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Tin is a
chemical element A chemical element is a species of atoms that have a given number of protons in their nuclei, including the pure substance consisting only of that species. Unlike chemical compounds, chemical elements cannot be broken down into simpler sub ...
with the symbol Sn (from la, stannum) and
atomic number The atomic number or nuclear charge number (symbol ''Z'') of a chemical element is the charge number of an atomic nucleus. For ordinary nuclei, this is equal to the proton number (''n''p) or the number of protons found in the nucleus of every ...
 50. Tin is 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. When bent, the so-called "
tin cry Tin cry is the characteristic sound heard when a bar made of tin is bent. Variously described as a "screaming" or "crackling" sound, the effect is caused by the crystal twinning in the metal. The sound is not particularly loud, despite terms lik ...
" can be heard as a result of twinning in tin crystals; this trait is shared by
indium Indium is a chemical element with the symbol In and atomic number 49. Indium is the softest metal that is not an alkali metal. It is a silvery-white metal that resembles tin in appearance. It is a post-transition metal that makes up 0.21 parts ...
,
cadmium Cadmium is a chemical element with the symbol Cd and atomic number 48. This soft, silvery-white metal is chemically similar to the two other stable metals in group 12, zinc and mercury. Like zinc, it demonstrates oxidation state +2 in most of ...
,
zinc Zinc is a chemical element with the symbol Zn and atomic number 30. Zinc is a slightly brittle metal at room temperature and has a shiny-greyish appearance when oxidation is removed. It is the first element in group 12 (IIB) of the periodi ...
, and mercury in the solid state. Pure tin after solidifying presents a mirror-like appearance similar to most metals. In most tin
alloy An alloy is a mixture of chemical elements of which at least one is a metal. Unlike chemical compounds with metallic bases, an alloy will retain all the properties of a metal in the resulting material, such as electrical conductivity, ductilit ...
s (such as
pewter Pewter () is a malleable metal alloy consisting of tin (85–99%), antimony (approximately 5–10%), copper (2%), bismuth, and sometimes silver. Copper and antimony (and in antiquity lead) act as hardeners, but lead may be used in lower grades ...
) the metal solidifies with a dull gray color. Tin is a
post-transition metal The metallic elements in the periodic table located between the transition metals and the chemically weak nonmetallic metalloids have received many names in the literature, such as ''post-transition metals'', ''poor metals'', ''other metals'', ...
in
group 14 The carbon group is a periodic table group consisting of carbon (C), silicon (Si), germanium (Ge), tin (Sn), lead (Pb), and flerovium (Fl). It lies within the p-block. In modern IUPAC notation, it is called group 14. In the field of semicon ...
of the
periodic table of elements The periodic table, also known as the periodic table of the (chemical) elements, is a rows and columns arrangement of the chemical elements. It is widely used in chemistry, physics, and other sciences, and is generally seen as an icon of c ...
. It is obtained chiefly from the
mineral In geology and mineralogy, a mineral or mineral species is, broadly speaking, a solid chemical compound with a fairly well-defined chemical composition and a specific crystal structure that occurs naturally in pure form.John P. Rafferty, ed. (2 ...
cassiterite, which contains stannic oxide, . Tin shows a chemical similarity to both of its neighbors in group 14, germanium and
lead Lead is a chemical element with the symbol Pb (from the Latin ) and atomic number 82. It is a heavy metal that is denser than most common materials. Lead is soft and malleable, and also has a relatively low melting point. When freshly cu ...
, and has two main
oxidation state In chemistry, the oxidation state, or oxidation number, is the hypothetical charge of an atom if all of its bonds to different atoms were fully ionic. It describes the degree of oxidation (loss of electrons) of an atom in a chemical compound. C ...
s, +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
isotope Isotopes are two or more types of atoms that have the same atomic number (number of protons in their nuclei) and position in the periodic table (and hence belong to the same chemical element), and that differ in nucleon numbers (mass numb ...
s in the periodic table, thanks to its magic number of protons. It has two main
allotropes Allotropy or allotropism () is the property of some chemical elements to exist in two or more different forms, in the same physical state, known as allotropes of the elements. Allotropes are different structural modifications of an element: th ...
: at room temperature, the stable allotrope is β-tin, a silvery-white,
malleable Ductility is a mechanical property commonly described as a material's amenability to drawing (e.g. into wire). In materials science, ductility is defined by the degree to which a material can sustain plastic deformation under tensile stres ...
metal; at low temperatures it is less dense grey α-tin, which has the
diamond cubic The diamond cubic crystal structure is a repeating pattern of 8 atoms that certain materials may adopt as they solidify. While the first known example was diamond, other elements in group 14 also adopt this structure, including α-tin, the se ...
structure. Metallic tin does not easily
oxidize Redox (reduction–oxidation, , ) is a type of chemical reaction in which the oxidation states of substrate change. Oxidation is the loss of electrons or an increase in the oxidation state, while reduction is the gain of electrons or a d ...
in air and water. The first tin alloy used on a large scale was bronze, made of  tin and  
copper Copper is a chemical element with the symbol Cu (from la, cuprum) and atomic number 29. It is a soft, malleable, and ductile metal with very high thermal and electrical conductivity. A freshly exposed surface of pure copper has a pinkis ...
, from as early as 3000 BC. After 600 BC, pure metallic tin was produced.
Pewter Pewter () is a malleable metal alloy consisting of tin (85–99%), antimony (approximately 5–10%), copper (2%), bismuth, and sometimes silver. Copper and antimony (and in antiquity lead) act as hardeners, but lead may be used in lower grades ...
, which is an alloy of 85–90% tin with the remainder commonly consisting of
copper Copper is a chemical element with the symbol Cu (from la, cuprum) and atomic number 29. It is a soft, malleable, and ductile metal with very high thermal and electrical conductivity. A freshly exposed surface of pure copper has a pinkis ...
,
antimony Antimony is a chemical element with the symbol Sb (from la, stibium) and atomic number 51. A lustrous gray metalloid, it is found in nature mainly as the sulfide mineral stibnite (Sb2S3). Antimony compounds have been known since ancient t ...
, bismuth, and sometimes lead and silver, has been used for flatware since the
Bronze Age The Bronze Age is a historic period, lasting approximately from 3300 BC to 1200 BC, characterized by the use of bronze, the presence of writing in some areas, and other early features of urban civilization. The Bronze Age is the second prin ...
. In modern times, tin is used in many alloys, most notably tin / lead soft
solder Solder (; NA: ) is a fusible metal alloy used to create a permanent bond between metal workpieces. Solder is melted in order to wet the parts of the joint, where it adheres to and connects the pieces after cooling. Metals or alloys suitable ...
s, which are typically 60% or more tin, and in the manufacture of transparent, electrically conducting films of
indium tin oxide Indium tin oxide (ITO) is a ternary composition of indium, tin and oxygen in varying proportions. Depending on the oxygen content, it can be described as either a ceramic or an alloy. Indium tin oxide is typically encountered as an oxygen-saturated ...
in
optoelectronic Optoelectronics (or optronics) is the study and application of electronic devices and systems that find, detect and control light, usually considered a sub-field of photonics. In this context, ''light'' often includes invisible forms of radiat ...
applications. Another large application is
corrosion Corrosion is a natural process that converts a refined metal into a more chemically stable oxide. It is the gradual deterioration of materials (usually a metal) by chemical or electrochemical reaction with their environment. Corrosion engi ...
-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 A steel can, tin can, tin (especially in British English, Australian English, Canadian English and South African English), steel packaging, or can is a container for the distribution or storage of goods, made of thin metal. Many cans ...
. Some
organotin compounds Organotin compounds or stannanes are chemical compounds based on tin with hydrocarbon substituents. Organotin chemistry is part of the wider field of organometallic chemistry. The first organotin compound was diethyltin diiodide (), discovered ...
can be extremely toxic.


Characteristics


Physical

Tin is a soft,
malleable Ductility is a mechanical property commonly described as a material's amenability to drawing (e.g. into wire). In materials science, ductility is defined by the degree to which a material can sustain plastic deformation under tensile stres ...
,
ductile Ductility is a mechanical property commonly described as a material's amenability to drawing (e.g. into wire). In materials science, ductility is defined by the degree to which a material can sustain plastic deformation under tensile stres ...
and highly
crystal A crystal or crystalline solid is a solid material whose constituents (such as atoms, molecules, or ions) are arranged in a highly ordered microscopic structure, forming a crystal lattice that extends in all directions. In addition, macro ...
line silvery-white
metal A metal (from Greek μέταλλον ''métallon'', "mine, quarry, metal") is a material that, when freshly prepared, polished, or fractured, shows a lustrous appearance, and conducts electricity and heat relatively well. Metals are typicall ...
. When a bar of tin is bent a crackling sound known as the "
tin cry Tin cry is the characteristic sound heard when a bar made of tin is bent. Variously described as a "screaming" or "crackling" sound, the effect is caused by the crystal twinning in the metal. The sound is not particularly loud, despite terms lik ...
" can be heard from the twinning of the crystals. Tin melts at about the lowest in group 14. The melting point is further lowered to for 11 nm particles. β-tin, the metallic form or white tin, has BCT structure and is stable at and above room temperature and is malleable. α-tin, the nonmetallic form or gray tin, is stable below and is
brittle A material is brittle if, when subjected to stress, it fractures with little elastic deformation and without significant plastic deformation. Brittle materials absorb relatively little energy prior to fracture, even those of high strength. Br ...
. α-tin has a
diamond cubic The diamond cubic crystal structure is a repeating pattern of 8 atoms that certain materials may adopt as they solidify. While the first known example was diamond, other elements in group 14 also adopt this structure, including α-tin, the se ...
crystal structure In crystallography, crystal structure is a description of the ordered arrangement of atoms, ions or molecules in a crystalline material. Ordered structures occur from the intrinsic nature of the constituent particles to form symmetric patterns ...
, similar to
diamond Diamond is a solid form of the element carbon with its atoms arranged in a crystal structure called diamond cubic. Another solid form of carbon known as graphite is the chemically stable form of carbon at room temperature and pressure, ...
,
silicon Silicon is a chemical element with the symbol Si and atomic number 14. It is a hard, brittle crystalline solid with a blue-grey metallic luster, and is a tetravalent metalloid and semiconductor. It is a member of group 14 in the periodic ta ...
or germanium. α-tin has no metallic properties, because its atoms form a
covalent A covalent bond is a chemical bond that involves the sharing of electrons to form electron pairs between atoms. These electron pairs are known as shared pairs or bonding pairs. The stable balance of attractive and repulsive forces between atoms ...
structure in which electrons cannot move freely. α-tin is a dull-gray powdery material with no common uses other than specialized
semiconductor A semiconductor is a material which has an electrical conductivity value falling between that of a conductor, such as copper, and an insulator, such as glass. Its resistivity falls as its temperature rises; metals behave in the opposite way. ...
applications. γ-tin and σ-tin exist at temperatures above   and pressures above several
GPa Grading in education is the process of applying standardized measurements for varying levels of achievements in a course. Grades can be assigned as letters (usually A through F), as a range (for example, 1 to 6), as a percentage, or as a numbe ...
. In cold conditions β-tin tends to transform spontaneously into α-tin, a phenomenon known as "
tin pest Tin is a chemical element with the symbol Sn (from la, stannum) and atomic number 50. Tin is 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. When bent, t ...
" or "tin disease". Some unverifiable sources also say that, during
Napoleon Napoleon Bonaparte ; it, Napoleone Bonaparte, ; co, Napulione Buonaparte. (born Napoleone Buonaparte; 15 August 1769 – 5 May 1821), later known by his regnal name Napoleon I, was a French military commander and political leader who ...
'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. The α-β transformation temperature is , but impurities (e.g. Al, Zn, etc.) lower it well below . With the addition of
antimony Antimony is a chemical element with the symbol Sb (from la, stibium) and atomic number 51. A lustrous gray metalloid, it is found in nature mainly as the sulfide mineral stibnite (Sb2S3). Antimony compounds have been known since ancient t ...
or
bismuth Bismuth is a chemical element with the symbol Bi and atomic number 83. It is a post-transition metal and one of the pnictogens, with chemical properties resembling its lighter group 15 siblings arsenic and antimony. Elemental bismuth occurs ...
the transformation might not occur at all, increasing durability. Commercial 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. Alloying elements such as copper, antimony, bismuth, cadmium, and silver increase the hardness of tin. Tin easily forms hard, brittle intermetallic phases that are typically undesirable. It does not mix into a solution with most metals and elements so tin does not have much solid solubility. Tin mixes well with
bismuth Bismuth is a chemical element with the symbol Bi and atomic number 83. It is a post-transition metal and one of the pnictogens, with chemical properties resembling its lighter group 15 siblings arsenic and antimony. Elemental bismuth occurs ...
, gallium,
lead Lead is a chemical element with the symbol Pb (from the Latin ) and atomic number 82. It is a heavy metal that is denser than most common materials. Lead is soft and malleable, and also has a relatively low melting point. When freshly cu ...
,
thallium Thallium is a chemical element with the symbol Tl and atomic number 81. It is a gray post-transition metal that is not found free in nature. When isolated, thallium resembles tin, but discolors when exposed to air. Chemists William Crookes an ...
and
zinc Zinc is a chemical element with the symbol Zn and atomic number 30. Zinc is a slightly brittle metal at room temperature and has a shiny-greyish appearance when oxidation is removed. It is the first element in group 12 (IIB) of the periodi ...
forming simple eutectic systems. Tin becomes a superconductor below 3.72  K and was one of the first superconductors to be studied. The
Meissner effect The Meissner effect (or Meissner–Ochsenfeld effect) is the expulsion of a magnetic field from a superconductor during its transition to the superconducting state when it is cooled below the critical temperature. This expulsion will repel a ne ...
, one of the characteristic features of superconductors, was first discovered in superconducting tin crystals.


Chemical

Tin resists corrosion from
water Water (chemical formula ) is an Inorganic compound, inorganic, transparent, tasteless, odorless, and Color of water, nearly colorless chemical substance, which is the main constituent of Earth's hydrosphere and the fluids of all known living ...
, but can be corroded by acids and alkalis. Tin can be highly polished and is used as a protective coat for other metals, a protective oxide ( passivation) layer prevents further oxidation. Tin acts as a
catalyst Catalysis () is the process of increasing the rate of a chemical reaction by adding a substance known as a catalyst (). Catalysts are not consumed in the reaction and remain unchanged after it. If the reaction is rapid and the catalyst recyc ...
triggering a chemical reaction of a solution containing
oxygen Oxygen is the chemical element with the symbol O and atomic number 8. It is a member of the chalcogen group in the periodic table, a highly reactive nonmetal, and an oxidizing agent that readily forms oxides with most elements as ...
and helps to increase the speed of the chemical reaction that results.


Isotopes

Tin has ten stable isotopes, the
greatest number Greatest may refer to: * ''Greatest!'', a 1959 album by Johnny Cash * ''Bee Gees Greatest'', a 1979 album by Bee Gees * ''Greatest'' (The Go-Go's album), 1990 * ''Greatest'' (Duran Duran album), 1998 * Greatest (song), a song by Eminem * "Greate ...
of any element. The isotopes of tin have atomic masses of 112, 114, 115, 116, 117, 118, 119, 120, 122, and 124. 120Sn makes up almost a third of all tin; 118Sn, and 116Sn are also common, while 115Sn is the least common stable isotope. The isotopes with even
mass number The mass number (symbol ''A'', from the German word ''Atomgewicht'' tomic weight, also called atomic mass number or nucleon number, is the total number of protons and neutrons (together known as nucleons) in an atomic nucleus. It is approxima ...
s have no nuclear spin, while those with odd mass numbers have a spin of 1/2. Tin is among the easiest elements to detect and analyze by
NMR spectroscopy Nuclear magnetic resonance spectroscopy, most commonly known as NMR spectroscopy or magnetic resonance spectroscopy (MRS), is a spectroscopic technique to observe local magnetic fields around atomic nuclei. The sample is placed in a magnetic fie ...
which relies on molecular weight and its
chemical shift In nuclear magnetic resonance (NMR) spectroscopy, the chemical shift is the resonant frequency of an atomic nucleus relative to a standard in a magnetic field. Often the position and number of chemical shifts are diagnostic of the structure o ...
s are referenced against .Only H, F, P, Tl and Xe are easier to use NMR analysis with for samples containing isotopes at their natural abundance. The large number of stable isotopes is thought to be a direct result of tin having the
atomic number The atomic number or nuclear charge number (symbol ''Z'') of a chemical element is the charge number of an atomic nucleus. For ordinary nuclei, this is equal to the proton number (''n''p) or the number of protons found in the nucleus of every ...
50, a " magic number" in nuclear physics. Of the stable isotopes Tin-115 has a high capture cross section for fast neutron energies at 30 Barns. Two other isotopes Tin-117 ranks next with a cross section of 2.3 Barn while isotope Tin-119 has a slightly smaller cross section of 2.2 Barn. Before these cross sections were well known it was proposed to use Tin-Lead solder as a reactor coolant for fast reactors because of its low melting point. Current studies are for Lead or Lead-Bismuth reactor coolants because both heavy metals are nearly transparent to fast neutrons with very low capture cross sections. In order to use a Tin or Tin-Lead coolant the Tin would first have to go through isotopes separation to remove the 115, 117 and 119 isotopes from the material. Combined these three isotopes make up about 17% of the entire mass of natural Tin but represent nearly all of the capture cross section. Of the remaining seven isotopes Tin-112 has a capture cross section of 1 Barn. The other six isotopes forming 82.7% of all Tin have capture cross sections of 0.3 Barn or less making them effectively transparent to neutrons like Lead and Bismuth. Tin has 31 unstable isotopes, ranging in mass number from 99 to 139. The unstable tin isotopes have a half-life of less than a year except 126Sn which has a
half-life Half-life (symbol ) is the time required for a quantity (of substance) to reduce to half of its initial value. The term is commonly used in nuclear physics to describe how quickly unstable atoms undergo radioactive decay or how long stable at ...
of 230,000 years. 100Sn and 132Sn are two of the few nuclides with a "
doubly magic In nuclear physics, a magic number is a number of nucleons (either protons or neutrons, separately) such that they are arranged into complete shells within the atomic nucleus. As a result, atomic nuclei with a 'magic' number of protons or neutron ...
" nucleus which despite being unstable, as they have very uneven neutron–proton ratios, are the endpoints beyond which tin isotopes lighter than 100Sn and heavier than 132Sn are much less stable. Another 30 metastable isomers have been identified for tin isotopes between 111 and 131, the most stable being 121mSn, with a half-life of 43.9 years. The relative differences in the number of tin's stable isotopes can be explained by how they are formed during stellar nucleosynthesis. 116Sn through 120Sn are formed in the ''s''-process (slow neutron capture) in most stars which leads to them being the most common tin isotopes, while 122Sn and 124Sn are only formed in the ''r''-process (rapid neutron capture) in supernovae and are less common. Tin isotopes 117Sn through 120Sn are also produced in the ''r''-process. 112Sn, 114Sn, and 115Sn, cannot be made in significant amounts in the ''s''- or ''r''-processes and are among the
p-nuclei p-nuclei (''p'' stands for proton-rich) are certain proton-rich, naturally occurring isotopes of some elements between selenium and mercury inclusive which cannot be produced in either the s- or the r-process. Definition The classical, gro ...
whose origins are not well understood. Some ideas about for their formation include
proton capture Proton capture is a nuclear reaction in which an atomic nucleus and one or more protons collide and merge to form a heavier nucleus. Since protons have positive electric charge, they are repelled electrostatically by the positively charged nucl ...
and
photodisintegration Photodisintegration (also called phototransmutation, or a photonuclear reaction) is a nuclear process in which an atomic nucleus absorbs a high-energy gamma ray, enters an excited state, and immediately decays by emitting a subatomic particle. The ...
, 115Sn might be partially produced in the ''s''-process both directly and as the daughter of long-lived 115In.


