Indium 14749 226158239 2008-07-17T02:17:32Z Arkuat 29003 /* Characteristics */ section title per discussion at [[WP:WikiProject Elements]] {{Elementbox_header | number=49 | symbol=In | name=indium | left=[[cadmium]] | right=[[tin]] | above=[[gallium|Ga]] | below=[[thallium|Tl]] | color1=#cccccc | color2=black }} {{Elementbox_series | [[poor metal]]s }} {{Elementbox_groupperiodblock | group=13 | period=5 | block=p }} {{Elementbox_appearance_img | In,49| silvery lustrous gray }} {{Elementbox_atomicmass_gpm | 114.818[[List of elements by atomic mass|(3)]] }} {{Elementbox_econfig | &#91;[[krypton|Kr]]&#93; 4d<sup>10</sup> 5s<sup>2</sup> 5p<sup>1</sup> }} {{Elementbox_epershell | 2, 8, 18, 18, 3 }} {{Elementbox_section_physicalprop | color1=#cccccc | color2=black }} {{Elementbox_phase | [[solid]] }} {{Elementbox_density_gpcm3nrt | 7.31 }} {{Elementbox_densityliq_gpcm3mp | 7.02 }} {{Elementbox_meltingpoint | k=429.75 | c=156.60 | f=313.88 }} {{Elementbox_boilingpoint | k=2345 | c=2072 | f=3762 }} {{Elementbox_heatfusion_kjpmol | 3.281 }} {{Elementbox_heatvaporiz_kjpmol | 231.8 }} {{Elementbox_heatcapacity_jpmolkat25 | 26.74 }} {{Elementbox_vaporpressure_katpa | 1196 | 1325 | 1485 | 1690 | 1962 | 2340 | comment= }} {{Elementbox_section_atomicprop | color1=#cccccc | color2=black }} {{Elementbox_crystalstruct | tetragonal }} {{Elementbox_oxistates | 3<br />([[amphoteric]] oxide) }} {{Elementbox_electroneg_pauling | 1.78 }} {{Elementbox_ionizationenergies4 | 558.3 | 1820.7 | 2704 }} {{Elementbox_atomicradius_pm | 155 }} {{Elementbox_atomicradiuscalc_pm | 156 }} {{Elementbox_covalentradius_pm | 144 }} {{Elementbox_vanderwaalsrad_pm | 193 }} {{Elementbox_section_miscellaneous | color1=#cccccc | color2=black }} {{Elementbox_magnetic | no data }} {{Elementbox_eresist_ohmmat20 | 83.7 n}} {{Elementbox_thermalcond_wpmkat300k | 81.8 }} {{Elementbox_thermalexpansion_umpmkat25 | 32.1 }} {{Elementbox_speedofsound_rodmpsat20 | 1215 }} {{Elementbox_youngsmodulus_gpa | 11 }} {{Elementbox_mohshardness | 1.2 }} {{Elementbox_brinellhardness_mpa | 8.83 }} {{Elementbox_cas_number | 7440-74-6 }} {{Elementbox_isotopes_begin | color1=#cccccc | color2=black }} {{Elementbox_isotopes_stable | mn=113 | sym=In | na=4.3% | n=64 }} {{Elementbox_isotopes_decay | mn=115 | sym=In | na=95.7% | hl=4.41&times;10<sup>14</sup>[[year|y]] | dm=[[beta emission|Beta<sup>-</sup>]] | de=0.495 | pn=115 | ps=[[tin|Sn]] }} {{Elementbox_isotopes_end}} {{Elementbox_footer | color1=#cccccc | color2=black }} '''Indium''' ({{pronEng|ˈɪndiəm}}) is a [[chemical element]] with chemical symbol '''In''' and [[atomic number]] 49. This rare, soft, malleable and easily fusible [[poor metal]] is chemically similar to [[aluminium]] or [[gallium]] but more closely resembles [[zinc]] (zinc ores are also the primary source of this metal). Its current primary application is to form transparent electrodes from [[indium tin oxide]] in [[liquid crystal display]]s. It is widely used in thin-films to form lubricated layers (during [[World War II]] it was widely used to coat bearings in high-performance [[aircraft]]). It's also used for making particularly low melting point alloys, and is a component in some lead-free solders. == Characteristics == Indium is a very soft, silvery-[[white]], relatively rare true [[metal]] with a bright [[Lustre (mineralogy)|luster]]. As a pure metal indium emits a high-pitched "[[tin cry|cry]]", when it is bent. Both [[gallium]] and indium are able to [[wetting|wet]] [[glass]]. One unusual property of indium is that its most common [[isotope]] is slightly radioactive; it very slowly decays by [[beta emission]] to [[tin]]. This radioactivity is not considered hazardous, mainly because its half-life is 4.41{{e|14}} years, four orders of magnitude larger than the age of the universe and nearly 50,000 times longer than that of natural [[thorium]]. Unlike its [[Period 5 element|period 5]] neighbor [[cadmium]], indium is not a notorious [[cumulative poison]]. == Applications == The first large-scale application for indium was as a coating for [[bearing (mechanical)|bearing]]s in high-performance [[aircraft]] engines during [[World War