50
  Sn  
118.710000
Tin

Name: Tin
Symbol: Sn
Atomic Number: 50
Atomic Weight: 118.710000
Family: Carbon Family
CAS RN: 7440-31-5
Description: A silvery-white malleable metal crystalline in structure.
State (25C): Solid
Oxidation states: +2, +4

Molar Volume: 16.31 cm3/mole
Valence Electrons: 5p2

Boiling Point:  2543K, 2270C, 4118F
Melting Point:
505.21K, 232.06C, 449.71F
Electrons Energy Level: 2, 8, 18, 18, 4
Isotopes: 28 + 10 Stable
Heat of Vaporization: 295.8 kJ/mol
Heat of Fusion: 7.029 kJ/mol
Density: 7.31 g/cm3 @ 300K
Specific Heat: 0.227 J/gK
Atomic Radius: 1.72
Ionic Radius: 0.69
Electronegativity: 1.96 (Pauling); 1.72 (Allrod Rochow)
Vapor Pressure: 5.78E-21 Pa @ 232.06C
Named after the Etruscan god Tinia, the chemical symbol for tin is taken from the Latin stannum.   Tin (Old English:  tin, Old Latin:  plumbum candidum, Old German:  tsin, Late 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 lone 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. The later name of "stannum" and its Romance derivatives come from the Lead-Silver alloy of the same name for the winning of the latter in ores; its former "Stagnum" was the word for a stale pool or puddel.

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 aluminum foil, beverage cans, and tin cans, are actually made of steel or aluminum, although tin cans (tinned 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.

6
C
12.02
14
Si
28.08
32
Ge
72.15
50
Sn
118.7
82
Pb
207.2
114
Uuq
285.0
75px-Tin-symbol.jpg (2268 bytes)

Alchemical Symbol, Tin/Jupiter

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.   It has the look of freshly cut aluminum but the feel of lead.  Polished tin is slightly bluish.

1s2 2s2p6 3s2p6d10 4s2p6d10 5s2p2

Tin forms the Dioxide SnO2 when it is heated in the presence of air.   SnO2, in turn, is feebly acidic and forms Stannate (SnO3-2) 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.

tin1.jpg (1466 bytes) tin2.jpg (1462 bytes) tin3.jpg (1560 bytes) tin4.jpg (1523 bytes) tin5.jpg (1347 bytes) tin_jupiter.jpg (1327 bytes)

Additional Representations of Alchemical Symbols for Tin

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, SnO2, although small quantities of tin are recovered from complex Sulfides such as Stannite, Cylindrite, Franckeite, Canfieldite, and Teallite.  Tin is primarily extracted by roasting Cassiterite in a furnace with Carbon. 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.

Allotropes

Two allotropes of tin occur near room temperature. The first form of Tin is called Gray Tin or alpha Tin has a cubic crystal structure similar to Silicon and Germanium.  It is stable at temperatures below 13.2C (55.76F).  There are few, if any, uses for Gray Tin.  At temperatures above 13.2C, Gray Tin slowly turns into Tin's second form, White or beta Tin.  White Tin is the normal form which is metallic and has a tetragonal structure.  Unfortunately, White Tin will turn into Gray Tin if its temperature falls below 13.2C.  This change can be prevented if small amounts of Antimony or Bismuth are added to White Tin.

Chemically tin shows properties intermediate between those of metals and non-metals, such as the semiconductors Silicon and Germanium. 

Gray Tin has no metallic properties at all, is a dull-gray powdery material, and has no known uses.

As stated above: When warmed above 13.2C Tin changes into white or beta Tin, which is metallic and has a tetragonal structure.  Converting gray Tin powder 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 Tin.

1s2
2s2 2p6
3s2 3p6 3d10
4s2 4p6 4d10
5s2 5p2

Gray Tin can be a real problem, since metallic white Tin will slowly convert to gray Tin when held for a long time below 13.2Celsius.  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 known as Tin Disease or Tin Pest.  Tin Pest was a particular problem in northern Europe in the 18th century as organ pipes made of Tin would sometimes completely disintegrate during long cold winters.  The transformation can be prevented by the addition of Antimony or Bismuth.

