Cd7SiN6 is Ilmenite-like structured and crystallizes in the orthorhombic Cmcm space group. There are three inequivalent Cd sites. In the first Cd site, Cd(1) is bonded to two equivalent N(2) and two equivalent N(3) atoms to form distorted CdN4 trigonal pyramids that share corners with two equivalent Si(1)N4 tetrahedra, corners with eight equivalent Cd(2)N4 tetrahedra, edges with two equivalent Cd(2)N4 tetrahedra, and edges with two equivalent Cd(1)N4 trigonal pyramids. In the second Cd site, Cd(2) is bonded to one N(1), one N(3), and two equivalent N(2) atoms to form distorted CdN4 tetrahedra that share corners with two equivalent Si(1)N4 tetrahedra, corners with six equivalent Cd(2)N4 tetrahedra, corners with four equivalent Cd(1)N4 trigonal pyramids,  an edgeedge with one Cd(2)N4 tetrahedra, and  an edgeedge with one Cd(1)N4 trigonal pyramid. In the third Cd site, Cd(3) is bonded in a 4-coordinate geometry to two equivalent N(1) and two equivalent N(3) atoms. Si(1) is bonded to two equivalent N(1) and two equivalent N(3) atoms to form SiN4 tetrahedra that share corners with eight equivalent Cd(2)N4 tetrahedra and corners with four equivalent Cd(1)N4 trigonal pyramids. There are three inequivalent N sites. In the first N site, N(1) is bonded to one Cd(3), two equivalent Cd(2), and one Si(1) atom to form distorted NCd3Si tetrahedra that share corners with four equivalent N(2)Cd6 pentagonal pyramids and  an edgeedge with one N(1)Cd3Si tetrahedra. In the second N site, N(2) is bonded to two equivalent Cd(1) and four equivalent Cd(2) atoms to form distorted NCd6 pentagonal pyramids that share corners with four equivalent N(1)Cd3Si tetrahedra and edges with three equivalent N(2)Cd6 pentagonal pyramids. In the third N site, N(3) is bonded in a 6-coordinate geometry to one Cd(3), two equivalent Cd(1), two equivalent Cd(2), and one Si(1) atom.
Cd7SiN6 is Ilmenite-like structured and crystallizes in the orthorhombic Cmcm space group. There are three inequivalent Cd sites. In the first Cd site, Cd(1) is bonded to two equivalent N(2) and two equivalent N(3) atoms to form distorted CdN4 trigonal pyramids that share corners with two equivalent Si(1)N4 tetrahedra, corners with eight equivalent Cd(2)N4 tetrahedra, edges with two equivalent Cd(2)N4 tetrahedra, and edges with two equivalent Cd(1)N4 trigonal pyramids. Both Cd(1)-N(2) bond lengths are 2.32 Å. There is one shorter (2.41 Å) and one longer (2.64 Å) Cd(1)-N(3) bond length. In the second Cd site, Cd(2) is bonded to one N(1), one N(3), and two equivalent N(2) atoms to form distorted CdN4 tetrahedra that share corners with two equivalent Si(1)N4 tetrahedra, corners with six equivalent Cd(2)N4 tetrahedra, corners with four equivalent Cd(1)N4 trigonal pyramids,  an edgeedge with one Cd(2)N4 tetrahedra, and  an edgeedge with one Cd(1)N4 trigonal pyramid. The Cd(2)-N(1) bond length is 2.28 Å. The Cd(2)-N(3) bond length is 2.39 Å. There is one shorter (2.33 Å) and one longer (2.48 Å) Cd(2)-N(2) bond length. In the third Cd site, Cd(3) is bonded in a 4-coordinate geometry to two equivalent N(1) and two equivalent N(3) atoms. Both Cd(3)-N(1) bond lengths are 2.30 Å. Both Cd(3)-N(3) bond lengths are 2.48 Å. Si(1) is bonded to two equivalent N(1) and two equivalent N(3) atoms to form SiN4 tetrahedra that share corners with eight equivalent Cd(2)N4 tetrahedra and corners with four equivalent Cd(1)N4 trigonal pyramids. Both Si(1)-N(1) bond lengths are 1.78 Å. Both Si(1)-N(3) bond lengths are 1.79 Å. There are three inequivalent N sites. In the first N site, N(1) is bonded to one Cd(3), two equivalent Cd(2), and one Si(1) atom to form distorted NCd3Si tetrahedra that share corners with four equivalent N(2)Cd6 pentagonal pyramids and  an edgeedge with one N(1)Cd3Si tetrahedra. In the second N site, N(2) is bonded to two equivalent Cd(1) and four equivalent Cd(2) atoms to form distorted NCd6 pentagonal pyramids that share corners with four equivalent N(1)Cd3Si tetrahedra and edges with three equivalent N(2)Cd6 pentagonal pyramids. In the third N site, N(3) is bonded in a 6-coordinate geometry to one Cd(3), two equivalent Cd(1), two equivalent Cd(2), and one Si(1) atom.