Copper(II) sulfate, also known as cupric sulfate or copper sulphate, is the chemical compound with the chemical formula CuSO4. This salt exists as a series of compounds that differ in their degree of hydration. The anhydrous form is a pale green or gray-white powder, whereas the pentahydrate (CuSO4·5H2O), the most commonly encountered salt, is bright blue. CuSO4 · 5H2O is in a shade of blue, and very toxic to the environment, irritating to the eyes and skin, and also can be harmful if swallowed. Copper(II) sulfate exothermically dissolves in water to give the aquo complex [Cu(H2O)6]2+, which has octahedral molecular geometry and is paramagnetic. Other names for copper(II) sulfate are “blue vitriol” and “bluestone”.
Many commercial producers powder their copper sulfate before sale, making it easier to handle and to mix with other materials to create desired chemical compounds. As a general rule, copper sulfate is highly soluble, dissolving readily in a wide range of materials.
Today in the world there are more than 100 manufacturers and the world’s consumption is around 200,000 tonnes per annum. It is estimated that approximately three-quarters of this is used in agriculture, principally as a fungicide, but also for treating copper-deficient soils.
In pyrotechnics, copper sulfate is used to create striking blue fireworks. It is also used in agriculture as a treatment for crops and water systems, as it is a fungicide, herbicide, and pesticide. This compound is commonly sprayed on grapes in the form of a water solution to reduce the risk of fungal infestations. Copper sulfate is also used to treat leather, to make germicides, and in electroplating processes. It has also been historically used to dye textiles.
Copper sulfate is a fungicide used to control bacterial and fungal diseases of fruit, vegetable, nut and field crops. Some of the diseases that are controlled by this fungicide include mildew, leaf spots, blights and apple scab. It is used in combination with lime and water as a protective fungicide, referred to as Bordeaux mixture, for leaf application and seed treatment. It is also used as an algaecide, an herbicide in irrigation and municipal water treatment systems, and as a molluscicide, a material used to repel and kill slugs and snails. Copper sulfate is a naturally-occurring inorganic salt and copper is an essential trace element in plant and animal nutrition .It is available in the following formulations: dusts, wettable powders, and fluid concentrates
Several chemical tests utilize copper sulfate. It is used in Fehling’s solution and Benedict’s solution to test for reducing sugars, which reduce the soluble blue copper(II) sulfate to insoluble red copper(I) oxide. Copper(II) sulfate is also used in the Biuret reagent to test for proteins.
Copper sulfate is also used to test blood for anemia. The blood is tested by dropping it into a solution of copper sulfate of known specific gravity – blood which contains sufficient hemoglobin sinks rapidly due to its density, whereas blood which does not floats or sinks less rapidly.
In a flame test, its copper ions emit a deep green light, a much deeper green than the flame test for barium.
In the presence of chlorine, copper ions emit a deep blue light.