Copper sulfate, also known as cuprous sulfate and dicopper sulfate, is the chemical compound with the chemical formulaCu2SO4 and a molar mass of 223.15 g mol−1. It is an unstable compound as copper compounds are generally unstable and is more commonly found in the CuSO4 state. It is white in color at room temperature and is water-soluble. Due to the low-stability of the compound there are currently not many applications to date.
Synthesis
Anhydrous Cu2SO4, can be synthesized at approximately around 75% purity by the action of dimethyl sulfate on Cu2O following the formula: The material is fairly stable in dry air at room temperature but decomposes rapidly in presence of moisture or on heating. Due to its instability the material starts to decompose when heated or if water is present to CuSO4 and follows the formula: Around temperatures of 300 °C it is not likely for any Cu2SO4 to be present as the structure is just not stable enough. It can also be prepared by reducing copper sulfate solution with a reducing agent like solution sodium bisulfite or sodium thiosulfate to reduce Cu2+ to Cu+. This is visibly noticeable as the blue CuSO4 will begin to turn colorless when the cuprous ion is formed.
Structure
Cu2SO4 crystallizes in the orthorhombic space group Fddd with cubic closest pack cell unit properties a = 474.8, b = 1396, and c = 1086 pm, Z = 8, Dx = 4.12 g cm−3. The structure is formed by the tendency of Cu to form two collinear sp bonds to oxygen atoms which result in short O-Cu-O groups with the O-Cu bond length being approximately 196vpm. Due to the bonding properties of the Cu metal the structure is built of layers of composition Cu2SO4. Due to the loss of only one electron and the bonding properties of copper the structure is built up from four oxygen atoms of each sulfate group bonding to four other sulfate groups of the same layer via symmetrical O-Cu-O bridging. Due to its unstable nature it is difficult to obtain an accurate 3D structure, but was first successfully done in 1987 by Berthold, Born, and Wartchow.
Applications
No current common uses due to stability issues. However, its more common copper sulfate form has various current uses from production of fungicides and insecticides, growth stimulation in agriculture, soil sterilization, disinfection, preservatives, antiseptics, pharmaceuticals, disease prevention, mold protection, gas purification and coloring, textiles, public health and medicine, agriculture, and chemistry.