Applications

Perhaps one of the most familiar of tin compounds, SnF2, Tin (II) Fluoride, goes by the trade name of fluoristan and is found in some fluoride toothpastes.   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 "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.

Tin becomes a superconductor below 3.72oK.  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 Nb3Sn is commercially used as wires for superconducting magnets, due to the material's high critical temperature (18oK) and critical magnetic field (25T).  A superconducting magnet weighing only a couple of kilograms is capable of producing magnetic fields comparable to a conventional electromagnet weighing tons.

Compounds

Stannous Hydroxide, Sn(OH)2 Stannic Acid, Stannic Hydroxide - Sn(OH)4
Cassiterite, Tin Dioxide, Stannic Oxide - SnO2 Tin (II) Oxide, Stannous Oxide - SnO
Tin (II) Chloride, SnCl2 Tin (IV) Chloride, SnCl4
Stannous Fluoride, SnF2

Tin  also forms Stannate (SnO32-) and Stannite (SnO2-) compounds.

tin.gif (806 bytes)

Alchemical Symbol, Tin

Isotopes

Tin is the element with the greatest number of stable isotopes, 10, which is probably related to the fact that 50 is a "magic number" of protons.  28 additional unstable isotopes are known, including the "doubly magic tin-100 (100Sn) (discovered in 1994).

atom.gif (700 bytes)

Isotope Atomic Mass Half-Life
Sn100 99.939 0.94 seconds
Sn101 100.936 3 seconds
Sn102 101.93 4.5 seconds
Sn103 102.928 7 seconds
Sn104 103.923 20.8 seconds
Sn105 104.9214 31 seconds
Sn106 105.9169 115 seconds
Sn107 106.9157 2.9 minutes
Sn108 107.912 10.3 minutes
Sn109 108.9113 18 minutes
Sn110 109.9079 4.11 hours
Sn111 110.9077 35.3 minutes
Sn112 111.9048 Stable
Sn113 112.9052 115.09 days
Sn114 113.9028 Stable
Sn115 114.9034 Stable
Sn116 115.9017 Stable
Sn117 116.903 Stable
Sn118 117.9016 Stable
Sn119 118.9033 Stable
Sn120 119.9022 Stable
Sn121 120.9042 27.06 hours
Sn122 121.9034 Stable
Sn123 122.9057 129.2 days
Sn124 123.9053 Stable
Sn125 124.9078 9.64 days
Sn126 125.9077 ~100000 years
Sn127 126.9104 2.1 hours
Sn128 127.9105 59.07 minutes
Sn129 128.913 2.23 minutes
Sn130 129.9139 3.72 minutes
Sn131 130.9169 56 seconds
Sn132 131.9177 39.7 seconds
Sn133 132.9238 1.45 seconds
Sn134 133.928 1.12 seconds
Sn135 134.935 >150 ns
Sn136 135.939 >150 ns
Sn137 136.946 >150 ns

Precautions

40px-Skull_and_crossbones.svg.jpg (1420 bytes) The small amount of Tin that is found in canned foods is not harmful to humans. Certain organic Tin compounds, Organotin, such as triorganotins are toxic and are used as industrial fungicides and bactericides.

atom.gif (700 bytes)

Tin Data

Atomic Radius (): 1.72
Atomic Volume cm3/mol : 16.3cm3/mol
Covalent Radius: 1.41
Crystal Structure: Tetragonal
Ionic Radius: 0.69

Chemical Properties

Electrochemical Equivalents: 1.1071 g/amp-hr
Electron Work Function: 4.42eV
Electronegativity: 1.96 (Pauling); 1.72 (Allrod Rochow)
Heat of Fusion: 7.029 kJ/mol
Incompatibilities: Chlorine, Turpentine, Acids, Alkalis
First Ionization Potential: 7.344
Second Ionization Potential: 14.632
Third Ionization Potential: 30.502
Valence Electron Potential: 83.5
Ionization Energy (eV): 7.344 eV

