<unk> (II) sulfate (British English:<unk> (II) sulphate) or<unk> rrous sulfate denotes a range of salts with the formula<unk> SO4·xH2O. These compounds exist most commonly as the heptahydrate (x = 7) but several values for x are known. The hydrated form is used medically to treat<unk>  deficiency, and also for industrial applications. Known since ancient times as copperas and as green vitriol (vitriol is an archaic name for sulfate), the blue-green heptahydrate (hydrate with 7 molecules of water) is the most common form of this material. All the<unk> (II) sulfates dissolve in water to give the same aquo complex<unk> (H2O)62+, which has octahedral molecular geometry and is paramagnetic. The name copperas dates from times when the copper(II) sulfate was known as blue copperas, and perhaps in analogy,<unk> (II) and zinc sulfate were known respectively as green and white copperas. It is on the World Health Organization's List of Essential Medicines. In 2019, it was the 103rd most commonly prescribed medication in the United States, with more than 6million prescriptions.
Iron
Zinc
Copper 
Biotin
Folate
Selenous acid
Calamine
Sybil 