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Tin

2007 Schools Wikipedia Selection. Related subjects: Chemical elements


                50                 indium ← tin → antimony
                Ge
                ↑
                Sn
                ↓
                Pb

                                  Periodic Table - Extended Periodic Table

                                                                   General
                                          Name, Symbol, Number tin, Sn, 50
                                               Chemical series poor metals
                                             Group, Period, Block 14, 5, p
                                          Appearance silvery lustrous gray
                                             Atomic mass 118.710 (7) g/mol
                               Electron configuration [Kr] 4d^10 5s^2 5p^2
                                       Electrons per shell 2, 8, 18, 18, 4
                                                       Physical properties
                                                               Phase solid
                              Density (near r.t.) (white) 7.265 g·cm^−3
                               Density (near r.t.) (gray) 5.769 g·cm^−3
                                    Liquid density at m.p. 6.99 g·cm^−3
                                                   Melting point 505.08  K
                                                (231.93 ° C, 449.47 ° F)
                                                      Boiling point 2875 K
                                                    (2602 ° C, 4716 ° F)
                                  Heat of fusion (white) 7.03 kJ·mol^−1
                           Heat of vaporization (white) 296.1 kJ·mol^−1
                                            Heat capacity (25 °C) (white)
                                                27.112 J·mol^−1·K^−1

   CAPTION: Vapor pressure

                                      P/Pa   1    10  100  1 k  10 k 100 k
                                     at T/K 1497 1657 1855 2107 2438 2893

                                                         Atomic properties
                                              Crystal structure tetragonal
                                                     Oxidation states 4, 2
                                                       ( amphoteric oxide)
                                    Electronegativity 1.96 (Pauling scale)
                                                       Ionization energies
                                           ( more) 1st: 708.6 kJ·mol^−1
                                                  2nd: 1411.8 kJ·mol^−1
                                                  3rd: 2943.0 kJ·mol^−1
                                                      Atomic radius 145 pm
                                              Atomic radius (calc.) 145 pm
                                                    Covalent radius 141 pm
                                               Van der Waals radius 217 pm
                                                             Miscellaneous
                                                 Magnetic ordering no data
                                 Electrical resistivity (0 °C) 115 nΩ·m
                       Thermal conductivity (300 K) 66.8 W·m^−1·K^−1
                       Thermal expansion (25 °C) 22.0 µm·m^−1·K^−1
               Speed of sound (thin rod) ( r.t.) (rolled) 2730   m·s^−1
                                                    Young's modulus 50 GPa
                                                      Shear modulus 18 GPa
                                                       Bulk modulus 58 GPa
                                                        Poisson ratio 0.36
                                                         Mohs hardness 1.5
                                                   Brinell hardness 51 MPa
                                             CAS registry number 7440-31-5
                                                         Selected isotopes

                   CAPTION: Main article: Isotopes of tin

                            iso     NA   half-life   DM   DE ( MeV)   DP
                           ^112Sn 0.97%  Sn is stable with 62 neutrons
                           ^114Sn 0.65%  Sn is stable with 64 neutrons
                           ^115Sn 0.34%  Sn is stable with 65 neutrons
                           ^116Sn 14.54% Sn is stable with 66 neutrons
                           ^117Sn 7.68%  Sn is stable with 67 neutrons
                           ^118Sn 24.23% Sn is stable with 68 neutrons
                           ^119Sn 8.59%  Sn is stable with 69 neutrons
                           ^120Sn 32.59% Sn is stable with 70 neutrons
                           ^122Sn 4.63%  Sn is stable with 72 neutrons
                           ^124Sn 5.79%  Sn is stable with 74 neutrons
                           ^126Sn syn    ~1 E5 y   Beta^- 0.380     ^126Sb

                                                                References

   The alchemical symbol for tin
   Enlarge
   The alchemical symbol for tin
   Tin ore
   Enlarge
   Tin ore

   Tin ( IPA: /ˈtɪn/) is a chemical element in the periodic table that has
   the symbol Sn ( Latin: stannum) and atomic number 50. This silvery,
   malleable poor metal that is not easily oxidized in air and resists
   corrosion, is found in many alloys and is used to coat other metals to
   prevent corrosion. Tin is obtained chiefly from the mineral
   cassiterite, where it occurs as an oxide.

Notable characteristics

   Tin is a malleable, ductile, highly crystalline, silvery-white metal;
   when a bar of tin is bent, a strange crackling sound known as the "tin
   cry" can be heard due to the breaking of the crystals. This metal
   resists corrosion from distilled, sea and soft tap water, but can be
   attacked by strong acids, alkalis, and by acid salts. Tin acts as a
   catalyst when oxygen is in solution and helps accelerate chemical
   attack.

   Tin forms the dioxide SnO[2] when it is heated in the presence of air.
   SnO[2], in turn, is feebly acidic and forms stannate (SnO[3]^-2) salts
   with basic oxides. Tin can be highly polished and is used as a
   protective coat for other metals in order to prevent corrosion or other
   chemical action. This metal combines directly with chlorine and oxygen
   and displaces hydrogen from dilute acids. Tin is malleable at ordinary
   temperatures but is brittle when it is heated.

Allotropes

   Chemically tin shows properties intermediate between those of metals
   and non-metals, just as the semi-conductors silicon and germanium do.
   Tin has two allotropes at normal pressure and temperature, gray tin,
   and white tin.

   Below 13.2 ° C it exists as gray or alpha tin, which has a cubic
   crystal structure similar to silicon and germanium. Gray tin has no
   metallic properties at all, is a dull-gray powdery material, and has no
   known uses.

   When warmed above 13.2 ° C tin changes into white or beta tin, which is
   metallic and has a tetragonal structure. Converting gray tin power into
   white tin produces white tin powder. To convert powdery gray tin into
   solid white tin the temperature must be raised above the melting point
   of tim.

   Gray tin can be a real problem, since metallic white tin will slowly
   convert to gray tin if it is held for a long time below 13.2 ° C. The
   metallic surface of white tin becomes covered with a gray powder which
   is easily rubbed off. The gray patches slowly expand until all of the
   tin in the object is converted from the metal to the powder, at which
   point it totally loses its structural integrity and falls to pieces.
   This process is know as tin disease or tin pest. Tin pest was a
   particular problem in nothern Europe in the 18th century as organ pipes
   made of tin would sometime completly disintergrate during long cold
   winters. The transformation can be prevented by the the addition of
   antimony or bismuth.

Applications

   Tin bonds readily to iron, and has been used for coating lead or zinc
   and steel to prevent corrosion. Tin-plated steel containers are widely
   used for food preservation, and this forms a large part of the market
   for metallic tin. Speakers of British English call them "tins";
   Americans call them " cans" or "tin cans". One thus-derived use of the
   slang term " tinnie" or "tinny" means "can of beer". The tin whistle is
   so called because it was first mass-produced in tin-plated steel.

   Other uses:
     * Some important tin alloys are: bronze, bell metal, Babbitt metal,
       die casting alloy, pewter, phosphor bronze, soft solder, and White
       metal.
     * The most important salt formed is stannous chloride, which has
       found use as a reducing agent and as a mordant in the calico
       printing process. Electrically conductive coatings are produced
       when tin salts are sprayed onto glass. These coatings have been
       used in panel lighting and in the production of frost-free
       windshields.
     * Most metal pipes in a pipe organ are made of varying amounts of a
       tin/lead alloy, with 50% / 50% being the most common. When this
       alloy cools, the lead cools slightly faster and makes a mottled or
       spotted effect. This metal alloy is referred to as spotted metal.
     * Window glass is most often made via floating molten glass on top of
       molten tin (creating float glass) in order to make a flat surface
       (this is called the " Pilkington process").
     * Tin is one of the two basic elements used since the Rennaisance in
       the manufacture of organ pipes (the other being lead). The amount
       of tin in the pipe defines the pipe's tone, tin being the most
       tonally resonant of all metals.
     * Tin is also used in solders for joining pipes or electric circuits,
       in bearing alloys, in glass-making, and in a wide range of tin
       chemical applications. Although of higher melting point than a
       lead-tin alloy, the use of pure tin or tin alloyed with other
       metals in these applications is rapidly supplanting the use of the
       previously common lead–containing alloys in order to eliminate the
       problems of toxicity caused by lead.
     * Tin foil was once a common wrapping material for foods and drugs;
       replaced in the early 20th century by the use of aluminium foil,
       which is now commonly referred to as tin foil. Hence one use of the
       slang term " tinnie" or "tinny" for a small retail package of a
       drug such as cannabis or for a can of beer.

