23 Å. In the second N2- site, N2- is bonded to six Sr2+ atoms to form edge-sharing NSr6 octahedra.
Sr4N3 crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are four inequivalent Sr2+ sites. In the first Sr2+ site, Sr2+ is bonded in a rectangular see-saw-like geometry to four N+2.67- atoms. There are a spread of Sr–N bond distances ranging from 2.53–2.80 Å. In the second Sr2+ site, Sr2+ is bonded to four N+2.67- atoms to form distorted SrN4 trigonal pyramids that share corners with two equivalent SrN5 square pyramids, corners with six SrN4 trigonal pyramids, edges with two equivalent SrN5 square pyramids, and an edgeedge with one SrN4 trigonal pyramid. There are a spread of Sr–N bond distances ranging from 2.38–2.71 Å. In the third Sr2+ site, Sr2+ is bonded to four N+2.67- atoms to form SrN4 trigonal pyramids that share corners with two equivalent SrN5 square pyramids, corners with six SrN4 trigonal pyramids, edges with two equivalent SrN5 square pyramids, and an edgeedge with one SrN4 trigonal pyramid. There are a spread of Sr–N bond distances ranging from 2.56–2.85 Å. In the fourth Sr2+ site, Sr2+ is bonded to five N+2.67- atoms to form distorted SrN5 square pyramids that share corners with four SrN4 trigonal pyramids, edges with two equivalent SrN5 square pyramids, and edges with four SrN4 trigonal pyramids. There are a spread of Sr–N bond distances ranging from 2.53–2.85 Å. There are three inequivalent N+2.67- sites. In the first N+2.67- site, N+2.67- is bonded to six Sr2+ atoms to form edge-sharing NSr6 octahedra. In the second N+2.67- site, N+2.67- is bonded in a 5-coordinate geometry to five Sr2+ atoms. In the third N+2.67- site, N+2.67- is bonded to six Sr2+ atoms to form distorted edge-sharing NSr6 octahedra.
Sr3N2 is Corundum-like structured and crystallizes in the cubic Ia-3 space group. The structure is three-dimensional. Sr2+ is bonded to four N3- atoms to form a mixture of corner and edge-sharing SrN4 trigonal pyramids. There are a spread of Sr–N bond distances ranging from 2.63–2.68 Å. There are two inequivalent N3- sites. In the first N3- site, N3- is bonded to six equivalent Sr2+ atoms to form a mixture of distorted corner and edge-sharing NSr6 octahedra. The corner-sharing octahedra tilt angles range from 52–53°. In the second N3- site, N3- is bonded to six equivalent Sr2+ atoms to form a mixture of corner and edge-sharing NSr6 octahedra. The corner-sharing octahedral tilt angles are 53°.
Sr3N2 is High-temperature superconductor-like structured and crystallizes in the cubic Pm-3m space group. The structure is three-dimensional and consists of one ammonia molecule and one Sr3N framework. In the Sr3N framework, Sr2+ is bonded in a linear geometry to two equivalent N3- atoms. Both Sr–N bond lengths are 2.49 Å. N3- is bonded to six equivalent Sr2+ atoms to form corner-sharing NSr6 octahedra. The corner-sharing octahedral tilt angles are 0°.