NaSe2 crystallizes in the tetragonal I-42d space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded in a 6-coordinate geometry to two equivalent Se(1) and four equivalent Se(2) atoms. In the second Na site, Na(2) is bonded in a 6-coordinate geometry to two equivalent Se(1) and four equivalent Se(2) atoms. There are two inequivalent Se sites. In the first Se site, Se(1) is bonded in a distorted see-saw-like geometry to one Na(1), one Na(2), one Se(1), and one Se(2) atom. In the second Se site, Se(2) is bonded in a 5-coordinate geometry to two equivalent Na(1), two equivalent Na(2), and one Se(1) atom.
NaSe2 crystallizes in the tetragonal I-42d space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded in a 6-coordinate geometry to two equivalent Se(1) and four equivalent Se(2) atoms. Both Na(1)-Se(1) bond lengths are 3.12 Å. There are two shorter (2.92 Å) and two longer (3.10 Å) Na(1)-Se(2) bond lengths. In the second Na site, Na(2) is bonded in a 6-coordinate geometry to two equivalent Se(1) and four equivalent Se(2) atoms. Both Na(2)-Se(1) bond lengths are 3.17 Å. There are two shorter (2.96 Å) and two longer (3.07 Å) Na(2)-Se(2) bond lengths. There are two inequivalent Se sites. In the first Se site, Se(1) is bonded in a distorted see-saw-like geometry to one Na(1), one Na(2), one Se(1), and one Se(2) atom. The Se(1)-Se(1) bond length is 2.37 Å. The Se(1)-Se(2) bond length is 2.38 Å. In the second Se site, Se(2) is bonded in a 5-coordinate geometry to two equivalent Na(1), two equivalent Na(2), and one Se(1) atom.