Physical Properties

Atomic Mass Average: 118.71
Boiling Point: 2543K, 2270C, 4118F
Melting Point: 505.21K, 232.06C, 449.71F
Heat of Vaporization: 295.8 kJ/mol
Coefficient of Lineal Thermal Expansion/K-1: N/A
Electrical Conductivity: 0.0917 106/cm
Thermal Conductivity: 0.666 W/cmK
Density: 7.31 g/cm3 @ 300K
Enthalpy of Atomization: 301.3 kJ/mole @ 25C
Enthalpy of Fusion: 7.03 kJ/mole
Enthalpy of Vaporization: 290.4 kJ/mole
Flammability Class: Non-combustible solid (except as dust)
Molar Volume: 16.31 cm3/mole
Optical Refractive Index: unknown
Relative Gas Density (Air=1): unknown
Specific Heat: 0.227 J/gK
Vapor Pressure: 5.78E-21 Pa @ 232.06C
Estimated Crustal Abundance: 2.3 milligrams per kilogram
Estimated Oceanic Abundance: 410-6 milligrams per liter


(anglo-Saxon, tin; L. stannum) Known to the ancients. Tin is found chiefly in cassiterite (SnO2). Most of the world's supply comes from Malaya, Bolivia, Indonesia, Zaire, Thailand, and Nigeria. The U.S. produces almost none, although occurrences have been found in Alaska and California. Tin is obtained by reducing the ore with coal in a reverberatory furnace. Ordinary tin is composed of nine stable isotopes; 18 unstable isotopes are also known. Ordinary tin is a silver-white metal, is malleable, somewhat ductile, and has a highly crystalline structure. Due to the breaking of these crystals, a "tin cry" is heard when a bar is bent. The element has two allotropic forms at normal pressure. On warming, gray, or alpha tin, with a cubic structure, changes at 13.2oC into white, or beta tin, the ordinary form of the metal. White tin has a tetragonal structure. When tin is cooled below 13.2oC, it changes slowly from white to gray. This change is affected by impurities such as aluminum and zinc, and can be prevented by small additions of antimony or bismuth. This change from the alpha to beta form is called the tin pest. There are few if any uses for gray tin. Tin takes a high polish and is used to coat other metals to prevent corrosion or other chemical action. Such tin plate over steel is used in the so-called tin can for preserving food. Alloys of tin are very important. Soft solder, type metal, fusible metal, pewter, bronze, bell metal, Babbitt metal, White metal, die casting alloy, and phosphor bronze are some of the important alloys using tin. Tin resists distilled sea and soft tap water, but is attacked by strong acids, alkalis, and acid salts. Oxygen in solution accelerates the attack. When heated in air, tin forms SnO2, which is feebly acid, forming stannate salts with basic oxides. The most important salt is the chloride, which is used as a reducing agent and as a mordant in calico printing. Tin salts sprayed onto glass are used to produce electrically conductive coatings. These have been used for panel lighting and for frost-free windshields. Most window glass is now made by floating molten glass on molten tin (float glass) to produce a flat surface (Pilkington process). Of recent interest is a crystalline tin-niobium alloy that is superconductive at very low temperatures. This promises to be important in the construction of superconductive magnets that generate enormous field strengths but use practically no power. Such magnets, made of tin-niobium wire, weigh but a few pounds and produce magnetic fields that, when started with a small battery, are comparable to that of a 100 ton electromagnet operated continuously with a large power supply. The small amount of tin found in canned foods is quite harmless. The agreed limit of tin content in U.S. foods is 300 mg/kg. The trialkyl and triaryl tin compounds are used as biocides and must be handled carefully. Over the past 25 years the price of tin has varied from 50 cents/lb to its present price of about $4/lb. as of January 1990.

Source: CRC Handbook of Chemistry and Physics, 1913-1995. David R. Lide, Editor in Chief. Author: C.R. Hammond