LaP5 crystallizes in the monoclinic P2_1/m space group. There are two inequivalent La sites. In the first La site, La(1) is bonded in a 10-coordinate geometry to two equivalent P(3), two equivalent P(5), two equivalent P(6), and four equivalent P(2) atoms. In the second La site, La(2) is bonded in a 8-coordinate geometry to two equivalent P(1), two equivalent P(4), and four equivalent P(5) atoms. There are six inequivalent P sites. In the first P site, P(1) is bonded to one La(2), one P(3), one P(5), and one P(6) atom to form distorted PLaP3 tetrahedra that share corners with three equivalent P(4)La2P2 tetrahedra and  an edgeedge with one P(1)LaP3 tetrahedra. In the second P site, P(2) is bonded in a 4-coordinate geometry to two equivalent La(1), one P(3), and one P(5) atom. In the third P site, P(3) is bonded to one La(1), one P(1), one P(2), and one P(4) atom to form edge-sharing PLaP3 tetrahedra. In the fourth P site, P(4) is bonded to two equivalent La(2) and two equivalent P(3) atoms to form distorted PLa2P2 tetrahedra that share corners with two equivalent P(4)La2P2 tetrahedra and corners with six equivalent P(1)LaP3 tetrahedra. In the fifth P site, P(5) is bonded in a 5-coordinate geometry to one La(1), two equivalent La(2), one P(1), and one P(2) atom. In the sixth P site, P(6) is bonded in a rectangular see-saw-like geometry to two equivalent La(1) and two equivalent P(1) atoms.
LaP5 crystallizes in the monoclinic P2_1/m space group. There are two inequivalent La sites. In the first La site, La(1) is bonded in a 10-coordinate geometry to two equivalent P(3), two equivalent P(5), two equivalent P(6), and four equivalent P(2) atoms. Both La(1)-P(3) bond lengths are 3.18 Å. Both La(1)-P(5) bond lengths are 3.38 Å. There is one shorter (2.96 Å) and one longer (2.99 Å) La(1)-P(6) bond length. There are two shorter (3.06 Å) and two longer (3.16 Å) La(1)-P(2) bond lengths. In the second La site, La(2) is bonded in a 8-coordinate geometry to two equivalent P(1), two equivalent P(4), and four equivalent P(5) atoms. Both La(2)-P(1) bond lengths are 3.08 Å. There is one shorter (2.99 Å) and one longer (3.04 Å) La(2)-P(4) bond length. There are two shorter (3.13 Å) and two longer (3.14 Å) La(2)-P(5) bond lengths. There are six inequivalent P sites. In the first P site, P(1) is bonded to one La(2), one P(3), one P(5), and one P(6) atom to form distorted PLaP3 tetrahedra that share corners with three equivalent P(4)La2P2 tetrahedra and  an edgeedge with one P(1)LaP3 tetrahedra. The P(1)-P(3) bond length is 2.22 Å. The P(1)-P(5) bond length is 2.19 Å. The P(1)-P(6) bond length is 2.23 Å. In the second P site, P(2) is bonded in a 4-coordinate geometry to two equivalent La(1), one P(3), and one P(5) atom. The P(2)-P(3) bond length is 2.19 Å. The P(2)-P(5) bond length is 2.23 Å. In the third P site, P(3) is bonded to one La(1), one P(1), one P(2), and one P(4) atom to form edge-sharing PLaP3 tetrahedra. The P(3)-P(4) bond length is 2.22 Å. In the fourth P site, P(4) is bonded to two equivalent La(2) and two equivalent P(3) atoms to form distorted PLa2P2 tetrahedra that share corners with two equivalent P(4)La2P2 tetrahedra and corners with six equivalent P(1)LaP3 tetrahedra. In the fifth P site, P(5) is bonded in a 5-coordinate geometry to one La(1), two equivalent La(2), one P(1), and one P(2) atom. In the sixth P site, P(6) is bonded in a rectangular see-saw-like geometry to two equivalent La(1) and two equivalent P(1) atoms.