Zinc, also known as zinc, is a chemical element of the periodic table, with atomic number 30 and symbol Zn, and is located in one of the transition metal groups. The etymology of zinc apparently comes from the German, Zincken or Zacken (tips, teeth), to indicate the jagged appearance of the mineral calamine, later it was used for the metal obtained from it.
This metal is not found freely in nature, combined it is found abundantly, mainly in the mineral sphalerite or blende (ZnS), as well as the minerals zincite (ZnO), hemimorphite, esmitsionite and franklinite.
Zinc is extracted from natural sulfides (blendes) by calcination and reduction, another method is to treat ground ores with sulfuric acid, forming zinc sulfate that is then subjected to electrolysis.
Among its properties are that it is bluish-white in color; it is rough and brittle (it softens between 100-150 ºC) to the point that it can be pulverized, it has a melting point of 419 ºC and a boiling point of 907 ºC.
It has, of all metals, the highest coefficient of thermal expansion. And of the heavy metals, it is the most electropositive; hence it displaces the other metals from their solutions. This is the reason why zinc is used as an electro-negative in dry cells and others.
In air, zinc oxidizes, but only slightly, perhaps by the formation of a self-protective oxide and carbonate layer. Because of this ability to resist corrosion well, and because it provides cathodic protection to iron, it is often used to coat this metal to prevent rust from forming. The iron thus protected is called galvanized iron.
Zinc is a very important metal as it has many industrial applications; one of them are alloys, such as brass (copper and zinc alloys), and Al and Mg alloys. Zinc oxide is used as a pigment in paint, it is also used as a filler in rubber tires and as an antiseptic ointment in medicine.
Zinc salts kill putrefactive bacteria and are therefore used to impregnate wood and posts, preserving them from putrefaction, highlighting that these salts are poisonous to animals and man.