Etymology

The word ''tin'' is shared among
Germanic languages The Germanic languages are a branch of the Indo-European language family spoken natively by a population of about 515 million people mainly in Europe, North America, Oceania and Southern Africa. The most widely spoken Germanic language, E ...
and can be traced back to reconstructed
Proto-Germanic Proto-Germanic (abbreviated PGmc; also called Common Germanic) is the reconstructed proto-language of the Germanic branch of the Indo-European languages. Proto-Germanic eventually developed from pre-Proto-Germanic into three Germanic bran ...
; cognates include
German German(s) may refer to: * Germany (of or related to) ** Germania (historical use) * Germans, citizens of Germany, people of German ancestry, or native speakers of the German language ** For citizens of Germany, see also German nationality law **Ge ...
,
Swedish Swedish or ' may refer to: Anything from or related to Sweden, a country in Northern Europe. Or, specifically: * Swedish language, a North Germanic language spoken primarily in Sweden and Finland ** Swedish alphabet, the official alphabet used by ...
and
Dutch Dutch commonly refers to: * Something of, from, or related to the Netherlands * Dutch people () * Dutch language () Dutch may also refer to: Places * Dutch, West Virginia, a community in the United States * Pennsylvania Dutch Country People E ...
. It is not found in other branches of
Indo-European The Indo-European languages are a language family native to the overwhelming majority of Europe, the Iranian plateau, and the northern Indian subcontinent. Some European languages of this family, English, French, Portuguese, Russian, Dutc ...
, except by borrowing from Germanic (e.g.,
Irish Irish may refer to: Common meanings * Someone or something of, from, or related to: ** Ireland, an island situated off the north-western coast of continental Europe ***Éire, Irish language name for the isle ** Northern Ireland, a constituent unit ...
from English). The
Latin Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through the power of the ...
name for tin, , originally meant an alloy of silver and lead, and came to mean 'tin' in the fourth century—the earlier Latin word for it was , or "white lead". apparently came from an earlier (meaning the same substance), the origin of the
Romance Romance (from Vulgar Latin , "in the Roman language", i.e., "Latin") may refer to: Common meanings * Romance (love), emotional attraction towards another person and the courtship behaviors undertaken to express the feelings * Romance languages, ...
and Celtic terms for ''tin'', such as French ,
Spanish Spanish might refer to: * Items from or related to Spain: **Spaniards are a nation and ethnic group indigenous to Spain **Spanish language, spoken in Spain and many Latin American countries **Spanish cuisine Other places * Spanish, Ontario, Can ...
,
Italian Italian(s) may refer to: * Anything of, from, or related to the people of Italy over the centuries ** Italians, an ethnic group or simply a citizen of the Italian Republic or Italian Kingdom ** Italian language, a Romance language *** Regional Ita ...
, and
Irish Irish may refer to: Common meanings * Someone or something of, from, or related to: ** Ireland, an island situated off the north-western coast of continental Europe ***Éire, Irish language name for the isle ** Northern Ireland, a constituent unit ...
. The origin of / is unknown; it may be pre-
Indo-European The Indo-European languages are a language family native to the overwhelming majority of Europe, the Iranian plateau, and the northern Indian subcontinent. Some European languages of this family, English, French, Portuguese, Russian, Dutc ...
. The suggests instead that came from Cornish , and is evidence that
Cornwall Cornwall (; kw, Kernow ) is a historic county and ceremonial county in South West England. It is recognised as one of the Celtic nations, and is the homeland of the Cornish people. Cornwall is bordered to the north and west by the Atlantic ...
in the first centuries AD was the main source of tin.


History

Tin extraction and use can be dated to the beginnings of the Bronze Age around 3000 BC, when it was observed that
copper Copper is a chemical element with the symbol Cu (from la, cuprum) and atomic number 29. It is a soft, malleable, and ductile metal with very high thermal and electrical conductivity. A freshly exposed surface of pure copper has a pinkis ...
objects formed of
polymetallic In chemistry or mining, polymetal or polymetallic is a substance composed of a combination of different metals. When the substance contains only two metals the term '' bimetal'' (''bimetallic'') is sometimes preferred. A (or ') is an ore that ...
ores with different metal contents had different physical properties. The earliest bronze objects had a tin or arsenic content of less than 2% and are believed to be the result of unintentional
alloying An alloy is a mixture of chemical elements of which at least one is a metal. Unlike chemical compounds with metallic bases, an alloy will retain all the properties of a metal in the resulting material, such as electrical conductivity, ductility ...
due to trace metal content in the copper ore. The addition of a second metal to copper increases its hardness, lowers the melting temperature, and improves the
casting Casting is a manufacturing process in which a liquid material is usually poured into a mold, which contains a hollow cavity of the desired shape, and then allowed to solidify. The solidified part is also known as a ''casting'', which is ejected ...
process by producing a more fluid melt that cools to a denser, less spongy metal. This was an important innovation that allowed for the much more complex shapes cast in closed molds of the Bronze Age.
Arsenical bronze Arsenical bronze is an alloy in which arsenic, as opposed to or in addition to tin or other constituent metals, is combined with copper to make bronze. The use of arsenic with copper, either as the secondary constituent or with another component ...
objects appear first in the Near East where arsenic is commonly found with copper ore, but the health risks were quickly realized and the quest for sources of the much less hazardous tin ores began early in the Bronze Age. This created the demand for rare tin metal and formed a trade network that linked the distant sources of tin to the markets of Bronze Age cultures. Cassiterite (), the oxide form of tin, was most likely the original source of tin. Other tin ores are less common sulfides such as stannite that require a more involved
smelting Smelting is a process of applying heat to ore, to extract a base metal. It is a form of extractive metallurgy. It is used to extract many metals from their ores, including silver, iron, copper, and other base metals. Smelting uses heat and a ...
process. Cassiterite often accumulates in
alluvial Alluvium (from Latin ''alluvius'', from ''alluere'' 'to wash against') is loose clay, silt, sand, or gravel that has been deposited by running water in a stream bed, on a floodplain, in an alluvial fan or beach, or in similar settings. All ...
channels as placer deposits because it is harder, heavier, and more chemically resistant than the accompanying
granite Granite () is a coarse-grained ( phaneritic) intrusive igneous rock composed mostly of quartz, alkali feldspar, and plagioclase. It forms from magma with a high content of silica and alkali metal oxides that slowly cools and solidifies under ...
. Cassiterite is usually black or dark in color, and these deposits can be easily seen in
river banks In geography, a bank is the land alongside a body of water. Different structures are referred to as ''banks'' in different fields of geography, as follows. In limnology (the study of inland waters), a stream bank or river bank is the terrai ...
. Alluvial ( placer) deposits may incidentally have been collected and separated by methods similar to
gold panning Gold panning, or simply ''panning'', is a form of placer mining and traditional mining that extracts gold from a placer deposit using a pan. The process is one of the simplest ways to extract gold, and is popular with geology enthusiasts especi ...
.


Compounds and chemistry

In the great majority of its compounds, tin has the
oxidation state In chemistry, the oxidation state, or oxidation number, is the hypothetical charge of an atom if all of its bonds to different atoms were fully ionic. It describes the degree of oxidation (loss of electrons) of an atom in a chemical compound. C ...
II or IV. Compounds containing
bivalent Bivalent may refer to: * Bivalent (chemistry), a molecule formed from two or more atoms bound together *Bivalent (engine), an engine that can operate on two different types of fuel *Bivalent (genetics), a pair of homologous chromosomes *Bivalent log ...
tin are called while those containing
tetravalent In chemistry, the valence (US spelling) or valency (British spelling) of an element is the measure of its combining capacity with other atoms when it forms chemical compounds or molecules. Description The combining capacity, or affinity of an ...
tin are termed .


Inorganic compounds

Halide compounds are known for both oxidation states. For Sn(IV), all four halides are well known: SnF4, SnCl4, SnBr4, and SnI4. The three heavier members are volatile molecular compounds, whereas the tetrafluoride is polymeric. All four halides are known for Sn(II) also: SnF2, , SnBr2, and SnI2. All are polymeric solids. Of these eight compounds, only the iodides are colored.
Tin(II) chloride Tin(II) chloride, also known as stannous chloride, is a white crystalline solid with the formula . It forms a stable dihydrate, but aqueous solutions tend to undergo hydrolysis, particularly if hot. SnCl2 is widely used as a reducing agent (in aci ...
(also known as stannous chloride) is the most important commercial tin halide. Illustrating the routes to such compounds,
chlorine Chlorine is a chemical element with the symbol Cl and atomic number 17. The second-lightest of the halogens, it appears between fluorine and bromine in the periodic table and its properties are mostly intermediate between them. Chlorine i ...
reacts with tin metal to give SnCl4 whereas the reaction of hydrochloric acid and tin produces and hydrogen gas. Alternatively SnCl4 and Sn combine to stannous chloride by a process called
comproportionation Comproportionation or synproportionation is a chemical reaction where two reactants containing the same element but with different oxidation numbers, form a compound having an intermediate oxidation number. It is the opposite of disproportionation. ...
: :SnCl4 + Sn → 2 Tin can form many oxides, sulfides, and other
chalcogenide : 220px, Cadmium sulfide, a prototypical metal chalcogenide, is used as a yellow pigment. A chalcogenide is a chemical compound consisting of at least one chalcogen anion and at least one more electropositive element. Although all group 16 elements ...
derivatives. The dioxide (cassiterite) forms when tin is heated in the presence of
air The atmosphere of Earth is the layer of gases, known collectively as air, retained by Earth's gravity that surrounds the planet and forms its planetary atmosphere. The atmosphere of Earth protects life on Earth by creating pressure allowing f ...
. is
amphoteric In chemistry, an amphoteric compound () is a molecule or ion that can react both as an acid and as a base. What exactly this can mean depends on which definitions of acids and bases are being used. One type of amphoteric species are amphipro ...
, which means that it dissolves in both acidic and basic solutions. Stannates with the structure []2−, like [], are also known, though the free stannic acid [] is unknown. Sulfides of tin exist in both the +2 and +4 oxidation states: tin(II) sulfide and tin(IV) sulfide ([ osaic gold).


Hydrides

Stannane Stannane or tin hydride is an inorganic compound with the chemical formula . It is a colourless gas and the tin analogue of methane. Stannane can be prepared by the reaction of and . : Stannane decomposes slowly at room temperature to give ...
(), with tin in the +4 oxidation state, is unstable. Organotin hydrides are however well known, e.g.
tributyltin hydride Tributyltin hydride is an organotin compound with the formula (C4H9)3SnH. It is a colorless liquid that is soluble in organic solvents. The compound is used as a source of hydrogen atoms in organic synthesis. Synthesis and characterization The c ...
(Sn(C4H9)3H). These compound release transient tributyl tin radicals, which are rare examples of compounds of tin(III).


