The Collaborative International Dictionary
Diiodide
Diiodide \Di*i"o*dide\ (?; 104), n. [Pref. di- + iodine.] (Chem.) A compound of a binary type containing two atoms of iodine; -- called also biniodide.
Wiktionary
diiodide
n. (context chemistry English) any iodide containing two iodine atoms in each molecule