Si7CN10 crystallizes in the monoclinic Pc space group. There are seven inequivalent Si sites. In the first Si site, Si(1) is bonded to one N(1), one N(2), one N(3), and one N(6) atom to form a mixture of corner and edge-sharing SiN4 tetrahedra. In the second Si site, Si(2) is bonded to one N(2), one N(3), one N(4), and one N(6) atom to form a mixture of corner and edge-sharing SiN4 tetrahedra. In the third Si site, Si(3) is bonded to one C(1), one N(5), one N(7), and one N(8) atom to form corner-sharing SiCN3 tetrahedra. In the fourth Si site, Si(4) is bonded to one N(10), one N(2), one N(7), and one N(9) atom to form SiN4 tetrahedra that share  a cornercorner with one Si(3)CN3 tetrahedra,  a cornercorner with one Si(1)N4 tetrahedra,  a cornercorner with one Si(2)N4 tetrahedra,  a cornercorner with one Si(6)N4 tetrahedra, corners with two equivalent Si(5)N4 tetrahedra, and corners with two equivalent Si(7)N4 tetrahedra. In the fifth Si site, Si(5) is bonded to one N(1), one N(7), one N(8), and one N(9) atom to form SiN4 tetrahedra that share  a cornercorner with one Si(1)N4 tetrahedra,  a cornercorner with one Si(6)N4 tetrahedra,  a cornercorner with one Si(7)N4 tetrahedra, corners with two equivalent Si(3)CN3 tetrahedra, and corners with two equivalent Si(4)N4 tetrahedra. In the sixth Si site, Si(6) is bonded to one N(10), one N(3), one N(5), and one N(8) atom to form SiN4 tetrahedra that share  a cornercorner with one Si(1)N4 tetrahedra,  a cornercorner with one Si(2)N4 tetrahedra,  a cornercorner with one Si(4)N4 tetrahedra,  a cornercorner with one Si(5)N4 tetrahedra, corners with two equivalent Si(3)CN3 tetrahedra, and corners with two equivalent Si(7)N4 tetrahedra. In the seventh Si site, Si(7) is bonded to one N(10), one N(5), one N(6), and one N(9) atom to form SiN4 tetrahedra that share  a cornercorner with one Si(3)CN3 tetrahedra,  a cornercorner with one Si(1)N4 tetrahedra,  a cornercorner with one Si(2)N4 tetrahedra,  a cornercorner with one Si(5)N4 tetrahedra, corners with two equivalent Si(4)N4 tetrahedra, and corners with two equivalent Si(6)N4 tetrahedra. C(1) is bonded in a linear geometry to one Si(3) and one N(4) atom. There are ten inequivalent N sites. In the first N site, N(9) is bonded in a trigonal planar geometry to one Si(4), one Si(5), and one Si(7) atom. In the second N site, N(10) is bonded in a trigonal planar geometry to one Si(4), one Si(6), and one Si(7) atom. In the third N site, N(1) is bonded in a bent 150 degrees geometry to one Si(1) and one Si(5) atom. In the fourth N site, N(2) is bonded in a distorted T-shaped geometry to one Si(1), one Si(2), and one Si(4) atom. In the fifth N site, N(3) is bonded in a distorted T-shaped geometry to one Si(1), one Si(2), and one Si(6) atom. In the sixth N site, N(4) is bonded in a bent 150 degrees geometry to one Si(2) and one C(1) atom. In the seventh N site, N(5) is bonded in a trigonal planar geometry to one Si(3), one Si(6), and one Si(7) atom. In the eighth N site, N(6) is bonded in a trigonal planar geometry to one Si(1), one Si(2), and one Si(7) atom. In the ninth N site, N(7) is bonded in a trigonal planar geometry to one Si(3), one Si(4), and one Si(5) atom. In the tenth N site, N(8) is bonded in a trigonal planar geometry to one Si(3), one Si(5), and one Si(6) atom.
