Iron(II) compounds, also known as ferrous compounds, contain iron in the +2 oxidation state. They are commonly found in nature and play a crucial role in various biological processes. Examples include ferrous sulfate and ferrous chloride, which are often used in agriculture and water treatment. These compounds are typically characterized by their greenish color and are soluble in water. Iron(II) compounds can easily oxidize to Iron(III) compounds, which are in the +3 oxidation state. This property makes them important in both industrial applications and environmental chemistry.