Cuprous
Cuprous refers to copper in the +1 oxidation state, denoted Cu+. The term is used to distinguish compounds and ions containing copper in this oxidation state from cupric, which denotes Cu2+. In cuprous compounds copper often exhibits a d10 configuration, which influences geometry and color, with many Cu+ salts being colorless or white. Cuprous oxide, Cu2O, is a notable exception as a red solid.
Common cuprous salts include copper(I) chloride (CuCl), copper(I) bromide (CuBr), and copper(I) iodide (CuI). Cu2O occurs
In aqueous solution, Cu+ is relatively unstable: it is readily oxidized to Cu2+ in the presence of
Cuprous compounds are discussed in contrast to copper in the +2 oxidation state, cupric. The term derives