Organotin compounds

Organotin compounds, sometimes called stannanes, are
chemical compounds A chemical compound is a chemical substance composed of many identical molecules (or molecular entities) containing atoms from more than one chemical element held together by chemical bonds. A molecule consisting of atoms of only one element ...
with tin–carbon bonds. Of the tin compounds, the organic derivatives are commercially the most useful. Some organotin compounds are highly toxic and have been used as biocides. The first organotin compound to be reported was diethyltin diiodide ((C2H5)2SnI2), reported by
Edward Frankland Sir Edward Frankland, (18 January 18259 August 1899) was an English chemist. He was one of the originators of organometallic chemistry and introduced the concept of combining power or valence. An expert in water quality and analysis, he was ...
in 1849. Most organotin compounds are colorless liquids or solids that are stable to air and water. They adopt tetrahedral geometry. Tetraalkyl- and tetraaryltin compounds can be prepared using Grignard reagents: : + 4 RMgBr → + 4 MgBrCl The mixed halide-alkyls, which are more common and more important commercially than the tetraorgano derivatives, are prepared by redistribution reactions: : + → 2 R2 Divalent organotin compounds are uncommon, although more common than related divalent
organogermanium Organogermanium compounds are organometallic compounds containing a carbon to germanium or hydrogen to germanium chemical bond. Organogermanium chemistry is the corresponding chemical science. Germanium shares group 14 in the periodic table with s ...
and organosilicon compounds. The greater stabilization enjoyed by Sn(II) is attributed to the "
inert pair effect The inert-pair effect is the tendency of the two electrons in the outermost atomic ''s''-orbital to remain unshared in compounds of post-transition metals. The term ''inert-pair effect'' is often used in relation to the increasing stability of ox ...
". Organotin(II) compounds include both stannylenes (formula: R2Sn, as seen for singlet
carbene In organic chemistry, a carbene is a molecule containing a neutral carbon atom with a valence of two and two unshared valence electrons. The general formula is or where the R represents substituents or hydrogen atoms. The term "carbene" ma ...
s) and distannylenes (R4Sn2), which are roughly equivalent to
alkene In organic chemistry, an alkene is a hydrocarbon containing a carbon–carbon double bond. Alkene is often used as synonym of olefin, that is, any hydrocarbon containing one or more double bonds.H. Stephen Stoker (2015): General, Organic, an ...
s. Both classes exhibit unusual reactions.


Occurrence

Tin is generated via the long ''s''-process in low-to-medium mass stars (with masses of 0.6 to 10 times that of the
Sun The Sun is the star at the center of the Solar System. It is a nearly perfect ball of hot plasma, heated to incandescence by nuclear fusion reactions in its core. The Sun radiates this energy mainly as light, ultraviolet, and infrared radi ...
), and finally by
beta decay In nuclear physics, beta decay (β-decay) is a type of radioactive decay in which a beta particle (fast energetic electron or positron) is emitted from an atomic nucleus, transforming the original nuclide to an isobar of that nuclide. For ...
of the heavy isotopes of
indium Indium is a chemical element with the symbol In and atomic number 49. Indium is the softest metal that is not an alkali metal. It is a silvery-white metal that resembles tin in appearance. It is a post-transition metal that makes up 0.21 parts ...
. Tin is the 49th most abundant element in Earth's crust, representing 2 part per million, ppm compared with 75 ppm for zinc, 50 ppm for copper, and 14 ppm for lead. Tin does not occur as the native element but must be extracted from various ores. Cassiterite () is the only commercially important source of tin, although small quantities of tin are recovered from complex sulfides such as stannite, cylindrite, franckeite, canfieldite, and teallite. Minerals with tin are almost always associated with
granite Granite () is a coarse-grained ( phaneritic) intrusive igneous rock composed mostly of quartz, alkali feldspar, and plagioclase. It forms from magma with a high content of silica and alkali metal oxides that slowly cools and solidifies under ...
rock, usually at a level of 1% tin oxide content. Because of the higher specific gravity of tin dioxide, about 80% of mined tin is from secondary deposits found downstream from the primary lodes. Tin is often recovered from granules washed downstream in the past and deposited in valleys or the sea. The most economical ways of mining tin are by dredging, Hydraulic mining, hydraulicking, or open cast mining, open pits. Most of the world's tin is produced from placer mining, placer deposits, which can contain as little as 0.015% tin. About 253,000 tonnes of tin were mined in 2011, mostly in China (110,000 t), Indonesia (51,000 t), Peru (34,600 t), Bolivia (20,700 t) and Brazil (12,000 t). Estimates of tin production have historically varied with the market and mining technology. It is estimated that, at current consumption rates and technologies, the Earth will run out of mine-able tin in 40 years. In 2006 Lester R. Brown, Lester Brown suggested tin could run out within 20 years based on conservative estimates of 2% annual growth. Scrap tin is an important source of the metal. Recovery of tin through recycling is increasing rapidly. Whereas the United States has neither mined (since 1993) nor smelted (since 1989) tin, it was the largest secondary producer, recycling nearly 14,000 tonnes in 2006. New deposits are reported in Mongolia, and in 2009, new deposits of tin were discovered in Colombia.


Production

Tin is produced by carbothermic reduction of the oxide ore with carbon or coke. Both reverberatory furnace and Electric arc furnace, electric furnace can be used.


Mining and smelting


Industry

The ten largest companies produced most of the world's tin in 2007. Most of the world's tin is traded on LME, from 8 countries, under 17 brands. International Tin Council was established in 1947 to control the price of tin. It collapsed in 1985. In 1984, ''Association of Tin Producing Countries'' was created, with Australia, Bolivia, Indonesia, Malaysia, Nigeria, Thailand, and Zaire as members.


