NaEu2AlP3 crystallizes in the monoclinic C2/m space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded in a 2-coordinate geometry to two equivalent P(1), two equivalent P(2), and two equivalent P(4) atoms. In the second Na site, Na(2) is bonded in a 4-coordinate geometry to one P(4), one P(5), and two equivalent P(1) atoms. There are three inequivalent Eu sites. In the first Eu site, Eu(1) is bonded in a 7-coordinate geometry to one P(1), one P(2), one P(4), two equivalent P(3), and two equivalent P(5) atoms. In the second Eu site, Eu(2) is bonded to two equivalent P(1), two equivalent P(3), and two equivalent P(5) atoms to form EuP6 octahedra that share corners with two equivalent Eu(3)P6 octahedra, corners with two equivalent Al(1)P4 tetrahedra, edges with two equivalent Eu(2)P6 octahedra, and edges with two equivalent Al(2)P4 tetrahedra. The corner-sharing octahedral tilt angles are 38°. In the third Eu site, Eu(3) is bonded to two equivalent P(1), two equivalent P(2), and two equivalent P(4) atoms to form distorted EuP6 octahedra that share corners with two equivalent Eu(2)P6 octahedra, corners with two equivalent Al(1)P4 tetrahedra, edges with two equivalent Eu(3)P6 octahedra, edges with two equivalent Al(1)P4 tetrahedra, and edges with two equivalent Al(2)P4 tetrahedra. The corner-sharing octahedral tilt angles are 38°. There are two inequivalent Al sites. In the first Al site, Al(1) is bonded to two equivalent P(1) and two equivalent P(2) atoms to form distorted AlP4 tetrahedra that share corners with two equivalent Eu(2)P6 octahedra, corners with two equivalent Eu(3)P6 octahedra, edges with two equivalent Eu(3)P6 octahedra,  an edgeedge with one Al(1)P4 tetrahedra, and  an edgeedge with one Al(2)P4 tetrahedra. The corner-sharing octahedral tilt angles are 52°. In the second Al site, Al(2) is bonded to one P(3), one P(4), and two equivalent P(1) atoms to form AlP4 tetrahedra that share edges with two equivalent Eu(2)P6 octahedra, edges with two equivalent Eu(3)P6 octahedra, and  an edgeedge with one Al(1)P4 tetrahedra. There are five inequivalent P sites. In the first P site, P(1) is bonded in a 7-coordinate geometry to one Na(1), one Na(2), one Eu(1), one Eu(2), one Eu(3), one Al(1), and one Al(2) atom. In the second P site, P(2) is bonded in a 8-coordinate geometry to two equivalent Na(1), two equivalent Eu(1), two equivalent Eu(3), and two equivalent Al(1) atoms. In the third P site, P(3) is bonded in a 8-coordinate geometry to two equivalent Eu(2), four equivalent Eu(1), one Al(2), and one P(5) atom. In the fourth P site, P(4) is bonded in a 8-coordinate geometry to one Na(2), two equivalent Na(1), two equivalent Eu(1), two equivalent Eu(3), and one Al(2) atom. In the fifth P site, P(5) is bonded in a 8-coordinate geometry to one Na(2), two equivalent Eu(2), four equivalent Eu(1), and one P(3) atom.
