La4MnSe6O crystallizes in the hexagonal P6_3mc space group. There are two inequivalent La sites. In the first La site, La(1) is bonded in a 1-coordinate geometry to three equivalent Se(2), six equivalent Se(1), and one O(1) atom. In the second La site, La(2) is bonded in a distorted single-bond geometry to three equivalent Se(2), four equivalent Se(1), and one O(1) atom. Mn(1) is bonded to six equivalent Se(2) atoms to form face-sharing MnSe6 octahedra. There are two inequivalent Se sites. In the first Se site, Se(1) is bonded in a 6-coordinate geometry to two equivalent La(1) and four equivalent La(2) atoms. In the second Se site, Se(2) is bonded in a 6-coordinate geometry to one La(1), three equivalent La(2), and two equivalent Mn(1) atoms. O(1) is bonded in a tetrahedral geometry to one La(1) and three equivalent La(2) atoms.
La4MnSe6O crystallizes in the hexagonal P6_3mc space group. There are two inequivalent La sites. In the first La site, La(1) is bonded in a 1-coordinate geometry to three equivalent Se(2), six equivalent Se(1), and one O(1) atom. All La(1)-Se(2) bond lengths are 3.55 Å. There are three shorter (2.99 Å) and three longer (3.76 Å) La(1)-Se(1) bond lengths. The La(1)-O(1) bond length is 2.40 Å. In the second La site, La(2) is bonded in a distorted single-bond geometry to three equivalent Se(2), four equivalent Se(1), and one O(1) atom. There are two shorter (3.08 Å) and one longer (3.11 Å) La(2)-Se(2) bond length. There are two shorter (3.06 Å) and two longer (3.34 Å) La(2)-Se(1) bond lengths. The La(2)-O(1) bond length is 2.42 Å. Mn(1) is bonded to six equivalent Se(2) atoms to form face-sharing MnSe6 octahedra. There are three shorter (2.71 Å) and three longer (2.88 Å) Mn(1)-Se(2) bond lengths. There are two inequivalent Se sites. In the first Se site, Se(1) is bonded in a 6-coordinate geometry to two equivalent La(1) and four equivalent La(2) atoms. In the second Se site, Se(2) is bonded in a 6-coordinate geometry to one La(1), three equivalent La(2), and two equivalent Mn(1) atoms. O(1) is bonded in a tetrahedral geometry to one La(1) and three equivalent La(2) atoms.