Na3Si3N5 crystallizes in the triclinic P-1 space group. There are three inequivalent Na sites. In the first Na site, Na(1) is bonded in a 4-coordinate geometry to one N(3), one N(4), and two equivalent N(2) atoms. In the second Na site, Na(2) is bonded in a 3-coordinate geometry to one N(3) and two equivalent N(5) atoms. In the third Na site, Na(3) is bonded in a 6-coordinate geometry to one N(1), one N(2), one N(4), one N(5), and two equivalent N(3) atoms. There are three inequivalent Si sites. In the first Si site, Si(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 SiN4 tetrahedra. In the second Si site, Si(2) is bonded to one N(1), one N(2), and two equivalent N(4) atoms to form a mixture of distorted edge and corner-sharing SiN4 tetrahedra. In the third Si site, Si(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 SiN4 tetrahedra. There are five inequivalent N sites. In the first N site, N(1) is bonded in a 3-coordinate geometry to one Na(3), one Si(1), one Si(2), and one Si(3) atom. In the second N site, N(2) is bonded in a 5-coordinate geometry to one Na(3), two equivalent Na(1), one Si(2), and one Si(3) atom. In the third N site, N(3) is bonded to one Na(1), one Na(2), two equivalent Na(3), and two equivalent Si(1) atoms to form edge-sharing NNa4Si2 octahedra. In the fourth N site, N(4) is bonded in a 3-coordinate geometry to one Na(1), one Na(3), one Si(3), and two equivalent Si(2) atoms. In the fifth N site, N(5) is bonded in a 4-coordinate geometry to one Na(3), two equivalent Na(2), one Si(1), and one Si(3) atom.
Na3Si3N5 crystallizes in the triclinic P-1 space group. There are three inequivalent Na sites. In the first Na site, Na(1) is bonded in a 4-coordinate geometry to one N(3), one N(4), and two equivalent N(2) atoms. The Na(1)-N(3) bond length is 2.40 Å. The Na(1)-N(4) bond length is 2.60 Å. There is one shorter (2.34 Å) and one longer (2.55 Å) Na(1)-N(2) bond length. In the second Na site, Na(2) is bonded in a 3-coordinate geometry to one N(3) and two equivalent N(5) atoms. The Na(2)-N(3) bond length is 2.43 Å. There is one shorter (2.33 Å) and one longer (2.53 Å) Na(2)-N(5) bond length. In the third Na site, Na(3) is bonded in a 6-coordinate geometry to one N(1), one N(2), one N(4), one N(5), and two equivalent N(3) atoms. The Na(3)-N(1) bond length is 2.69 Å. The Na(3)-N(2) bond length is 2.48 Å. The Na(3)-N(4) bond length is 2.86 Å. The Na(3)-N(5) bond length is 2.90 Å. There is one shorter (2.36 Å) and one longer (2.43 Å) Na(3)-N(3) bond length. There are three inequivalent Si sites. In the first Si site, Si(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 SiN4 tetrahedra. The Si(1)-N(1) bond length is 1.80 Å. The Si(1)-N(5) bond length is 1.73 Å. There is one shorter (1.76 Å) and one longer (1.77 Å) Si(1)-N(3) bond length. In the second Si site, Si(2) is bonded to one N(1), one N(2), and two equivalent N(4) atoms to form a mixture of distorted edge and corner-sharing SiN4 tetrahedra. The Si(2)-N(1) bond length is 1.77 Å. The Si(2)-N(2) bond length is 1.71 Å. There is one shorter (1.79 Å) and one longer (1.80 Å) Si(2)-N(4) bond length. In the third Si site, Si(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 SiN4 tetrahedra. The Si(3)-N(1) bond length is 1.84 Å. The Si(3)-N(2) bond length is 1.76 Å. The Si(3)-N(4) bond length is 1.82 Å. The Si(3)-N(5) bond length is 1.69 Å. There are five inequivalent N sites. In the first N site, N(1) is bonded in a 3-coordinate geometry to one Na(3), one Si(1), one Si(2), and one Si(3) atom. In the second N site, N(2) is bonded in a 5-coordinate geometry to one Na(3), two equivalent Na(1), one Si(2), and one Si(3) atom. In the third N site, N(3) is bonded to one Na(1), one Na(2), two equivalent Na(3), and two equivalent Si(1) atoms to form edge-sharing NNa4Si2 octahedra. In the fourth N site, N(4) is bonded in a 3-coordinate geometry to one Na(1), one Na(3), one Si(3), and two equivalent Si(2) atoms. In the fifth N site, N(5) is bonded in a 4-coordinate geometry to one Na(3), two equivalent Na(2), one Si(1), and one Si(3) atom.