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UN2 is Fluorite structured and crystallizes in the cubic Fm-3m space group. The structure is three-dimensional. U6+ is bonded in a body-centered cubic geometry to eight equivalent N3- atoms. All U–N bond lengths are 2.29 Å. N3- is bonded to four equivalent U6+ atoms to form a mixture of edge and corner-sharing NU4 tetrahedra.
UN1 is Halite, Rock Salt structured and crystallizes in the trigonal R-3m space group. The structure is three-dimensional. U3+ is bonded to six equivalent N3- atoms to form a mixture of edge and corner-sharing UN6 octahedra. The corner-sharing octahedral tilt angles are 0°. All U–N bond lengths are 2.44 Å. N3- is bonded to six equivalent U3+ atoms to form a mixture of edge and corner-sharing NU6 octahedra. The corner-sharing octahedral tilt angles are 0°.
U2N3 crystallizes in the cubic Ia-3 space group. The structure is three-dimensional. there are two inequivalent U+4.50+ sites. In the first U+4.50+ site, U+4.50+ is bonded to six equivalent N3- atoms to form a mixture of distorted edge and corner-sharing UN6 octahedra. The corner-sharing octahedral tilt angles are 59°. All U–N bond lengths are 2.27 Å. In the second U+4.50+ site, U+4.50+ is bonded to six equivalent N3- atoms to form a mixture of distorted edge and corner-sharing UN6 octahedra. The corner-sharing octahedra tilt angles range from 59–61°. There are a spread of U–N bond distances ranging from 2.25–2.33 Å. N3- is bonded to four U+4.50+ atoms to form a mixture of edge and corner-sharing NU4 tetrahedra.
U2N3 crystallizes in the trigonal P-3m1 space group. The structure is three-dimensional. U+4.50+ is bonded in a 7-coordinate geometry to seven N3- atoms. There are a spread of U–N bond distances ranging from 2.23–2.55 Å. There are two inequivalent N3- sites. In the first N3- site, N3- is bonded to six equivalent U+4.50+ atoms to form NU6 octahedra that share corners with twelve equivalent NU4 tetrahedra, edges with six equivalent NU6 octahedra, and edges with six equivalent NU4 tetrahedra. In the second N3- site, N3- is bonded to four equivalent U+4.50+ atoms to form NU4 tetrahedra that share corners with six equivalent NU6 octahedra, corners with six equivalent NU4 tetrahedra, edges with three equivalent NU6 octahedra, and edges with three equivalent NU4 tetrahedra. The corner-sharing octahedra tilt angles range from 16–57°.