estanho

Estanho is the chemical element with symbol Sn and atomic number 50. It is a soft, malleable, silvery-white metal, classed as a post-transition metal. It has a relatively low melting point and good resistance to corrosion due to a protective oxide film that forms on its surface.

Occurrence and production: The primary tin ore is cassiterite, tin oxide (SnO2). Tin is typically extracted by mining cassiterite and reducing the oxide in a smelting process. Major producers include China and Indonesia, with notable output from Peru and Bolivia; tin deposits also occur in Africa and other regions.

Properties and forms: Tin melts at 231.93 degrees Celsius and has a density of about 7.31 g/cm3. It exhibits allotropy, existing as white tin at room temperature but capable of transforming into a brittle grey tin under certain conditions, a phenomenon historically known as tin pest. Tin readily forms alloys, notably bronze (with copper) and pewter (tin combined with antimony, copper or lead).

Applications: Tin is widely used in solder for electronics, in tinplate coatings for food cans, and as a component in bronze and pewter alloys. Tin oxide and other tin compounds have applications in ceramics, glass, and various industrial processes.

Environment and safety: Elemental tin is of relatively low toxicity, but tin whiskers can develop on tin coatings used in electronics and may cause short circuits. Mining, smelting and refining can have environmental impacts; recycling plays an important role in supply.

History: Tin has been mined for millennia and was central to the Bronze Age, influencing ancient trade and economies. Today it remains essential in electronics, coatings, and alloys.