Tin

Tin

Tin is a chemical element with the symbol Sn (from Latin: stannum) and atomic number 50. Tin is a silvery metal that characteristically has a faint yellow hue. Tin is soft enough to be cut with little force. When a bar of tin is bent, the so-called “tin cry” can be heard as a result of twinning in tin crystals; this trait is shared by indium, cadmium, zinc, and frozen mercury. Pure tin after solidifying presents a mirror-like appearance similar to most metals. In most tin alloys (such as pewter) the metal solidifies with a dull gray color. Tin is a post-transition metal in group 14 of the periodic table of elements. It is obtained chiefly from the mineral cassiterite, which contains stannic oxide, SnO2. Tin shows a chemical similarity to both of its neighbors in group 14, germanium and lead, and has two main oxidation states, +2 and the slightly more stable +4. Tin is the 49th most abundant element on Earth and has, with 10 stable isotopes, the largest number of stable isotopes in the periodic table, thanks to its magic number of protons. It has two main allotropes: at room temperature, the stable allotrope is β-tin, a silvery-white, malleable metal; at low temperatures it is less dense grey α-tin, which has the diamond cubic structure. Metallic tin does not easily oxidize in air and water. The first tin alloy used on a large scale was bronze, made of 1⁄8 tin and 7⁄8 copper, from as early as 3000 BC. After 600 BC, pure metallic tin was produced. Pewter, which is an alloy of 85–90% tin with the remainder commonly consisting of copper, antimony, and sometimes lead, has been used for flatware since the Bronze Age. In modern times, tin is used in many alloys, most notably tin / lead soft solders, which are typically 60% or more tin, and in the manufacture of transparent, electrically conducting films of indium tin oxide in optoelectronic applications. Another large application is corrosion-resistant tin plating of steel. Because of the low toxicity of inorganic tin, tin-plated steel is widely used for food packaging as tin cans. Some organotin compounds can be extremely toxic.

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