Price and exchanges

Tin is unique among mineral commodities because of the complex agreements between producer countries and consumer countries dating back to 1921. Earlier agreements tended to be somewhat informal and led to the "First International Tin Agreement" in 1956, the first of a series that effectively collapsed in 1985. Through these agreements, the International Tin Council (ITC) had a considerable effect on tin prices. ITC supported the price of tin during periods of low prices by buying tin for its buffer stockpile and was able to restrain the price during periods of high prices by selling from the stockpile. This was an anti-free-market approach, designed to assure a sufficient flow of tin to consumer countries and a profit for producer countries. However, the buffer stockpile was not sufficiently large, and during most of those 29 years tin prices rose, sometimes sharply, especially from 1973 through 1980 when rampant inflation plagued many world economies. During the late 1970s and early 1980s, the U.S. reduced its strategic tin stockpile, partly to take advantage of historically high tin prices. The Early 1980s recession, 1981–82 recession damaged the tin industry. Tin consumption declined dramatically. ITC was able to avoid truly steep declines through accelerated buying for its buffer stockpile; this activity required extensive borrowing. ITC continued to borrow until late 1985 when it reached its credit limit. Immediately, a major "tin crisis" ensued — tin was delisted from trading on the London Metal Exchange for about three years. ITC dissolved soon afterward, and the price of tin, now in a free-market environment, fell to $4 per pound and remained around that level through the 1990s. The price increased again by 2010 with a rebound in consumption following the Financial crisis of 2007–2008, 2007–2008 economic crisis, accompanying restocking and continued growth in consumption. London Metal Exchange (LME) is tin's principal trading site. Other tin contract markets are Kuala Lumpur Tin Market (KLTM) and INATIN, Indonesia Tin Exchange (INATIN). Due to factors involved in the 2021 global supply chain crisis, tin prices almost doubled between 2020—21 and have had their largest annual rise in over 30 years. The International Tin Association estimated that global refined tin consumption will grow 7.2 percent in 2021, after losing 1.6 percent in 2020 as the COVID-19 pandemic disrupted global manufacturing industries.


Applications

In 2018, just under half of all tin produced was used in solder. The rest was divided between tin plating, tin chemicals, brass and bronze alloys, and niche uses.


Solder

Tin has long been used in alloys with lead as
solder Solder (; NA: ) is a fusible metal alloy used to create a permanent bond between metal workpieces. Solder is melted in order to wet the parts of the joint, where it adheres to and connects the pieces after cooling. Metals or alloys suitable ...
, in amounts of 5 to 70% w/w. Tin with lead forms a eutectic system, eutectic mixture at the weight proportion of 61.9% tin and 38.1% lead (the atomic proportion: 73.9% tin and 26.1% lead), with melting temperature of 183 °C (361.4 °F). Such solders are primarily used for joining plumbing, pipes or electric circuits. Since the European Union Waste Electrical and Electronic Equipment Directive (WEEE Directive) and Restriction of Hazardous Substances Directive came into effect on 1 July 2006, the lead content in such alloys has decreased. While lead exposure is associated with Lead poisoning, serious health problems, lead-free solder is not without its challenges, including a higher melting point, and the formation of Whisker (metallurgy), tin whiskers that cause electrical problems. Tin pest can occur in lead-free solders, leading to loss of the soldered joint. Replacement alloys are being found, but the problems of joint integrity remain.


Tin plating

Tin bonds readily to iron and is used for coating
lead Lead is a chemical element with the symbol Pb (from the Latin ) and atomic number 82. It is a heavy metal that is denser than most common materials. Lead is soft and malleable, and also has a relatively low melting point. When freshly cu ...
, zinc, and steel to prevent corrosion. Tin plating, Tin-plated (or tinning) steel containers is widely used for food preservation, and this forms a large part of the market for metallic tin. A tinplate canister for preserving food was first manufactured in London in 1812. Speakers of British English call such containers "tins", while speakers of American English call them "tin cans, cans" or "tin cans". One derivation of such use is the slang term "tinnie" or "tinny", meaning "can of beer" in Australia. The tin whistle is so called because it was mass-produced first in tin-plated steel. Copper cooking vessels such as saucepans and frying pans are frequently lined with a thin plating of tin, by electroplating or by Kalai (process), traditional chemical methods, since use of Copper toxicity, copper cookware with acidic foods can be toxic.


Specialized alloys

Tin in combination with other elements forms a wide variety of useful alloys. Tin is most commonly alloyed with copper.
Pewter Pewter () is a malleable metal alloy consisting of tin (85–99%), antimony (approximately 5–10%), copper (2%), bismuth, and sometimes silver. Copper and antimony (and in antiquity lead) act as hardeners, but lead may be used in lower grades ...
is 85–99% tin; Babbitt metal, bearing metal has a high percentage of tin as well. Bronze is mostly copper with 12% tin, while the addition of phosphorus yields phosphor bronze. Bell metal is also a copper–tin alloy, containing 22% tin. Tin has sometimes been used in coinage; it once formed a single-digit percentage (usually five percent or less) of American and Canadian pennies. Because copper is often the major metal in such coins, sometimes including zinc, these could be called bronze, or brass alloys. The niobium–tin compound Niobium–tin, Nb3Sn is commercially used in Electromagnetic coil, coils of superconducting magnets for its high critical temperature#In Superconductivity, critical temperature (18 K) and critical magnetic field (25 Tesla (unit), T). A superconducting magnet weighing as little as two kilograms is capable of producing the magnetic field of a conventional electromagnet weighing tons. A small percentage of tin is added to zirconium alloys for the cladding of nuclear fuel. Most metal pipes in a pipe organ are of a tin/lead alloy, with 50/50 as the most common composition. The proportion of tin in the pipe defines the pipe's tone, since tin has a desirable tonal resonance. When a tin/lead alloy cools, the lead phase solidifies first, then when the eutectic temperature is reached, the remaining liquid forms the layered tin/lead eutectic structure, which is shiny; contrast with the lead phase produces a mottled or spotted effect. This metal alloy is referred to as spotted metal. Major advantages of using tin for pipes include its appearance, workability, and resistance to corrosion.


Optoelectronics

The Indium tin oxide, oxides of indium and tin are electrically conductive and transparent, and are used to make transparent electrically conducting films with applications in optoelectronics devices such as liquid crystal displays.


