A sulfate is a chemical compound containing the ion SO₄^2-, or its corresponding radical. Many sulfates are found in nature as mineral deposits, including barium sulfate (BaSO₄, barite), calcium sulfate (gypsum, alabaster, and selenite), and strontium sulfate (celestite).Potassium sulfate (K₂SO₄) and magnesium sulfate (MgSO₄7H₂O or Epsom salts) also occur naturally. Some sulfates are produced as byproducts in other manufacturing operations. For instance, sodium sulfate is produced during battery recycling and rayon manufacturing.

Sulfates are salts or esters of sulfuric acid, H₂SO₄. One or both of the hydrogens are replaced with a metal or a radical (ammonium or ethyl). Sulfates that have both hydrogens replaced are known as normal sulfates. Those with only one hydrogen replaced are known as hydrogen sulfates, acid sulfates, or bisulfates. Double sulfates contain two different metals and two sulfate radicals. Organic sulfates are esters and are formed by...