Si7CN10 crystallizes in the monoclinic Pc space group. There are seven inequivalent Si sites. In the first Si site, Si(1) is bonded to one N(1), one N(2), one N(3), and one N(6) atom to form a mixture of corner and edge-sharing SiN4 tetrahedra. The Si(1)-N(1) bond length is 1.63 Å. The Si(1)-N(2) bond length is 1.80 Å. The Si(1)-N(3) bond length is 1.83 Å. The Si(1)-N(6) bond length is 1.77 Å. In the second Si site, Si(2) is bonded to one N(2), one N(3), one N(4), and one N(6) atom to form a mixture of corner and edge-sharing SiN4 tetrahedra. The Si(2)-N(2) bond length is 1.72 Å. The Si(2)-N(3) bond length is 1.71 Å. The Si(2)-N(4) bond length is 1.78 Å. The Si(2)-N(6) bond length is 1.69 Å. In the third Si site, Si(3) is bonded to one C(1), one N(5), one N(7), and one N(8) atom to form corner-sharing SiCN3 tetrahedra. The Si(3)-C(1) bond length is 1.87 Å. The Si(3)-N(5) bond length is 1.72 Å. The Si(3)-N(7) bond length is 1.71 Å. The Si(3)-N(8) bond length is 1.74 Å. In the fourth Si site, Si(4) is bonded to one N(10), one N(2), one N(7), and one N(9) atom to form SiN4 tetrahedra that share  a cornercorner with one Si(3)CN3 tetrahedra,  a cornercorner with one Si(1)N4 tetrahedra,  a cornercorner with one Si(2)N4 tetrahedra,  a cornercorner with one Si(6)N4 tetrahedra, corners with two equivalent Si(5)N4 tetrahedra, and corners with two equivalent Si(7)N4 tetrahedra. The Si(4)-N(10) bond length is 1.75 Å. The Si(4)-N(2) bond length is 1.74 Å. The Si(4)-N(7) bond length is 1.75 Å. The Si(4)-N(9) bond length is 1.75 Å. In the fifth Si site, Si(5) is bonded to one N(1), one N(7), one N(8), and one N(9) atom to form SiN4 tetrahedra that share  a cornercorner with one Si(1)N4 tetrahedra,  a cornercorner with one Si(6)N4 tetrahedra,  a cornercorner with one Si(7)N4 tetrahedra, corners with two equivalent Si(3)CN3 tetrahedra, and corners with two equivalent Si(4)N4 tetrahedra. The Si(5)-N(1) bond length is 1.64 Å. The Si(5)-N(7) bond length is 1.81 Å. The Si(5)-N(8) bond length is 1.78 Å. The Si(5)-N(9) bond length is 1.78 Å. In the sixth Si site, Si(6) is bonded to one N(10), one N(3), one N(5), and one N(8) atom to form SiN4 tetrahedra that share  a cornercorner with one Si(1)N4 tetrahedra,  a cornercorner with one Si(2)N4 tetrahedra,  a cornercorner with one Si(4)N4 tetrahedra,  a cornercorner with one Si(5)N4 tetrahedra, corners with two equivalent Si(3)CN3 tetrahedra, and corners with two equivalent Si(7)N4 tetrahedra. The Si(6)-N(10) bond length is 1.75 Å. The Si(6)-N(3) bond length is 1.73 Å. The Si(6)-N(5) bond length is 1.75 Å. The Si(6)-N(8) bond length is 1.78 Å. In the seventh Si site, Si(7) is bonded to one N(10), one N(5), one N(6), and one N(9) atom to form SiN4 tetrahedra that share  a cornercorner with one Si(3)CN3 tetrahedra,  a cornercorner with one Si(1)N4 tetrahedra,  a cornercorner with one Si(2)N4 tetrahedra,  a cornercorner with one Si(5)N4 tetrahedra, corners with two equivalent Si(4)N4 tetrahedra, and corners with two equivalent Si(6)N4 tetrahedra. The Si(7)-N(10) bond length is 1.75 Å. The Si(7)-N(5) bond length is 1.78 Å. The Si(7)-N(6) bond length is 1.74 Å. The Si(7)-N(9) bond length is 1.73 Å. C(1) is bonded in a linear geometry to one Si(3) and one N(4) atom. The C(1)-N(4) bond length is 1.16 Å. There are ten inequivalent N sites. In the first N site, N(9) is bonded in a trigonal planar geometry to one Si(4), one Si(5), and one Si(7) atom. In the second N site, N(10) is bonded in a trigonal planar geometry to one Si(4), one Si(6), and one Si(7) atom. In the third N site, N(1) is bonded in a bent 150 degrees geometry to one Si(1) and one Si(5) atom. In the fourth N site, N(2) is bonded in a distorted T-shaped geometry to one Si(1), one Si(2), and one Si(4) atom. In the fifth N site, N(3) is bonded in a distorted T-shaped geometry to one Si(1), one Si(2), and one Si(6) atom. In the sixth N site, N(4) is bonded in a bent 150 degrees geometry to one Si(2) and one C(1) atom. In the seventh N site, N(5) is bonded in a trigonal planar geometry to one Si(3), one Si(6), and one Si(7) atom. In the eighth N site, N(6) is bonded in a trigonal planar geometry to one Si(1), one Si(2), and one Si(7) atom. In the ninth N site, N(7) is bonded in a trigonal planar geometry to one Si(3), one Si(4), and one Si(5) atom. In the tenth N site, N(8) is bonded in a trigonal planar geometry to one Si(3), one Si(5), and one Si(6) atom.