K3Si3N5 crystallizes in the triclinic P-1 space group. There are three inequivalent K sites. In the first K site, K(1) is bonded in a 6-coordinate geometry to one N(1), one N(3), one N(4), one N(5), and two equivalent N(2) atoms. In the second K site, K(2) is bonded in a 3-coordinate geometry to one N(3) and two equivalent N(5) atoms. In the third K site, K(3) is bonded in a 5-coordinate geometry to one N(1), one N(2), one N(4), 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 corner and edge-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 corner and edge-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 corner and edge-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 K(1), one K(3), one Si(1), one Si(2), and one Si(3) atom. In the second N site, N(2) is bonded in a 2-coordinate geometry to one K(3), two equivalent K(1), one Si(2), and one Si(3) atom. In the third N site, N(3) is bonded in a 6-coordinate geometry to one K(1), one K(2), two equivalent K(3), and two equivalent Si(1) atoms. In the fourth N site, N(4) is bonded in a 3-coordinate geometry to one K(1), one K(3), one Si(3), and two equivalent Si(2) atoms. In the fifth N site, N(5) is bonded in a 2-coordinate geometry to one K(1), two equivalent K(2), one Si(1), and one Si(3) atom.
K3Si3N5 crystallizes in the triclinic P-1 space group. There are three inequivalent K sites. In the first K site, K(1) is bonded in a 6-coordinate geometry to one N(1), one N(3), one N(4), one N(5), and two equivalent N(2) atoms. The K(1)-N(1) bond length is 2.97 Å. The K(1)-N(3) bond length is 2.68 Å. The K(1)-N(4) bond length is 2.83 Å. The K(1)-N(5) bond length is 3.04 Å. There is one shorter (2.64 Å) and one longer (2.93 Å) K(1)-N(2) bond length. In the second K site, K(2) is bonded in a 3-coordinate geometry to one N(3) and two equivalent N(5) atoms. The K(2)-N(3) bond length is 2.70 Å. There is one shorter (2.63 Å) and one longer (2.80 Å) K(2)-N(5) bond length. In the third K site, K(3) is bonded in a 5-coordinate geometry to one N(1), one N(2), one N(4), and two equivalent N(3) atoms. The K(3)-N(1) bond length is 2.81 Å. The K(3)-N(2) bond length is 2.62 Å. The K(3)-N(4) bond length is 2.96 Å. There is one shorter (2.59 Å) and one longer (2.60 Å) K(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 corner and edge-sharing SiN4 tetrahedra. The Si(1)-N(1) bond length is 1.89 Å. The Si(1)-N(5) bond length is 1.74 Å. There is one shorter (1.75 Å) and one longer (1.78 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 corner and edge-sharing SiN4 tetrahedra. The Si(2)-N(1) bond length is 1.83 Å. The Si(2)-N(2) bond length is 1.71 Å. There is one shorter (1.83 Å) and one longer (1.85 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 corner and edge-sharing SiN4 tetrahedra. The Si(3)-N(1) bond length is 1.91 Å. The Si(3)-N(2) bond length is 1.74 Å. The Si(3)-N(4) bond length is 1.90 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 K(1), one K(3), one Si(1), one Si(2), and one Si(3) atom. In the second N site, N(2) is bonded in a 2-coordinate geometry to one K(3), two equivalent K(1), one Si(2), and one Si(3) atom. In the third N site, N(3) is bonded in a 6-coordinate geometry to one K(1), one K(2), two equivalent K(3), and two equivalent Si(1) atoms. In the fourth N site, N(4) is bonded in a 3-coordinate geometry to one K(1), one K(3), one Si(3), and two equivalent Si(2) atoms. In the fifth N site, N(5) is bonded in a 2-coordinate geometry to one K(1), two equivalent K(2), one Si(1), and one Si(3) atom.