Although a common name for the compound is selenium monochloride, reflecting its empirical formula, IUPAC does not recommend that name, instead preferring the more descriptive diselenium dichloride.

With a nonplanar structure, it has C2 molecular symmetry, similar to hydrogen peroxide and disulfur dichloride, which is referred to as gauche.

[2] Early routes to diselenium dichloride involved chlorination of elemental selenium.

A second method for the synthesis involves the reaction of selenium with oleum and hydrochloric acid:[4] The crude diselenium dichloride is removed via separatory funnel.

[7] Finally, the compound has been used to introduce bridging selenium ligands between the metal atoms of some iron and chromium carbonyl complexes.