Na5AuSe12 crystallizes in the monoclinic P2_1 space group. There are five inequivalent Na sites. In the first Na site, Na(1) is bonded to one Se(1), one Se(11), one Se(12), one Se(2), one Se(5), and one Se(8) atom to form a mixture of distorted corner and edge-sharing NaSe6 square pyramids. In the second Na site, Na(2) is bonded to one Se(11), one Se(12), one Se(2), one Se(4), and one Se(5) atom to form distorted NaSe5 trigonal bipyramids that share corners with two equivalent Na(1)Se6 square pyramids,  an edgeedge with one Na(4)Se5 square pyramid, and  an edgeedge with one Na(1)Se6 square pyramid. In the third Na site, Na(3) is bonded in a 5-coordinate geometry to one Se(12), one Se(2), one Se(4), one Se(8), and one Se(9) atom. In the fourth Na site, Na(4) is bonded to one Se(1), one Se(11), one Se(12), one Se(3), and one Se(8) atom to form NaSe5 square pyramids that share corners with two equivalent Na(1)Se6 square pyramids,  an edgeedge with one Na(1)Se6 square pyramid, and  an edgeedge with one Na(2)Se5 trigonal bipyramid. In the fifth Na site, Na(5) is bonded in a 5-coordinate geometry to one Se(10), one Se(11), one Se(2), one Se(3), one Se(4), and one Se(8) atom. Au(1) is bonded in a rectangular see-saw-like geometry to one Se(1), one Se(3), one Se(4), and one Se(5) atom. There are twelve inequivalent Se sites. In the first Se site, Se(12) is bonded to one Na(1), one Na(2), one Na(3), one Na(4), and one Se(6) atom to form a mixture of distorted corner and edge-sharing SeNa4Se square pyramids. In the second Se site, Se(1) is bonded in a 4-coordinate geometry to one Na(1), one Na(4), one Au(1), and one Se(9) atom. In the third Se site, Se(2) is bonded in a 5-coordinate geometry to one Na(1), one Na(2), one Na(3), one Na(5), and one Se(10) atom. In the fourth Se site, Se(3) is bonded in a distorted see-saw-like geometry to one Na(4), one Na(5), one Au(1), and one Se(7) atom. In the fifth Se site, Se(4) is bonded in a 5-coordinate geometry to one Na(2), one Na(3), one Na(5), one Au(1), and one Se(6) atom. In the sixth Se site, Se(5) is bonded in a 4-coordinate geometry to one Na(1), one Na(2), one Au(1), and one Se(10) atom. In the seventh Se site, Se(6) is bonded in a water-like geometry to one Se(12) and one Se(4) atom. In the eighth Se site, Se(7) is bonded in a water-like geometry to one Se(11) and one Se(3) atom. In the ninth Se site, Se(8) is bonded to one Na(1), one Na(3), one Na(4), one Na(5), and one Se(9) atom to form a mixture of distorted corner and edge-sharing SeNa4Se trigonal bipyramids. In the tenth Se site, Se(9) is bonded in a distorted T-shaped geometry to one Na(3), one Se(1), and one Se(8) atom. In the eleventh Se site, Se(10) is bonded in a 3-coordinate geometry to one Na(5), one Se(2), and one Se(5) atom. In the twelfth Se site, Se(11) is bonded in a 5-coordinate geometry to one Na(1), one Na(2), one Na(4), one Na(5), and one Se(7) atom.
