Si6Sb3N11 crystallizes in the tetragonal P4bm space group. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded to one N(2), one N(3), and two equivalent N(1) atoms to form corner-sharing SiN4 tetrahedra. In the second Si site, Si(2) is bonded to one N(3), one N(4), and two equivalent N(2) atoms to form corner-sharing SiN4 tetrahedra. There are two inequivalent Sb sites. In the first Sb site, Sb(1) is bonded in a 6-coordinate geometry to one N(3), one N(4), two equivalent N(1), and two equivalent N(2) atoms. In the second Sb site, Sb(2) is bonded in a 8-coordinate geometry to four equivalent N(1) and four equivalent N(2) atoms. There are four inequivalent N sites. In the first N site, N(3) is bonded in a distorted trigonal planar geometry to one Si(2), two equivalent Si(1), and one Sb(1) atom. In the second N site, N(4) is bonded in a linear geometry to two equivalent Si(2) and two equivalent Sb(1) atoms. In the third N site, N(1) is bonded to two equivalent Si(1), one Sb(1), and one Sb(2) atom to form a mixture of distorted edge and corner-sharing NSi2Sb2 trigonal pyramids. In the fourth N site, N(2) is bonded in a distorted bent 120 degrees geometry to one Si(1), one Si(2), one Sb(1), and one Sb(2) atom.
Si6Sb3N11 crystallizes in the tetragonal P4bm space group. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded to one N(2), one N(3), and two equivalent N(1) atoms to form corner-sharing SiN4 tetrahedra. The Si(1)-N(2) bond length is 1.70 Å. The Si(1)-N(3) bond length is 1.79 Å. There is one shorter (1.75 Å) and one longer (1.77 Å) Si(1)-N(1) bond length. In the second Si site, Si(2) is bonded to one N(3), one N(4), and two equivalent N(2) atoms to form corner-sharing SiN4 tetrahedra. The Si(2)-N(3) bond length is 1.80 Å. The Si(2)-N(4) bond length is 1.68 Å. Both Si(2)-N(2) bond lengths are 1.74 Å. There are two inequivalent Sb sites. In the first Sb site, Sb(1) is bonded in a 6-coordinate geometry to one N(3), one N(4), two equivalent N(1), and two equivalent N(2) atoms. The Sb(1)-N(3) bond length is 2.44 Å. The Sb(1)-N(4) bond length is 2.75 Å. Both Sb(1)-N(1) bond lengths are 2.29 Å. Both Sb(1)-N(2) bond lengths are 2.67 Å. In the second Sb site, Sb(2) is bonded in a 8-coordinate geometry to four equivalent N(1) and four equivalent N(2) atoms. All Sb(2)-N(1) bond lengths are 2.48 Å. All Sb(2)-N(2) bond lengths are 2.69 Å. There are four inequivalent N sites. In the first N site, N(3) is bonded in a distorted trigonal planar geometry to one Si(2), two equivalent Si(1), and one Sb(1) atom. In the second N site, N(4) is bonded in a linear geometry to two equivalent Si(2) and two equivalent Sb(1) atoms. In the third N site, N(1) is bonded to two equivalent Si(1), one Sb(1), and one Sb(2) atom to form a mixture of distorted edge and corner-sharing NSi2Sb2 trigonal pyramids. In the fourth N site, N(2) is bonded in a distorted bent 120 degrees geometry to one Si(1), one Si(2), one Sb(1), and one Sb(2) atom.