Bis(1-ethyl-3-methyl-imidazolium) 3,6-diselanyl-idene-1,2,4,5-tetra-selena-3,6-diphospha-cyclo-hexane-3,6-di-selen-olate.

In the title compound, 2C6H11N2 (+)·P2Se8 (2-) or [EMIM]2P2Se8 (EMIM = 1-ethyl-3-methyl-imidazolium), the anions, located about inversion centers between EMIM cations, exhibit a cyclo-hexane-like chair conformation. The cations are found in columns along the a axis, with centroid-centroid distances of 3.8399 (3) and 4.7530 (2) Å. The observed P-Se distances and Se-P-Se angles agree with other salts of this anion.