The Element Zinc
[Click for Isotope Data]
Atomic Number: 30
Atomic Weight: 65.38
Melting Point: 692.68 K (419.53°C or 787.15°F)
Boiling Point: 1180 K (907°C or 1665°F)
Density: 7.134 grams per cubic centimeter
Phase at Room Temperature: Solid
Element Classification: Metal
Period Number: 4 Group Number: 12 Group Name: none
What's in a name? From the German word zink.
Say what? Zinc is pronounced as ZINK.
History and Uses:
Although zinc compounds have been used for at least 2,500 years in the production of brass, zinc wasn't recognized as a distinct element until much later. Metallic zinc was first produced in India sometime in the 1400s by heating the mineral calamine (ZnCO3) with wool. Zinc was rediscovered by Andreas Sigismund Marggraf in 1746 by heating calamine with charcoal. Today, most zinc is produced through the electrolysis of aqueous zinc sulfate (ZnSO4).
Roughly one third of all metallic zinc produced today is used in a process known as galvanization. During galvanization, an object that is subject to corrosion, such as an iron nail, is given a protective coating of zinc. The zinc can be applied to an object by dipping it in a pool of molten zinc, but it is most often applied through an electroplating process. Sacrificial zinc anodes are used in cathodic protection systems to protect exposed iron from corrosion. Metallic zinc is also used to make dry cell batteries, roof cladding and die castings.
Zinc is used to make many useful alloys. Brass, an alloy of zinc that contains between 55% and 95% copper, is probably the best known zinc alloy. Brass was first used about 2,500 years ago and was widely used by the ancient Romans, who used it to make such things as coins, kettles and decorative items. Brass is still used today, particularly in musical instruments, screws and other hardware that must resist corrosion. Zinc is alloyed with lead and tin to make solder, a metal with a relatively low melting point used to join electrical components, pipes and other metallic items. Prestal®, an alloy containing 78% zinc and 22% aluminum, is a strange material that is nearly as strong as steel but is molded as easily as plastic. Nickel silver, typewriter metal, spring brass and German silver are other common zinc alloys.
Zinc oxide (ZnO), a common zinc compound, forms when metallic zinc is exposed to the air and forms a protective coating that protects the rest of the metal. Zinc oxide is used in paints, some rubber products, cosmetics, pharmaceuticals, plastics, printing inks, soap and batteries, among other things. Zinc sulfide (ZnS), another zinc compound, glows when it is exposed to ultraviolet light, X-rays or electrons and is used to make luminous watch dials, television screens and fluorescent light bulbs. Zinc chloride (ZnCl2) is another zinc compound that is used to protect wood from decay and insects.
Estimated Crustal Abundance: 7.0×101 milligrams per kilogram
Estimated Oceanic Abundance: 4.9×10-3 milligrams per liter
Number of Stable Isotopes: 3 (View all isotope data)
Ionization Energy: 9.394 eV
Oxidation States: +2
3s2 3p6 3d10