Alloying elements such as copper, antimony, bismuth, cadmium, and silver increase the hardness of tin. Ĭommercial grades of tin (99.8% tin content) resist transformation because of the inhibiting effect of small amounts of bismuth, antimony, lead, and silver present as impurities. With the addition of antimony or bismuth the transformation might not occur at all, increasing durability. Al, Zn, etc.) lower it well below 0 ☌ (32 ☏). The α-β transformation temperature is 13.2 ☌ (55.8 ☏), but impurities (e.g. Some unverifiable sources also say that, during Napoleon's Russian campaign of 1812, the temperatures became so cold that the tin buttons on the soldiers' uniforms disintegrated over time, contributing to the defeat of the Grande Armée, a persistent legend. In cold conditions β-tin tends to transform spontaneously into α-tin, a phenomenon known as " tin pest" or "tin disease". γ-tin and σ-tin exist at temperatures above 161 ☌ (322 ☏) and pressures above several GPa. α-tin is a dull-gray powdery material with no common uses other than specialized semiconductor applications. α-tin does not have metallic properties because its atoms form a covalent structure in which electrons cannot move freely. α-tin has a diamond cubic crystal structure, as do diamond and silicon. It is stable below 13.2 ☌ (55.8 ☏) and is brittle. α-tin, or gray tin, is the nonmetallic form. It is metallic and malleable, and has body-centered tetragonal crystal structure. Β-tin, also called white tin, is the allotrope (structural form) of elemental tin that is stable at and above room temperature. Β–α transition of tin at −40 ☌ (time lapse one second of the video is one hour in real time) The melting point is further lowered to 177.3 ☌ (351.1 ☏) for 11 nm particles. Tin melts at about 232 ☌ (450 ☏), the lowest in group 14. When a bar of tin is bent a crackling sound known as the " tin cry" can be heard from the twinning of the crystals. Tin is a soft, malleable, ductile and highly crystalline silvery-white metal. Some organotin compounds can be extremely toxic.Ĭharacteristics Physical Droplet of solidified molten tin Because of the low toxicity of inorganic tin, tin-plated steel is widely used for food packaging as " tin cans". Another large application is corrosion-resistant tin plating of steel. 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. Pewter, which is an alloy of 85–90% tin with the remainder commonly consisting of copper, antimony, bismuth, and sometimes lead and silver, has been used for flatware since the Bronze Age. After 600 BC, pure metallic tin was produced. The first tin alloy used on a large scale was bronze, made of 1⁄ 8 tin and 7⁄ 8 copper (12.5% and 87.5% respectively), from as early as 3000 BC. Metallic tin does not easily oxidize in air and water. 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. 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, due to its magic number of protons. 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. It is obtained chiefly from the mineral cassiterite, which contains stannic oxide, SnOĢ. Tin is a post-transition metal in group 14 of the periodic table of elements. pewter) the metal solidifies with a dull grey colour. Pure tin after solidifying presents a mirror-like appearance similar to most metals. When 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 mercury in its solid state. A silvery-coloured metal, tin is soft enough to be cut with little force, and a bar of tin can be bent by hand with little effort. Tin is a chemical element it has symbol Sn (from Latin stannum) and atomic number 50.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |