Na5SrTaP4 is alpha Pu-derived structured and crystallizes in the monoclinic Cc space group. There are five inequivalent Na sites. In the first Na site, Na(1) is bonded in a 6-coordinate geometry to one Ta(1), one P(4), two equivalent P(2), and two equivalent P(3) atoms. In the second Na site, Na(2) is bonded in a 3-coordinate geometry to one P(2), one P(3), one P(4), and two equivalent P(1) atoms. In the third Na site, Na(3) is bonded in a 4-coordinate geometry to one P(1), one P(2), one P(3), and one P(4) atom. In the fourth Na site, Na(4) is bonded in a 4-coordinate geometry to one P(1), one P(4), and two equivalent P(3) atoms. In the fifth Na site, Na(5) is bonded to one P(1), one P(4), and two equivalent P(2) atoms to form distorted NaP4 trigonal pyramids that share corners with two equivalent Ta(1)NaP4 tetrahedra, corners with two equivalent Na(5)P4 trigonal pyramids, and  an edgeedge with one Ta(1)NaP4 tetrahedra. Sr(1) is bonded in a 5-coordinate geometry to one P(2), one P(3), one P(4), and two equivalent P(1) atoms. Ta(1) is bonded to one Na(1), one P(1), one P(2), one P(3), and one P(4) atom to form TaNaP4 tetrahedra that share corners with two equivalent Na(5)P4 trigonal pyramids and  an edgeedge with one Na(5)P4 trigonal pyramid. There are four inequivalent P sites. In the first P site, P(4) is bonded in a 7-coordinate geometry to one Na(1), one Na(2), one Na(3), one Na(4), one Na(5), one Sr(1), and one Ta(1) atom. In the second P site, P(1) is bonded in a 8-coordinate geometry to one Na(3), one Na(4), one Na(5), two equivalent Na(2), two equivalent Sr(1), and one Ta(1) atom. In the third P site, P(2) is bonded in a 8-coordinate geometry to one Na(2), one Na(3), two equivalent Na(1), two equivalent Na(5), one Sr(1), and one Ta(1) atom. In the fourth P site, P(3) is bonded in a 8-coordinate geometry to one Na(2), one Na(3), two equivalent Na(1), two equivalent Na(4), one Sr(1), and one Ta(1) atom.
Na5SrTaP4 is alpha Pu-derived structured and crystallizes in the monoclinic Cc space group. There are five inequivalent Na sites. In the first Na site, Na(1) is bonded in a 6-coordinate geometry to one Ta(1), one P(4), two equivalent P(2), and two equivalent P(3) atoms. The Na(1)-Ta(1) bond length is 3.28 Å. The Na(1)-P(4) bond length is 3.02 Å. There is one shorter (3.07 Å) and one longer (3.32 Å) Na(1)-P(2) bond length. There is one shorter (3.05 Å) and one longer (3.22 Å) Na(1)-P(3) bond length. In the second Na site, Na(2) is bonded in a 3-coordinate geometry to one P(2), one P(3), one P(4), and two equivalent P(1) atoms. The Na(2)-P(2) bond length is 3.30 Å. The Na(2)-P(3) bond length is 3.04 Å. The Na(2)-P(4) bond length is 2.98 Å. There is one shorter (3.06 Å) and one longer (3.25 Å) Na(2)-P(1) bond length. In the third Na site, Na(3) is bonded in a 4-coordinate geometry to one P(1), one P(2), one P(3), and one P(4) atom. The Na(3)-P(1) bond length is 2.94 Å. The Na(3)-P(2) bond length is 2.92 Å. The Na(3)-P(3) bond length is 2.87 Å. The Na(3)-P(4) bond length is 3.10 Å. In the fourth Na site, Na(4) is bonded in a 4-coordinate geometry to one P(1), one P(4), and two equivalent P(3) atoms. The Na(4)-P(1) bond length is 2.97 Å. The Na(4)-P(4) bond length is 3.03 Å. There is one shorter (2.84 Å) and one longer (2.98 Å) Na(4)-P(3) bond length. In the fifth Na site, Na(5) is bonded to one P(1), one P(4), and two equivalent P(2) atoms to form distorted NaP4 trigonal pyramids that share corners with two equivalent Ta(1)NaP4 tetrahedra, corners with two equivalent Na(5)P4 trigonal pyramids, and  an edgeedge with one Ta(1)NaP4 tetrahedra. The Na(5)-P(1) bond length is 2.97 Å. The Na(5)-P(4) bond length is 3.09 Å. There is one shorter (2.88 Å) and one longer (2.90 Å) Na(5)-P(2) bond length. Sr(1) is bonded in a 5-coordinate geometry to one P(2), one P(3), one P(4), and two equivalent P(1) atoms. The Sr(1)-P(2) bond length is 3.06 Å. The Sr(1)-P(3) bond length is 3.19 Å. The Sr(1)-P(4) bond length is 3.01 Å. There is one shorter (3.07 Å) and one longer (3.23 Å) Sr(1)-P(1) bond length. Ta(1) is bonded to one Na(1), one P(1), one P(2), one P(3), and one P(4) atom to form TaNaP4 tetrahedra that share corners with two equivalent Na(5)P4 trigonal pyramids and  an edgeedge with one Na(5)P4 trigonal pyramid. The Ta(1)-P(1) bond length is 2.41 Å. The Ta(1)-P(2) bond length is 2.37 Å. The Ta(1)-P(3) bond length is 2.39 Å. The Ta(1)-P(4) bond length is 2.38 Å. There are four inequivalent P sites. In the first P site, P(4) is bonded in a 7-coordinate geometry to one Na(1), one Na(2), one Na(3), one Na(4), one Na(5), one Sr(1), and one Ta(1) atom. In the second P site, P(1) is bonded in a 8-coordinate geometry to one Na(3), one Na(4), one Na(5), two equivalent Na(2), two equivalent Sr(1), and one Ta(1) atom. In the third P site, P(2) is bonded in a 8-coordinate geometry to one Na(2), one Na(3), two equivalent Na(1), two equivalent Na(5), one Sr(1), and one Ta(1) atom. In the fourth P site, P(3) is bonded in a 8-coordinate geometry to one Na(2), one Na(3), two equivalent Na(1), two equivalent Na(4), one Sr(1), and one Ta(1) atom.