NaEu2AlP3 crystallizes in the monoclinic C2/m space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded in a 2-coordinate geometry to two equivalent P(1), two equivalent P(2), and two equivalent P(4) atoms. Both Na(1)-P(1) bond lengths are 3.13 Å. Both Na(1)-P(2) bond lengths are 3.29 Å. Both Na(1)-P(4) bond lengths are 2.80 Å. In the second Na site, Na(2) is bonded in a 4-coordinate geometry to one P(4), one P(5), and two equivalent P(1) atoms. The Na(2)-P(4) bond length is 3.11 Å. The Na(2)-P(5) bond length is 3.14 Å. Both Na(2)-P(1) bond lengths are 2.66 Å. There are three inequivalent Eu sites. In the first Eu site, Eu(1) is bonded in a 7-coordinate geometry to one P(1), one P(2), one P(4), two equivalent P(3), and two equivalent P(5) atoms. The Eu(1)-P(1) bond length is 3.20 Å. The Eu(1)-P(2) bond length is 3.14 Å. The Eu(1)-P(4) bond length is 3.18 Å. There is one shorter (3.15 Å) and one longer (3.21 Å) Eu(1)-P(3) bond length. There is one shorter (3.18 Å) and one longer (3.23 Å) Eu(1)-P(5) bond length. In the second Eu site, Eu(2) is bonded to two equivalent P(1), two equivalent P(3), and two equivalent P(5) atoms to form EuP6 octahedra that share corners with two equivalent Eu(3)P6 octahedra, corners with two equivalent Al(1)P4 tetrahedra, edges with two equivalent Eu(2)P6 octahedra, and edges with two equivalent Al(2)P4 tetrahedra. The corner-sharing octahedral tilt angles are 38°. Both Eu(2)-P(1) bond lengths are 2.96 Å. Both Eu(2)-P(3) bond lengths are 3.13 Å. Both Eu(2)-P(5) bond lengths are 3.13 Å. In the third Eu site, Eu(3) is bonded to two equivalent P(1), two equivalent P(2), and two equivalent P(4) atoms to form distorted EuP6 octahedra that share corners with two equivalent Eu(2)P6 octahedra, corners with two equivalent Al(1)P4 tetrahedra, edges with two equivalent Eu(3)P6 octahedra, edges with two equivalent Al(1)P4 tetrahedra, and edges with two equivalent Al(2)P4 tetrahedra. The corner-sharing octahedral tilt angles are 38°. Both Eu(3)-P(1) bond lengths are 2.99 Å. Both Eu(3)-P(2) bond lengths are 3.07 Å. Both Eu(3)-P(4) bond lengths are 3.12 Å. There are two inequivalent Al sites. In the first Al site, Al(1) is bonded to two equivalent P(1) and two equivalent P(2) atoms to form distorted AlP4 tetrahedra that share corners with two equivalent Eu(2)P6 octahedra, corners with two equivalent Eu(3)P6 octahedra, edges with two equivalent Eu(3)P6 octahedra,  an edgeedge with one Al(1)P4 tetrahedra, and  an edgeedge with one Al(2)P4 tetrahedra. The corner-sharing octahedral tilt angles are 52°. Both Al(1)-P(1) bond lengths are 2.38 Å. There is one shorter (2.38 Å) and one longer (2.46 Å) Al(1)-P(2) bond length. In the second Al site, Al(2) is bonded to one P(3), one P(4), and two equivalent P(1) atoms to form AlP4 tetrahedra that share edges with two equivalent Eu(2)P6 octahedra, edges with two equivalent Eu(3)P6 octahedra, and  an edgeedge with one Al(1)P4 tetrahedra. The Al(2)-P(3) bond length is 2.46 Å. The Al(2)-P(4) bond length is 2.34 Å. Both Al(2)-P(1) bond lengths are 2.40 Å. There are five inequivalent P sites. In the first P site, P(1) is bonded in a 7-coordinate geometry to one Na(1), one Na(2), one Eu(1), one Eu(2), one Eu(3), one Al(1), and one Al(2) atom. In the second P site, P(2) is bonded in a 8-coordinate geometry to two equivalent Na(1), two equivalent Eu(1), two equivalent Eu(3), and two equivalent Al(1) atoms. In the third P site, P(3) is bonded in a 8-coordinate geometry to two equivalent Eu(2), four equivalent Eu(1), one Al(2), and one P(5) atom. The P(3)-P(5) bond length is 2.32 Å. In the fourth P site, P(4) is bonded in a 8-coordinate geometry to one Na(2), two equivalent Na(1), two equivalent Eu(1), two equivalent Eu(3), and one Al(2) atom. In the fifth P site, P(5) is bonded in a 8-coordinate geometry to one Na(2), two equivalent Eu(2), four equivalent Eu(1), and one P(3) atom.