CHEMICAL NATURE OF THE URANIUM SELENIDE U$sub 3$Se$sub 5$

The reactions of the selenide U/sub 3/Se/sub 5/ with silver nitrate were analyzed. The principal reaction is very fast and yields only solids. Extended reaction periods produce the gas NO, a solid (which is a mixture of silver selenide, selenium, and silver), and the filtrate containing all the uranium in the form of uranyl salts. The formulas describing these reactions are given. This selenide assures a transition between the ionic uranium selenide and the covalent uranium selenide. The selenide U/sub 3/Se/sub 5/ represents an equimolecular combination of the selenides USe/sub 2/ and U/sub 2/Se/sub 3/. (J.S.R.)