La5Si3O13 crystallizes in the hexagonal P6_3/m space group. There are two inequivalent La sites. In the first La site, La(1) is bonded in a 9-coordinate geometry to three equivalent O(1), three equivalent O(3), and three equivalent O(4) atoms. In the second La site, La(2) is bonded in a 7-coordinate geometry to one O(1), one O(2), one O(3), and four equivalent O(4) atoms. Si(1) is bonded in a tetrahedral geometry to one O(1), one O(3), and two equivalent O(4) atoms. There are four inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to one La(2), two equivalent La(1), and one Si(1) atom. In the second O site, O(2) is bonded in a trigonal planar geometry to three equivalent La(2) atoms. In the third O site, O(3) is bonded in a 4-coordinate geometry to one La(2), two equivalent La(1), and one Si(1) atom. In the fourth O site, O(4) is bonded in a 1-coordinate geometry to one La(1), two equivalent La(2), and one Si(1) atom.
La5Si3O13 crystallizes in the hexagonal P6_3/m space group. There are two inequivalent La sites. In the first La site, La(1) is bonded in a 9-coordinate geometry to three equivalent O(1), three equivalent O(3), and three equivalent O(4) atoms. All La(1)-O(1) bond lengths are 2.50 Å. All La(1)-O(3) bond lengths are 2.59 Å. All La(1)-O(4) bond lengths are 2.92 Å. In the second La site, La(2) is bonded in a 7-coordinate geometry to one O(1), one O(2), one O(3), and four equivalent O(4) atoms. The La(2)-O(1) bond length is 2.77 Å. The La(2)-O(2) bond length is 2.33 Å. The La(2)-O(3) bond length is 2.54 Å. There are two shorter (2.50 Å) and two longer (2.61 Å) La(2)-O(4) bond lengths. Si(1) is bonded in a tetrahedral geometry to one O(1), one O(3), and two equivalent O(4) atoms. The Si(1)-O(1) bond length is 1.64 Å. The Si(1)-O(3) bond length is 1.65 Å. Both Si(1)-O(4) bond lengths are 1.66 Å. There are four inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to one La(2), two equivalent La(1), and one Si(1) atom. In the second O site, O(2) is bonded in a trigonal planar geometry to three equivalent La(2) atoms. In the third O site, O(3) is bonded in a 4-coordinate geometry to one La(2), two equivalent La(1), and one Si(1) atom. In the fourth O site, O(4) is bonded in a 1-coordinate geometry to one La(1), two equivalent La(2), and one Si(1) atom.