Ferrous

In chemistry, iron(II) refers to the elementiron in its +2 oxidation state. The adjective ferrous or the prefix ferro- is often used to specify such compounds, as in ferrous chloride for iron(II) chloride (FeCl₂). The adjective ferric is used instead for iron(III) salts, containing the cation Fe. The word is derived from the Latin word , meaning "iron".

In ionic compounds (salts), such an atom may occur as a separate cation (positive ion) abbreviated as Fe, although more precise descriptions include other ligands such as water and halides. Iron(II) centres occur in coordination complexes, such as in the anionferrocyanide, [Fe(CN)₆], where six cyanide ligands are bound the metal centre; or, in organometallic compounds, such as the ferrocene[Fe(C₅H₅)₂], where two cyclopentadienyl anions are bound to the Fe centre.