NaSr2AlP3 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(5) atoms. In the second Na site, Na(2) is bonded in a distorted T-shaped geometry to one P(2) and two equivalent P(1) atoms. There are three inequivalent Sr sites. In the first Sr site, Sr(1) is bonded in a 8-coordinate geometry to one Al(1), one P(1), one P(2), one P(5), two equivalent P(3), and two equivalent P(4) atoms. In the second Sr site, Sr(2) is bonded to two equivalent P(1), two equivalent P(3), and two equivalent P(4) atoms to form SrP6 octahedra that share corners with two equivalent Sr(3)P6 octahedra, corners with two equivalent Al(2)P4 tetrahedra, edges with two equivalent Sr(2)P6 octahedra, and edges with two equivalent Al(1)Sr2P4 tetrahedra. The corner-sharing octahedral tilt angles are 37°. In the third Sr site, Sr(3) is bonded to two equivalent P(1), two equivalent P(2), and two equivalent P(5) atoms to form distorted SrP6 octahedra that share corners with two equivalent Sr(2)P6 octahedra, corners with two equivalent Al(2)P4 tetrahedra, edges with two equivalent Sr(3)P6 octahedra, edges with two equivalent Al(2)P4 tetrahedra, and edges with two equivalent Al(1)Sr2P4 tetrahedra. The corner-sharing octahedral tilt angles are 37°. There are two inequivalent Al sites. In the first Al site, Al(1) is bonded to two equivalent Sr(1), one P(2), one P(4), and two equivalent P(1) atoms to form distorted AlSr2P4 tetrahedra that share edges with two equivalent Sr(2)P6 octahedra, edges with two equivalent Sr(3)P6 octahedra, and  an edgeedge with one Al(2)P4 tetrahedra. In the second Al site, Al(2) is bonded to two equivalent P(1) and two equivalent P(5) atoms to form distorted AlP4 tetrahedra that share corners with two equivalent Sr(2)P6 octahedra, corners with two equivalent Sr(3)P6 octahedra, edges with two equivalent Sr(3)P6 octahedra,  an edgeedge with one Al(2)P4 tetrahedra, and  an edgeedge with one Al(1)Sr2P4 tetrahedra. The corner-sharing octahedral tilt angles range from 51-52°. 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 Sr(1), one Sr(2), one Sr(3), one Al(1), and one Al(2) atom. In the second P site, P(2) is bonded in a 8-coordinate geometry to one Na(2), two equivalent Na(1), two equivalent Sr(1), two equivalent Sr(3), and one Al(1) atom. In the third P site, P(3) is bonded in a 7-coordinate geometry to two equivalent Sr(2), four equivalent Sr(1), and one P(3) atom. In the fourth P site, P(4) is bonded in a 8-coordinate geometry to two equivalent Sr(2), four equivalent Sr(1), one Al(1), and one P(4) atom. In the fifth P site, P(5) is bonded in a 8-coordinate geometry to two equivalent Na(1), two equivalent Sr(1), two equivalent Sr(3), and two equivalent Al(2) atoms.
NaSr2AlP3 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(5) atoms. Both Na(1)-P(1) bond lengths are 3.18 Å. Both Na(1)-P(2) bond lengths are 2.90 Å. Both Na(1)-P(5) bond lengths are 3.31 Å. In the second Na site, Na(2) is bonded in a distorted T-shaped geometry to one P(2) and two equivalent P(1) atoms. The Na(2)-P(2) bond length is 3.02 Å. Both Na(2)-P(1) bond lengths are 2.75 Å. There are three inequivalent Sr sites. In the first Sr site, Sr(1) is bonded in a 8-coordinate geometry to one Al(1), one P(1), one P(2), one P(5), two equivalent P(3), and two equivalent P(4) atoms. The Sr(1)-Al(1) bond length is 3.34 Å. The Sr(1)-P(1) bond length is 3.30 Å. The Sr(1)-P(2) bond length is 3.21 Å. The Sr(1)-P(5) bond length is 3.16 Å. There is one shorter (3.09 Å) and one longer (3.13 Å) Sr(1)-P(3) bond length. There is one shorter (3.45 Å) and one longer (3.47 Å) Sr(1)-P(4) bond length. In the second Sr site, Sr(2) is bonded to two equivalent P(1), two equivalent P(3), and two equivalent P(4) atoms to form SrP6 octahedra that share corners with two equivalent Sr(3)P6 octahedra, corners with two equivalent Al(2)P4 tetrahedra, edges with two equivalent Sr(2)P6 octahedra, and edges with two equivalent Al(1)Sr2P4 tetrahedra. The corner-sharing octahedral tilt angles are 37°. Both Sr(2)-P(1) bond lengths are 3.04 Å. Both Sr(2)-P(3) bond lengths are 3.20 Å. Both Sr(2)-P(4) bond lengths are 3.20 Å. In the third Sr site, Sr(3) is bonded to two equivalent P(1), two equivalent P(2), and two equivalent P(5) atoms to form distorted SrP6 octahedra that share corners with two equivalent Sr(2)P6 octahedra, corners with two equivalent Al(2)P4 tetrahedra, edges with two equivalent Sr(3)P6 octahedra, edges with two equivalent Al(2)P4 tetrahedra, and edges with two equivalent Al(1)Sr2P4 tetrahedra. The corner-sharing octahedral tilt angles are 37°. Both Sr(3)-P(1) bond lengths are 3.06 Å. Both Sr(3)-P(2) bond lengths are 3.21 Å. Both Sr(3)-P(5) bond lengths are 3.11 Å. There are two inequivalent Al sites. In the first Al site, Al(1) is bonded to two equivalent Sr(1), one P(2), one P(4), and two equivalent P(1) atoms to form distorted AlSr2P4 tetrahedra that share edges with two equivalent Sr(2)P6 octahedra, edges with two equivalent Sr(3)P6 octahedra, and  an edgeedge with one Al(2)P4 tetrahedra. The Al(1)-P(2) bond length is 2.37 Å. The Al(1)-P(4) bond length is 2.56 Å. Both Al(1)-P(1) bond lengths are 2.41 Å. In the second Al site, Al(2) is bonded to two equivalent P(1) and two equivalent P(5) atoms to form distorted AlP4 tetrahedra that share corners with two equivalent Sr(2)P6 octahedra, corners with two equivalent Sr(3)P6 octahedra, edges with two equivalent Sr(3)P6 octahedra,  an edgeedge with one Al(2)P4 tetrahedra, and  an edgeedge with one Al(1)Sr2P4 tetrahedra. The corner-sharing octahedral tilt angles range from 51-52°. Both Al(2)-P(1) bond lengths are 2.39 Å. There is one shorter (2.37 Å) and one longer (2.45 Å) Al(2)-P(5) bond length. 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 Sr(1), one Sr(2), one Sr(3), one Al(1), and one Al(2) atom. In the second P site, P(2) is bonded in a 8-coordinate geometry to one Na(2), two equivalent Na(1), two equivalent Sr(1), two equivalent Sr(3), and one Al(1) atom. In the third P site, P(3) is bonded in a 7-coordinate geometry to two equivalent Sr(2), four equivalent Sr(1), and one P(3) atom. The P(3)-P(3) bond length is 2.28 Å. In the fourth P site, P(4) is bonded in a 8-coordinate geometry to two equivalent Sr(2), four equivalent Sr(1), one Al(1), and one P(4) atom. The P(4)-P(4) bond length is 2.27 Å. In the fifth P site, P(5) is bonded in a 8-coordinate geometry to two equivalent Na(1), two equivalent Sr(1), two equivalent Sr(3), and two equivalent Al(2) atoms.