Metallic stearates are metal soaps of an 18-carbon chain fatty acid, known as stearic acid, and various alkali metals like calcium, magnesium, and zinc. They are produced by replacing the carboxylic hydrogen of stearic acid with a metal cation from direct metal, metal oxide, metal hydroxide, metal sulphates, and metal chlorides. The most widely used metallic stearates are Calcium, Magnesium, and Zinc. The long hydrocarbon chain of stearic acid makes the stearate highly water-resistant, good for lubrication, and has a relatively higher melting point as compared to other metallic soaps.
These properties allow its use in a wide range of applications, from simple plastic toys to complex structures in several industries such as polymer & rubber, pharmaceuticals & cosmetics, building & construction, and paints & coatings industry. The structure of metallic stearates is similar to that of a carboxylate salt. It has a head of an alkali metal cation and a tail of stearic acid. The completely saturated hydrocarbon chain of 18-carbons is insoluble in water and thus imparts the hydrophobic nature to metallic stearates.