Copper ii sulfate pentahydrate is a blue crystalline solid that combines with water to form copper sulfate, which has a melting point of 110 degC. It is used as a base in Bordeaux mixtures and fungicides. It is a moderately toxic metal salt that can be dangerous for small children and pets to ingest or inhale.
Soluble in water, methanol and glycerol; slightly soluble in ethanol. Structurally it contains four copper(II) ions surrounded by three water molecules in the corners and a fifth attached to the water molecule via hydrogen bonding. It has a nauseating metallic taste, and is non-combustible.
Density: 31.6 g/L at 0@C and 203.3 g/L at 100@C.
The anhydrous form is white and odorless; the hydrated form turns blue when heated. It is often used in school chemistry sets and undergraduate experiments.
In agriculture, it is used to control algae in water supplies and is also an effective tadpole shrimp destroyer on flooded rice fields. It is also used to adjust and maintain copper-deficient soils. It can be used in waste treatment to kill roots in landfills and to treat sewer sludge.
There is little evidence that copper sulfate biomagnifies from plants to animals in the environment. This is a common finding with heavy metals, and does not suggest that this particular compound is harmful to marine life or the environment.
Ecotoxicity: Fish, rainbow trout and bluegill/sunfish have LC50 values of 0.1-2.5 mg/L at 96 hours (in a solution of 0.5 mL/gallon). This concentration is essentially neutral with regard to fish sensitivity to copper salts.