Zn5(SiN3)2 crystallizes in the monoclinic C2/c space group. There are three inequivalent Zn sites. In the first Zn site, Zn(1) is bonded to two equivalent N(1) and two equivalent N(3) atoms to form distorted ZnN4 tetrahedra that share corners with four equivalent Si(1)N4 tetrahedra. In the second Zn site, Zn(2) is bonded in a distorted trigonal planar geometry to one N(3) and two equivalent N(2) atoms. In the third Zn site, Zn(3) is bonded in a 4-coordinate geometry to two equivalent N(1) and two equivalent N(3) atoms. Si(1) is bonded to one N(1), one N(3), and two equivalent N(2) atoms to form SiN4 tetrahedra that share corners with two equivalent Zn(1)N4 tetrahedra and  an edgeedge with one Si(1)N4 tetrahedra. There are three inequivalent N sites. In the first N site, N(2) is bonded in a distorted rectangular see-saw-like geometry to two equivalent Zn(2) and two equivalent Si(1) atoms. In the second N site, N(3) is bonded in a 5-coordinate geometry to one Zn(1), one Zn(2), two equivalent Zn(3), and one Si(1) atom. In the third N site, N(1) is bonded to one Zn(1), two equivalent Zn(3), and one Si(1) atom to form corner-sharing NZn3Si tetrahedra.
Zn5(SiN3)2 crystallizes in the monoclinic C2/c space group. There are three inequivalent Zn sites. In the first Zn site, Zn(1) is bonded to two equivalent N(1) and two equivalent N(3) atoms to form distorted ZnN4 tetrahedra that share corners with four equivalent Si(1)N4 tetrahedra. Both Zn(1)-N(1) bond lengths are 2.04 Å. Both Zn(1)-N(3) bond lengths are 2.17 Å. In the second Zn site, Zn(2) is bonded in a distorted trigonal planar geometry to one N(3) and two equivalent N(2) atoms. The Zn(2)-N(3) bond length is 1.91 Å. There is one shorter (2.00 Å) and one longer (2.05 Å) Zn(2)-N(2) bond length. In the third Zn site, Zn(3) is bonded in a 4-coordinate geometry to two equivalent N(1) and two equivalent N(3) atoms. There is one shorter (1.97 Å) and one longer (2.05 Å) Zn(3)-N(1) bond length. There is one shorter (2.13 Å) and one longer (2.32 Å) Zn(3)-N(3) bond length. Si(1) is bonded to one N(1), one N(3), and two equivalent N(2) atoms to form SiN4 tetrahedra that share corners with two equivalent Zn(1)N4 tetrahedra and  an edgeedge with one Si(1)N4 tetrahedra. The Si(1)-N(1) bond length is 1.74 Å. The Si(1)-N(3) bond length is 1.74 Å. Both Si(1)-N(2) bond lengths are 1.80 Å. There are three inequivalent N sites. In the first N site, N(2) is bonded in a distorted rectangular see-saw-like geometry to two equivalent Zn(2) and two equivalent Si(1) atoms. In the second N site, N(3) is bonded in a 5-coordinate geometry to one Zn(1), one Zn(2), two equivalent Zn(3), and one Si(1) atom. In the third N site, N(1) is bonded to one Zn(1), two equivalent Zn(3), and one Si(1) atom to form corner-sharing NZn3Si tetrahedra.