Na5As4 crystallizes in the monoclinic C2/m space group. There are three inequivalent Na sites. In the first Na site, Na(1) is bonded in a 7-coordinate geometry to two equivalent As(1) and five equivalent As(2) atoms. In the second Na site, Na(2) is bonded in a 6-coordinate geometry to two equivalent As(2) and four equivalent As(1) atoms. In the third Na site, Na(3) is bonded in a distorted square co-planar geometry to four equivalent As(1) atoms. There are two inequivalent As sites. In the first As site, As(1) is bonded in a 9-coordinate geometry to two equivalent Na(1), two equivalent Na(3), four equivalent Na(2), and one As(2) atom. In the second As site, As(2) is bonded in a 9-coordinate geometry to two equivalent Na(2), five equivalent Na(1), one As(1), and one As(2) atom.
Na5As4 crystallizes in the monoclinic C2/m space group. There are three inequivalent Na sites. In the first Na site, Na(1) is bonded in a 7-coordinate geometry to two equivalent As(1) and five equivalent As(2) atoms. Both Na(1)-As(1) bond lengths are 3.10 Å. There are a spread of Na(1)-As(2) bond distances ranging from 3.03-3.16 Å. In the second Na site, Na(2) is bonded in a 6-coordinate geometry to two equivalent As(2) and four equivalent As(1) atoms. Both Na(2)-As(2) bond lengths are 3.15 Å. There are a spread of Na(2)-As(1) bond distances ranging from 3.09-3.21 Å. In the third Na site, Na(3) is bonded in a distorted square co-planar geometry to four equivalent As(1) atoms. All Na(3)-As(1) bond lengths are 2.95 Å. There are two inequivalent As sites. In the first As site, As(1) is bonded in a 9-coordinate geometry to two equivalent Na(1), two equivalent Na(3), four equivalent Na(2), and one As(2) atom. The As(1)-As(2) bond length is 2.42 Å. In the second As site, As(2) is bonded in a 9-coordinate geometry to two equivalent Na(2), five equivalent Na(1), one As(1), and one As(2) atom. The As(2)-As(2) bond length is 2.45 Å.