Copper(II) sulfate octahydrate, often represented as CuSO4·8H2O, is a blue crystalline compound commonly used in laboratories and agriculture. It consists of one copper ion, one sulfate ion, and eight water molecules, which contribute to its vibrant color and solubility in water. This compound is frequently utilized as a fungicide, herbicide, and pesticide in farming, helping to control various plant diseases. Additionally, it serves as a reagent in chemical reactions and is used in the preparation of other copper compounds.