7440-31-5

Raw materials And Preparation Products

Hazard Information

Material Safety Data Sheet(MSDS)

Questions And Answer

• Introduction

  Tin is known from ancient times. Its alloy, bronze, containing 10 to 15% tin has been in use in weapons and tools for millennia.
  The most important mineral of tin is cassiterite, SnO2. It occurs in the form of alluvial sand. Also, it is found embedded in granite rocks. Other tin-bearing minerals are stannite and tealite. Abundance of tin in the earth’s crust is estimated to be 2.3 mg/kg. Tin is used for plating steel to make “tin cans” for preserving food. Also, tin is coated over other metals to prevent corrosion. An important application of tin is to produce float glass, made by floating molten glass on molten tin which is used for windows. A number of tin alloys have wide industrial applications and include bronze, solder, Babbit metal, White metal, type metal, fusible metal, and phosphor bronze. A tin-niobium alloy that is superconducting at low temperatures is used in constructing super magnets. Tin also is in wrapping foil and collapsible tube. ;

• Chemical Properties

  Tin is a ductile, malleable, lustrous solid with a gray to almost silver-white color. Tin forms covalent bonds with carbon forming a variety of organometallic or organotin compounds, and the physical and chemical properties differ for various compounds such as Tin II (SnO) and Tin IV (SnO2), organotins, and inorganic tin compounds. Tin compounds are generally insoluble in water and have vapor pressures of approximately 0mmHg. Tin is not easily oxidized and resists corrosion; however, powdered tin has a tendency to oxidize, especially at high humidity.
  ;

• Physical Properties

  Silvery-white metal at ordinary temperature; slowly changes to gray below 13.2°C; soft, malleable, and somewhat ductile; Brinell hardness 2.9. Tin has two allotropic forms: (1) white tin, the beta form, and (2) gray tin, the alpha form. The white tin (beta form) has a tetragonal structure. When cooled below 13.2°C, its color slowly changes from white to gray, the beta allotrope converting to alpha (gray tin). The presence of small amounts of antimony or bismuth prevents this transformation from white to gray tin. Other impurities such as zinc or aluminum promote change from white to gray tin.
  Some other physical properties are: density 7.28 g/cm3 (white), 5.75 g/cm3 (gray) and 6.97 g/cm3 (liquid at the melting point); melts at 231.9°C; vaporizes at 2,602°C; electrical resistivity 11.0 and 15.5 microhm-cm at 0 and 100°C, respectively; viscosity 1.91 and 1.38 centipoise at 240 and 400°C, respectively; surface tension 5.26 and 5.18 dynes/cm at 300 and 400°C, respectively; modulus of elasticity 6 – 6.5x106 cgs psi; magnetic suspectibility 0.027x10–6 cgs units; thermal neutron absorption cross section 0.625 barns; insoluble in water; soluble in HCl, H2SO4, aqua regia, and alkalies; slightly soluble in dilute nitric acid. ;

• Uses

  Tin is primarily produced from the ore cassiterite (SnO2). It has a variety of industrial and domestic uses; its usefulness stems from its pliability and ability to readily form compounds and alloys with other metals, inorganic compounds, and organic compounds. Tin metal is used to line cans for storing and transporting food, beverages, and aerosols. Bronze is an alloy of tin and copper; pewter is an alloy of tin with various amounts of antimony, copper, bismuth, and sometimes lead. Soldering compounds are made with tin alloys. Inorganic tin is used in making toothpaste, perfumes, soaps, coloring agents, food additives, dyes, and in the glass industry.
  Tributyltin is used as a slime control in paper mills, for disinfection of circulating industrial cooling waters, as antifouling agents, and in the preservation of wood. Tributyltin, triphenyltin, and tricyclohexyltin are used in agriculture as fungicides, anti-helminthics, miticides, herbicides, nematocides, ovicides, molluscicides, ascaricides, pesticides, in industry as biocides, and as antifouling agents for large ship bottoms and fishery farm nets. In the past, several organometallic metallocene complexes of tin have been identified as having antitumor activity. Tin protoporphyrin has been used to treat acute hepatic porphyria. Niobium– tin compounds are used to build superconducting magnets.;

• Production

  Tin is produced commercially from mineral cassiterite, SnO2. The mineral is mined from alluvial sand deposits by different techniques, such as various dredging (usually applied to low-grade deposits), gravel-pump mining (on level ground), and open-pit mining. The ore is broken up mechanically by blasting and drilling. It then is crushed and ground to produce finely divided material that can be separated by gravity concentration and froth flotation. Tin concentrates so obtained require removal of sulfide before smelting. This is done by roasting concentrates at high temperatures which removes both sulfur and arsenic. Lead sulfide is converted to lead sulfate but all other associated metal sulfides, such as those of iron, copper, zinc, and bismuth, are converted to oxides.
  Tin is produced from oxide by heating at high temperatures with carbon. Small amounts of limestone and sand are added to coal for this reduction and to promote removal of impurities. Primary smelting is carried out in a reverbaratory furnace at a temperature between 1,200 to 1,300°C. Electric arc furnaces also are used. The molten tin collected at the bottom is cast into slabs. The slags are resmelted at a higher temperature, up to 1,480°, in the same type of furnaces to recover more tin that is combined as silicates.
  Tin obtained above contains small amounts of impurities. It is purified by resmelting in a small reverberatory furnace at a temperature just above the melting point of tin. The molten tin is drawn out, separating iron, copper, arsenic, antimony, and other metals. Purified tin is further refined by boiling or polling processes to remove traces of impurity metals, such as lead and bismuth. ;

• Reactions

  At ordinary temperatures tin is stable in air. It actually forms a very thin protective oxide film. In powder form, and especially in the presence of moisture, it oxidizes. When heated with oxygen it forms tin(IV) oxide, SnO2.Tin reacts with all halogens forming their halides. Reaction with fluorine is slow at ordinary temperatures; however, chlorine, bromine and iodine readily react with the metal.
  Tin is attacked by concentrated acids. With dilute acids the reaction may be slow or very slow. The metal readily reacts with hot concentrated hydrochloric acid and aqua regia but slowly with cold dilute hydrochloric acid. The reaction also is slow with hot dilute sulfuric acid, which dissolves the metal, particularly in the presence of an oxidizing agent. The reaction with nitric acid is generally slow. Hot concentrated acid converts the metal to an insoluble hydrated tin(IV) oxide. The reaction is rapid with moist sulfur dioxide or sulfurous acid, chlorosulfonic, and pyrosulfuric acids. Organic acids such as, acetic, oxalic, and citric acids react slowly with the metal, particularly in the presence of air or an oxidizing agent.
  Strong alkaline solutions of caustic soda or caustic potash dissolve tin forming the stannate, Na2SnO3, or K2SnO3. The metal is stable in dilute solutions of ammonia or sodium carbonate.
  Tin dissolves in solutions of oxidizing salts such as potassium chlorate or potassium persulfate. The metal does not react with neutral salts in aqueous solutions. In air, tin reacts slowly with neutral salts.
  The metal does not combine directly with hydrogen, nitrogen or ammonia gas. ;

Well-known Reagent Company Product Information

Supplier

Related Products