Sr3Sc3N5 is Aluminum carbonitride-like structured and crystallizes in the triclinic P-1 space group. There are three inequivalent Sr sites. In the first Sr site, Sr(1) is bonded in a 4-coordinate geometry to one N(3), one N(4), and two equivalent N(2) atoms. In the second Sr site, Sr(2) is bonded in a 6-coordinate geometry to one N(3), one N(4), two equivalent N(1), and two equivalent N(5) atoms. In the third Sr site, Sr(3) is bonded in a 5-coordinate geometry to one N(1), one N(2), one N(5), and two equivalent N(3) atoms. There are three inequivalent Sc sites. In the first Sc site, Sc(1) is bonded to one N(1), one N(5), and two equivalent N(3) atoms to form a mixture of edge and corner-sharing ScN4 tetrahedra. In the second Sc site, Sc(2) is bonded to one N(1), one N(2), and two equivalent N(4) atoms to form a mixture of edge and corner-sharing ScN4 tetrahedra. In the third Sc site, Sc(3) is bonded to one N(1), one N(2), one N(4), and one N(5) atom to form a mixture of edge and corner-sharing ScN4 tetrahedra. There are five inequivalent N sites. In the first N site, N(1) is bonded to one Sr(3), two equivalent Sr(2), one Sc(1), one Sc(2), and one Sc(3) atom to form distorted NSr3Sc3 octahedra that share corners with three equivalent N(4)Sr2Sc3 square pyramids,  an edgeedge with one N(1)Sr3Sc3 octahedra, and  an edgeedge with one N(4)Sr2Sc3 square pyramid. In the second N site, N(2) is bonded in a 5-coordinate geometry to one Sr(3), two equivalent Sr(1), one Sc(2), and one Sc(3) atom. In the third N site, N(3) is bonded in a 6-coordinate geometry to one Sr(1), one Sr(2), two equivalent Sr(3), and two equivalent Sc(1) atoms. In the fourth N site, N(4) is bonded to one Sr(1), one Sr(2), one Sc(3), and two equivalent Sc(2) atoms to form distorted NSr2Sc3 square pyramids that share corners with three equivalent N(1)Sr3Sc3 octahedra,  an edgeedge with one N(1)Sr3Sc3 octahedra, and  an edgeedge with one N(4)Sr2Sc3 square pyramid. The corner-sharing octahedral tilt angles range from 18-62°. In the fifth N site, N(5) is bonded in a 5-coordinate geometry to one Sr(3), two equivalent Sr(2), one Sc(1), and one Sc(3) atom.
Sr3Sc3N5 is Aluminum carbonitride-like structured and crystallizes in the triclinic P-1 space group. There are three inequivalent Sr sites. In the first Sr site, Sr(1) is bonded in a 4-coordinate geometry to one N(3), one N(4), and two equivalent N(2) atoms. The Sr(1)-N(3) bond length is 2.55 Å. The Sr(1)-N(4) bond length is 2.67 Å. There is one shorter (2.52 Å) and one longer (3.14 Å) Sr(1)-N(2) bond length. In the second Sr site, Sr(2) is bonded in a 6-coordinate geometry to one N(3), one N(4), two equivalent N(1), and two equivalent N(5) atoms. The Sr(2)-N(3) bond length is 2.80 Å. The Sr(2)-N(4) bond length is 2.95 Å. There is one shorter (2.86 Å) and one longer (2.94 Å) Sr(2)-N(1) bond length. There is one shorter (2.52 Å) and one longer (3.01 Å) Sr(2)-N(5) bond length. In the third Sr site, Sr(3) is bonded in a 5-coordinate geometry to one N(1), one N(2), one N(5), and two equivalent N(3) atoms. The Sr(3)-N(1) bond length is 2.83 Å. The Sr(3)-N(2) bond length is 2.58 Å. The Sr(3)-N(5) bond length is 2.93 Å. There is one shorter (2.63 Å) and one longer (2.97 Å) Sr(3)-N(3) bond length. There are three inequivalent Sc sites. In the first Sc site, Sc(1) is bonded to one N(1), one N(5), and two equivalent N(3) atoms to form a mixture of edge and corner-sharing ScN4 tetrahedra. The Sc(1)-N(1) bond length is 2.15 Å. The Sc(1)-N(5) bond length is 2.07 Å. There is one shorter (2.12 Å) and one longer (2.14 Å) Sc(1)-N(3) bond length. In the second Sc site, Sc(2) is bonded to one N(1), one N(2), and two equivalent N(4) atoms to form a mixture of edge and corner-sharing ScN4 tetrahedra. The Sc(2)-N(1) bond length is 2.14 Å. The Sc(2)-N(2) bond length is 2.12 Å. There is one shorter (2.09 Å) and one longer (2.16 Å) Sc(2)-N(4) bond length. In the third Sc site, Sc(3) is bonded to one N(1), one N(2), one N(4), and one N(5) atom to form a mixture of edge and corner-sharing ScN4 tetrahedra. The Sc(3)-N(1) bond length is 2.14 Å. The Sc(3)-N(2) bond length is 2.13 Å. The Sc(3)-N(4) bond length is 2.12 Å. The Sc(3)-N(5) bond length is 2.08 Å. There are five inequivalent N sites. In the first N site, N(1) is bonded to one Sr(3), two equivalent Sr(2), one Sc(1), one Sc(2), and one Sc(3) atom to form distorted NSr3Sc3 octahedra that share corners with three equivalent N(4)Sr2Sc3 square pyramids,  an edgeedge with one N(1)Sr3Sc3 octahedra, and  an edgeedge with one N(4)Sr2Sc3 square pyramid. In the second N site, N(2) is bonded in a 5-coordinate geometry to one Sr(3), two equivalent Sr(1), one Sc(2), and one Sc(3) atom. In the third N site, N(3) is bonded in a 6-coordinate geometry to one Sr(1), one Sr(2), two equivalent Sr(3), and two equivalent Sc(1) atoms. In the fourth N site, N(4) is bonded to one Sr(1), one Sr(2), one Sc(3), and two equivalent Sc(2) atoms to form distorted NSr2Sc3 square pyramids that share corners with three equivalent N(1)Sr3Sc3 octahedra,  an edgeedge with one N(1)Sr3Sc3 octahedra, and  an edgeedge with one N(4)Sr2Sc3 square pyramid. The corner-sharing octahedral tilt angles range from 18-62°. In the fifth N site, N(5) is bonded in a 5-coordinate geometry to one Sr(3), two equivalent Sr(2), one Sc(1), and one Sc(3) atom.