Many examples of ionic sulfates are known, and many of these are highly soluble in water. Exceptions include calcium sulfate, strontium sulfate, and barium sulfate, which are poorly soluble. The barium derivative is useful in the gravimetric analysis of sulfate: one adds a solution of, perhaps, barium chloride to a solution containing sulfate ions. The appearance of a white precipitate, which is barium sulfate, indicates that sulfate anions are present.
The sulfate ion can act as a ligand attaching either by one oxygen (monodentate) or by two oxygens as either a chelate or a bridge. An example is the neutral metal complex PtSO4P(C6H5)32 where the sulfate ion is acting as a bidentate ligand. The metal-oxygen bonds in sulfate complexes can have significant covalent character
Magnesium sulfate is a chemical compound containing magnesium and sulfate, with the formula MgSO4. It is often encountered as the heptahydrate, MgSO4·7H2O, commonly called Epsom salts. Anhydrous magnesium sulfate is used as a drying agent. Since the anhydrous form is hygroscopic (readily absorbs water from the air) and therefore harder to weigh accurately, the hydrate is often preferred when preparing solutions, for example in medical preparations. Epsom salts have traditionally been used as a component of bath salts.
Iron(III) sulfate, is a compound of Iron and sulfate (made of sulfur and oxygen atoms). The compound is different from the more common Iron(II) sulfate in that the ratio of sulfate ions to iron ions is larger.
Ferric sulfate is produced on a large scale by reacting sulfuric acid with a hot solution of ferrous sulfate, using an oxidizing agent (such as nitric acid or hydrogen peroxide).
Manganese(II) sulfate is the inorganic compound with the formula MnSO4. This colorless deliquescent solid is a commercially significant manganese(II) salt. Approximately 260M kg/y were produced worldwide in 2005. It is the precursor to manganese metal and many chemical compounds. Mn-deficient soil is remediated with this salt.
Like many metal sulfates, manganese sulfate forms a variety of hydrates: mono hydrate, tetra hydrate, pentahydrate, heptahydrate. The mono hydrate is most common. All of these salts are faintly pink. The pale color of Mn(II) salts is characteristic of high-spin complexes with the d5 configuration.
Potassium sulfate (K2SO4) (in British English potassium sulfate, also called sulfate of potash or archaically known as potash of sulfur) is a non-flammable white crystalline salt which is soluble in water. The chemical is commonly used in fertilizers, providing both potassium and sulfur.
Barium sulfate is frequently used clinically as a radio contrast agent for X-ray imaging and other diagnostic procedures. It is most often used in imaging of the GI tract during what is colloquially known as a 'Barium meal'.
It is administered, orally or by enema, as a suspension of fine particles in an aqueous solution (often with sweetening agents added). Although barium is a heavy metal, and its water-soluble compounds are often highly toxic, the extremely low solubility of barium sulfate protects the patient from absorbing harmful amounts of the metal. Barium sulfate is also readily removed from the body, unlike Thorotrast, which it replaced. Due to the relatively high atomic number (Z = 56) of barium, its compounds absorb X-rays more strongly than compounds derived from lighter nuclei.
Lithium sulfate is a white inorganic salt used to treat bipolar disorder (see Lithium pharmacology). It is soluble in water, though it does not follow the usual trend of solubility versus temperature - its solubility in water decreases with increasing temperature. This property is shared with few inorganic compounds, such as the lanthanide sulfates.
Ammonium sulfate is prepared commercially by reacting ammonia with sulfuric acid (H2SO4). Ammonium sulfate is prepared commercially from the ammoniacal liquor of gas-works and is purified by recrystallisation. It forms large rhombic prisms, has a somewhat saline taste and is easily soluble in water. The aqueous solution on boiling loses some ammonia and forms an acid sulfate.
Aluminum sulfate, written as Al2(SO4)3 or Al2O12S3, is a widely used industrial chemical. It is sometimes incorrectly referred to as alum, as it is closely related to this group of compounds. It occurs naturally as the mineral alunogenite. It is frequently used as a flocculating agent in the purification of drinking water and waste water treatment plants, and also in paper manufacturing.
Aluminum sulfate is rarely, if ever, encountered as the anhydrous salt. It forms a number of different hydrates, of which the hexadecahydrate Al2(SO4)3o16H2O and octadecahydrate Al2(SO4)3o18H2O are the most common.