Na5AuSe12 crystallizes in the monoclinic P2_1 space group. There are five inequivalent Na sites. In the first Na site, Na(1) is bonded to one Se(1), one Se(11), one Se(12), one Se(2), one Se(5), and one Se(8) atom to form a mixture of distorted corner and edge-sharing NaSe6 square pyramids. The Na(1)-Se(1) bond length is 2.98 Å. The Na(1)-Se(11) bond length is 3.02 Å. The Na(1)-Se(12) bond length is 3.01 Å. The Na(1)-Se(2) bond length is 3.57 Å. The Na(1)-Se(5) bond length is 3.00 Å. The Na(1)-Se(8) bond length is 3.03 Å. In the second Na site, Na(2) is bonded to one Se(11), one Se(12), one Se(2), one Se(4), and one Se(5) atom to form distorted NaSe5 trigonal bipyramids that share corners with two equivalent Na(1)Se6 square pyramids,  an edgeedge with one Na(4)Se5 square pyramid, and  an edgeedge with one Na(1)Se6 square pyramid. The Na(2)-Se(11) bond length is 2.85 Å. The Na(2)-Se(12) bond length is 2.95 Å. The Na(2)-Se(2) bond length is 2.94 Å. The Na(2)-Se(4) bond length is 3.18 Å. The Na(2)-Se(5) bond length is 3.04 Å. In the third Na site, Na(3) is bonded in a 5-coordinate geometry to one Se(12), one Se(2), one Se(4), one Se(8), and one Se(9) atom. The Na(3)-Se(12) bond length is 2.92 Å. The Na(3)-Se(2) bond length is 2.96 Å. The Na(3)-Se(4) bond length is 3.09 Å. The Na(3)-Se(8) bond length is 2.96 Å. The Na(3)-Se(9) bond length is 3.38 Å. In the fourth Na site, Na(4) is bonded to one Se(1), one Se(11), one Se(12), one Se(3), and one Se(8) atom to form NaSe5 square pyramids that share corners with two equivalent Na(1)Se6 square pyramids,  an edgeedge with one Na(1)Se6 square pyramid, and  an edgeedge with one Na(2)Se5 trigonal bipyramid. The Na(4)-Se(1) bond length is 3.05 Å. The Na(4)-Se(11) bond length is 2.96 Å. The Na(4)-Se(12) bond length is 3.02 Å. The Na(4)-Se(3) bond length is 3.06 Å. The Na(4)-Se(8) bond length is 2.92 Å. In the fifth Na site, Na(5) is bonded in a 5-coordinate geometry to one Se(10), one Se(11), one Se(2), one Se(3), one Se(4), and one Se(8) atom. The Na(5)-Se(10) bond length is 3.46 Å. The Na(5)-Se(11) bond length is 2.83 Å. The Na(5)-Se(2) bond length is 3.00 Å. The Na(5)-Se(3) bond length is 3.12 Å. The Na(5)-Se(4) bond length is 3.28 Å. The Na(5)-Se(8) bond length is 2.95 Å. Au(1) is bonded in a rectangular see-saw-like geometry to one Se(1), one Se(3), one Se(4), and one Se(5) atom. The Au(1)-Se(1) bond length is 2.53 Å. The Au(1)-Se(3) bond length is 2.52 Å. The Au(1)-Se(4) bond length is 2.54 Å. The Au(1)-Se(5) bond length is 2.52 Å. There are twelve inequivalent Se sites. In the first Se site, Se(12) is bonded to one Na(1), one Na(2), one Na(3), one Na(4), and one Se(6) atom to form a mixture of distorted corner and edge-sharing SeNa4Se square pyramids. The Se(12)-Se(6) bond length is 2.37 Å. In the second Se site, Se(1) is bonded in a 4-coordinate geometry to one Na(1), one Na(4), one Au(1), and one Se(9) atom. The Se(1)-Se(9) bond length is 2.38 Å. In the third Se site, Se(2) is bonded in a 5-coordinate geometry to one Na(1), one Na(2), one Na(3), one Na(5), and one Se(10) atom. The Se(2)-Se(10) bond length is 2.36 Å. In the fourth Se site, Se(3) is bonded in a distorted see-saw-like geometry to one Na(4), one Na(5), one Au(1), and one Se(7) atom. The Se(3)-Se(7) bond length is 2.36 Å. In the fifth Se site, Se(4) is bonded in a 5-coordinate geometry to one Na(2), one Na(3), one Na(5), one Au(1), and one Se(6) atom. The Se(4)-Se(6) bond length is 2.36 Å. In the sixth Se site, Se(5) is bonded in a 4-coordinate geometry to one Na(1), one Na(2), one Au(1), and one Se(10) atom. The Se(5)-Se(10) bond length is 2.36 Å. In the seventh Se site, Se(6) is bonded in a water-like geometry to one Se(12) and one Se(4) atom. In the eighth Se site, Se(7) is bonded in a water-like geometry to one Se(11) and one Se(3) atom. The Se(7)-Se(11) bond length is 2.37 Å. In the ninth Se site, Se(8) is bonded to one Na(1), one Na(3), one Na(4), one Na(5), and one Se(9) atom to form a mixture of distorted corner and edge-sharing SeNa4Se trigonal bipyramids. The Se(8)-Se(9) bond length is 2.37 Å. In the tenth Se site, Se(9) is bonded in a distorted T-shaped geometry to one Na(3), one Se(1), and one Se(8) atom. In the eleventh Se site, Se(10) is bonded in a 3-coordinate geometry to one Na(5), one Se(2), and one Se(5) atom. In the twelfth Se site, Se(11) is bonded in a 5-coordinate geometry to one Na(1), one Na(2), one Na(4), one Na(5), and one Se(7) atom.