Sm3Si6N11 crystallizes in the tetragonal P4bm space group. There are two inequivalent Sm sites. In the first Sm site, Sm(1) is bonded in a 8-coordinate geometry to four equivalent N(3) and four equivalent N(4) atoms. In the second Sm site, Sm(2) is bonded in a 8-coordinate geometry to one N(1), one N(2), two equivalent N(4), and four equivalent N(3) atoms. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded to one N(1), one N(2), and two equivalent N(3) atoms to form corner-sharing SiN4 tetrahedra. In the second Si site, Si(2) is bonded to one N(2), one N(3), and two equivalent N(4) atoms to form corner-sharing SiN4 tetrahedra. There are four inequivalent N sites. In the first N site, N(4) is bonded to one Sm(1), one Sm(2), and two equivalent Si(2) atoms to form a mixture of distorted edge and corner-sharing NSm2Si2 trigonal pyramids. In the second N site, N(1) is bonded in a distorted rectangular see-saw-like geometry to two equivalent Sm(2) and two equivalent Si(1) atoms. In the third N site, N(2) is bonded in a trigonal planar geometry to one Sm(2), one Si(1), and two equivalent Si(2) atoms. In the fourth N site, N(3) is bonded in a 2-coordinate geometry to one Sm(1), two equivalent Sm(2), one Si(1), and one Si(2) atom.
Sm3Si6N11 crystallizes in the tetragonal P4bm space group. There are two inequivalent Sm sites. In the first Sm site, Sm(1) is bonded in a 8-coordinate geometry to four equivalent N(3) and four equivalent N(4) atoms. All Sm(1)-N(3) bond lengths are 2.58 Å. All Sm(1)-N(4) bond lengths are 2.56 Å. In the second Sm site, Sm(2) is bonded in a 8-coordinate geometry to one N(1), one N(2), two equivalent N(4), and four equivalent N(3) atoms. The Sm(2)-N(1) bond length is 2.60 Å. The Sm(2)-N(2) bond length is 2.75 Å. Both Sm(2)-N(4) bond lengths are 2.42 Å. There are two shorter (2.60 Å) and two longer (2.89 Å) Sm(2)-N(3) bond lengths. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded to one N(1), one N(2), and two equivalent N(3) atoms to form corner-sharing SiN4 tetrahedra. The Si(1)-N(1) bond length is 1.68 Å. The Si(1)-N(2) bond length is 1.76 Å. Both Si(1)-N(3) bond lengths are 1.73 Å. In the second Si site, Si(2) is bonded to one N(2), one N(3), and two equivalent N(4) atoms to form corner-sharing SiN4 tetrahedra. The Si(2)-N(2) bond length is 1.76 Å. The Si(2)-N(3) bond length is 1.73 Å. There is one shorter (1.71 Å) and one longer (1.73 Å) Si(2)-N(4) bond length. There are four inequivalent N sites. In the first N site, N(4) is bonded to one Sm(1), one Sm(2), and two equivalent Si(2) atoms to form a mixture of distorted edge and corner-sharing NSm2Si2 trigonal pyramids. In the second N site, N(1) is bonded in a distorted rectangular see-saw-like geometry to two equivalent Sm(2) and two equivalent Si(1) atoms. In the third N site, N(2) is bonded in a trigonal planar geometry to one Sm(2), one Si(1), and two equivalent Si(2) atoms. In the fourth N site, N(3) is bonded in a 2-coordinate geometry to one Sm(1), two equivalent Sm(2), one Si(1), and one Si(2) atom.