   Tin becomes a superconductor below 3.72 K. In fact, tin was one of the
   first superconductors to be studied; the Meissner effect, one of the
   characteristic features of superconductors, was first discovered in
   superconducting tin crystals. The niobium-tin compound Nb[3]Sn is
   commercially used as wires for superconducting magnets, due to the
   material's high critical temperature (18 K) and critical magnetic field
   (25 T). A superconducting magnet weighing only a couple of kilograms is
   capable of producing magnetic fields comparable to a conventional
   electromagnet weighing tons.

History

   Tin ( Anglo-Saxon, tin, Latin stannum) is one of the earliest metals
   known and was used as a component of bronze from antiquity. Because of
   its hardening effect on copper, tin was used in bronze implements as
   early as 3,500 BC. Tin mining is believed to have started in Cornwall
   and Devon ( esp Dartmoor) in Classical times, and a thriving tin trade
   developed with the civilizations of the Mediterranean. However the pure
   metal was not used until about 600 BC. The last Cornish Tin Mine, at
   South Crofty near Camborne closed in 1998 bringing 4000 years of mining
   in Cornwall to an end.

   The word "tin" has cognates in many Germanic and Celtic languages. The
   American Heritage Dictionary speculates that the word was borrowed from
   a pre-Indo-European language.

   In modern times, the word "tin" is often (improperly) used as a generic
   phrase for any silvery metal that comes in thin sheets. Most everyday
   objects that are commonly called tin, such as aluminium foil, beverage
   cans, and tin cans, are actually made of steel or aluminium, although
   tin cans do contain a thin coating of tin to inhibit rust. Likewise,
   so-called "tin toys" are usually made of steel, and may or may not have
   a thin coating of tin to inhibit rust.

Occurrence

   About 35 countries mine tin throughout the world. Nearly every
   continent has an important tin-mining country. Tin is produced by
   reducing the ore with coal in a reverberatory furnace. This metal is a
   relatively scarce element with an abundance in the Earth's crust of
   about 2 ppm, compared with 94 ppm for zinc, 63 ppm for copper, and 12
   ppm for lead. Most of the world's tin is produced from placer deposits;
   at least one-half comes from Southeast Asia. The only mineral of
   commercial importance as a source of tin is cassiterite (SnO[2]),
   although small quantities of tin are recovered from complex sulfides
   such as stannite, cylindrite, franckeite, canfieldite, and teallite.
   Secondary, or scrap, tin is also an important source of the metal.

   Tasmania hosts some important deposits of historical importance, most
   importantly Mount Bischoff and Renison Bell.

Isotopes

   Tin is the element with the greatest number of stable isotopes (ten).
   28 additional unstable isotopes are known.

Compounds

   For discussion of Stannate compounds (SnO[3]^2-) see Stannate. For
   Stannite (SnO[2]^-) see Stannite. See also Stannous hydroxide
   (Sn(OH)[2]), Stannic acid (Stannic Hydroxide - Sn(OH)[4]), Tin dioxide
   (Stannic Oxide - SnO[2]), Tin(II) oxide (Stannous Oxide - SnO), Tin(II)
   chloride (SnCl[2]), Tin(IV) chloride (SnCl[4])

Biologic effects of organic tin compounds

   The small amount of tin that is found in canned foods is not harmful to
   humans. Certain organic tin compounds, organotin, such as triorganotins
   (see tributyltin oxide) are toxic and are used as industrial fungicides
   and bactericides.

   Retrieved from " http://en.wikipedia.org/wiki/Tin"
   This reference article is mainly selected from the English Wikipedia
   with only minor checks and changes (see www.wikipedia.org for details
   of authors and sources) and is available under the GNU Free
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