Other applications

Punched tin-plated steel, also called pierced tin, is an artisan technique originating in central Europe for creating functional and decorative housewares. Decorative piercing designs exist in a wide variety, based on local tradition and the artisan. Punched tin lanterns are the most common application of this artisan technique. The light of a candle shining through the pierced design creates a decorative light pattern in the room where it sits. Lanterns and other punched tin articles were created in the New World from the earliest European settlement. A well-known example is the Revere lantern, named after Paul Revere. Before the modern era, in some areas of the Alps, a goat or sheep's horn would be sharpened and a tin panel would be punched out using the alphabet and numbers from one to nine. This learning tool was known appropriately as "the horn". Modern reproductions are decorated with such motifs as hearts and tulips. In America, pie safes and food safes were in use in the days before refrigeration. These were wooden cupboards of various styles and sizes – either floor standing or hanging cupboards meant to discourage vermin and insects and to keep dust from perishable foodstuffs. These cabinets had tinplate inserts in the doors and sometimes in the sides, punched out by the homeowner, cabinetmaker, or a tinsmith in varying designs to allow for air circulation while excluding flies. Modern reproductions of these articles remain popular in North America. Window glass is most often made by floating molten glass on molten tin (float glass), resulting in a flat and flawless surface. This is also called the "Pilkington process". Tin is used as a negative electrode in advanced Lithium-ion battery, Li-ion batteries. Its application is somewhat limited by the fact that some tin surfaces catalyze decomposition of carbonate-based electrolytes used in Li-ion batteries. Tin(II) fluoride is added to some dental care products as stannous fluoride (SnF2). Tin(II) fluoride can be mixed with calcium abrasives while the more common sodium fluoride gradually becomes biologically inactive in the presence of calcium compounds. It has also been shown to be more effective than sodium fluoride in controlling gingivitis. Tin is used as a target to create laser-induced Plasma (physics), plasmas that act as the light source for extreme ultraviolet lithography.


Organotin compounds

The organotin compounds are most heavily used. Worldwide industrial production probably exceeds 50,000 tonnes.


PVC stabilizers

The major commercial application of organotin compounds is in the stabilization of PVC plastics. In the absence of such stabilizers, PVC would rapidly degrade under heat, light, and atmospheric oxygen, resulting in discolored, brittle products. Tin scavenges labile chloride ions (Cl), which would otherwise strip HCl from the plastic material. Typical tin compounds are carboxylic acid derivatives of dibutyltin dichloride, such as the dilaurate.


Biocides

Some organotin compounds are relatively toxic, with both advantages and problems. They are used for biocide, biocidal properties as fungicides, pesticides, algaecides, wood preservatives, and antifouling agents. Tributyltin oxide is used as a wood preservative. Tributyltin is also used for various industrial purposes such as slime control in paper mills and disinfection of circulating industrial cooling waters. Tributyltin was used as additive for ship paint to prevent growth of Marine organisms, fouling organisms on ships, with use declining after organotin compounds were recognized as persistent organic pollutants with high toxicity for some marine organisms (the dog whelk, for example). The EU banned the use of organotin compounds in 2003, while concerns over the toxicity of these compounds to marine life and damage to the reproduction and growth of some marine species (some reports describe biological effects to marine life at a concentration of 1 nanogram per liter) have led to a worldwide ban by the International Maritime Organization. Many nations now restrict the use of organotin compounds to vessels greater than long. The persistence of tributyltin in the aquatic environment is dependent upon the nature of the ecosystem. Because of this persistence and its use as an additive in ship paint, high concentrations of tributyltin have been found in marine sediments located near naval docks. Tributyltin has been used as a biomarker for imposex in Neogastropoda, neograstropods, with at least 82 known species. With the high levels of TBT in the local inshore areas, due to shipping activities, the shellfish had an adverse effect. Imposex is the imposition of male sexual characteristics on female specimens where they grow a penis and a pallial vas deferens. A high level of TBT can damage mammalian endocrine glands, Reproductive system, reproductive and central nervous systems, bone structure and gastrointestinal tract. Not only does tributyltin affect mammals, it affects sea otters, whales, dolphins, and humans.


Organic chemistry

Some tin reagents are useful in organic chemistry. In the largest application, stannous chloride is a common reducing agent for the conversion of nitro compound, nitro and oxime groups to amines. The Stille reaction couples organotin compounds with organic halides or pseudohalogen, pseudohalides.


Li-ion batteries

Tin forms several inter-metallic phases with lithium metal, making it a potentially attractive material for battery applications. Large volumetric expansion of tin upon alloying with lithium and instability of the tin-organic electrolyte interface at low electrochemical potentials are the greatest challenges to employment in commercial cells. Tin inter-metallic compound with cobalt and carbon was implemented by Sony in its Nexelion cells released in the late 2000s. The composition of the active material is approximately Sn0.3Co0.4C0.3. Research showed that only some crystalline facets of tetragonal (beta) Sn are responsible for undesirable electrochemical activity.


Precautions

Cases of poisoning from tin metal, its oxides, and its salts are almost unknown. On the other hand, certain organotin compounds are almost as toxic as cyanide.Graf, G. G. (2000) "Tin, Tin Alloys, and Tin Compounds" in Ullmann's Encyclopedia of Industrial Chemistry, 2005 Wiley-VCH, Weinheim Exposure to tin in the workplace can occur by inhalation, skin contact, and eye contact. The US Occupational Safety and Health Administration (OSHA) set the permissible exposure limit for tin exposure in the workplace as 2 mg/m3 over an 8-hour workday. The National Institute for Occupational Safety and Health (NIOSH) determined a recommended exposure limit (REL) of 2 mg/m3 over an 8-hour workday. At levels of 100 mg/m3, tin is IDLH, immediately dangerous to life and health.


See also

* Cassiterides (the mythical Tin Islands) * List of countries by tin production * Stannary * Terne * Tin pest * Tin mining in Britain * Tinning * Whisker (metallurgy) (tin whiskers)


Notes


References


Bibliography

* * * * * * *


External links


Tin
at ''The Periodic Table of Videos'' (University of Nottingham)
Theodore Gray's Wooden Periodic Table Table
Tin samples and castings




Tin (USD cents per kg)
{{Authority control Tin, Chemical elements Post-transition metals Native element minerals Chemical elements with body-centered tetragonal structure