La2Si4N6C crystallizes in the orthorhombic Pnma space group. There are two inequivalent La sites. In the first La site, La(1) is bonded in a 5-coordinate geometry to one N(1), two equivalent N(2), and two equivalent N(3) atoms. In the second La site, La(2) is bonded in a 7-coordinate geometry to two equivalent N(2), two equivalent N(3), and three equivalent N(4) atoms. There are three inequivalent Si sites. In the first Si site, Si(1) is bonded in a water-like geometry to two equivalent N(3) atoms. In the second Si site, Si(2) is bonded in a bent 120 degrees geometry to one N(1) and one N(2) atom. In the third Si site, Si(3) is bonded in a water-like geometry to two equivalent N(2) atoms. C(1) is bonded in a trigonal planar geometry to one N(4) and two equivalent N(3) atoms. There are four inequivalent N sites. In the first N site, N(3) is bonded in a 4-coordinate geometry to one La(1), one La(2), one Si(1), and one C(1) atom. In the second N site, N(4) is bonded in a 4-coordinate geometry to three equivalent La(2) and one C(1) atom. In the third N site, N(1) is bonded in a distorted trigonal planar geometry to one La(1) and two equivalent Si(2) atoms. In the fourth N site, N(2) is bonded in a 4-coordinate geometry to one La(1), one La(2), one Si(2), and one Si(3) atom.
La2Si4N6C crystallizes in the orthorhombic Pnma space group. There are two inequivalent La sites. In the first La site, La(1) is bonded in a 5-coordinate geometry to one N(1), two equivalent N(2), and two equivalent N(3) atoms. The La(1)-N(1) bond length is 2.48 Å. Both La(1)-N(2) bond lengths are 2.49 Å. Both La(1)-N(3) bond lengths are 2.57 Å. In the second La site, La(2) is bonded in a 7-coordinate geometry to two equivalent N(2), two equivalent N(3), and three equivalent N(4) atoms. Both La(2)-N(2) bond lengths are 2.80 Å. Both La(2)-N(3) bond lengths are 2.59 Å. There is one shorter (2.34 Å) and two longer (2.78 Å) La(2)-N(4) bond lengths. There are three inequivalent Si sites. In the first Si site, Si(1) is bonded in a water-like geometry to two equivalent N(3) atoms. Both Si(1)-N(3) bond lengths are 1.78 Å. In the second Si site, Si(2) is bonded in a bent 120 degrees geometry to one N(1) and one N(2) atom. The Si(2)-N(1) bond length is 1.73 Å. The Si(2)-N(2) bond length is 1.71 Å. In the third Si site, Si(3) is bonded in a water-like geometry to two equivalent N(2) atoms. Both Si(3)-N(2) bond lengths are 1.72 Å. C(1) is bonded in a trigonal planar geometry to one N(4) and two equivalent N(3) atoms. The C(1)-N(4) bond length is 1.32 Å. Both C(1)-N(3) bond lengths are 1.41 Å. There are four inequivalent N sites. In the first N site, N(3) is bonded in a 4-coordinate geometry to one La(1), one La(2), one Si(1), and one C(1) atom. In the second N site, N(4) is bonded in a 4-coordinate geometry to three equivalent La(2) and one C(1) atom. In the third N site, N(1) is bonded in a distorted trigonal planar geometry to one La(1) and two equivalent Si(2) atoms. In the fourth N site, N(2) is bonded in a 4-coordinate geometry to one La(1), one La(2), one Si(2), and one Si(3) atom.