II]]. Afterwards, production gradually increased as new uses were found in fusible [[alloy]]s, [[solder]]s, and [[electronics]]. In the [[1950s]], tiny beads of it were used for the emitters and collectors of PNP [[alloy junction transistor]]s. In the middle and late [[1980s]], the development of indium phosphide [[semiconductor]]s and [[indium tin oxide]] thin films for [[liquid crystal display]]s (LCD) aroused much interest. By 1992, the thin-film application had become the largest end use. Other uses: *For manufacture of low-melting-temperature [[alloy]]s. An alloy consisting of 24% indium and 76% [[gallium]] is [[liquid]] at room temperature. *Some indium compounds such as [[indium antimonide]], [[indium phosphide]], and [[indium nitride]] are [[semiconductor]]s with useful properties. *Component required for synthesis of the semiconductor [[Copper indium gallium selenide]] (CIGS), which is used for the manufacture of [[thin film]] [[solar cells]]. *Used in [[light-emitting diode]]s (LEDs) and Laser Diodes (LDs) based on [[compound semiconductor]]s such as [[InGaN]], [[InGaP]] that are fabricated by Metalorganic Vapor Phase Epitaxy ([[MOVPE]]) technology. *The ultrapure [[metalorganics]] of indium, specifically high purity [[trimethylindium]] (TMI) is used as a precursor in III-V [[compound semiconductor]]s, while it is also used as the [[semiconductor]] [[dopant]] in II-VI [[compound semiconductor]]s. <ref>Journal of Crystal Growth {{doi|10.1016/j.jcrysgro.2004.09.006}}</ref> *Can also be plated onto metals and evaporated onto glass which forms a [[mirror]] which is as good as those made with [[silver]] but has higher [[corrosion]] resistance. *[[indium(III) oxide|Indium oxide]] (In<sub>2</sub>O<sub>3</sub>) is used as a [[transparency (optics)|transparent]] [[electrical conductor|conductive]] [[glass]] substrate in the making of [[electroluminescent]] panels. *Used as a light filter in [[sodium vapor lamp#Low pressure / LPS / SOX|low pressure sodium vapor lamp]]s. *Indium's freezing point of 429.7485 K (156.5985 °C) is a defining fixed point on the international temperature scale [[ITS-90]]. *Indium's high neutron capture cross section for thermal neutrons makes it suitable for use in [[control rod]]s for nuclear reactors, typically in an alloy containing 80% silver, 15% indium, and 5% cadmium. *In nuclear engineering, the (n,n') reactions of <sup>113</sup>In and <sup>115</sup>In are used to determine magnitudes of neutron fluxes. *<sup>111</sup>In emits gamma radiation and is used in scintigraphy, a technique of [[medical imaging]]. Scintigraphy has many applications, including early phase drug development, and monitoring the activity of [[white blood cell]]s. A [[blood test]] is taken from the patient, white cells removed and labelled with the [[Radioactive decay|radioactive]] <sup>111</sup>In, then re-injected back into the patient. Gamma imaging will reveal any areas of high white cell activity such as an [[abscess]]. *Very small amounts used in aluminium alloy sacrificial anodes (for salt water applications) to prevent [[passivation]] of the aluminium. *In the form of a wire it is used as a vacuum seal in cryogenics applications. *Used as a calibration material for thermogravimetric analysis devices. == History == Indium (named after the [[indigo]] line in its [[atomic spectrum]]) was discovered by the German [[Ferdinand Reich]] and [[Hieronymous Theodor Richter]] in [[1863]] while they were testing [[zinc]] ores with a [[spectrograph]] in search of [[thallium]]. Richter went on to isolate the metal in [[1867]]. == Occurrence and consumption == [[Image:Indium wire.jpg|thumb|left|Ductile Indium wire]] Indium ranks 61st in abundance in the Earth's crust at approximately 0.25 ppm <ref>{{cite web | title= The Element Indium | work = It's Elemental | url = http://education.jlab.org/itselemental/ele049.html | accessdate = 2007-12-26}}</ref>, which means it is more than three times as abundant as silver, which occurs at 0.075 ppm <ref>{{cite web | title= The Element Silver| work = It's Elemental | url = http://education.jlab.org/itselemental/ele047.html | accessdate = 2007-12-26}}</ref>. Up until [[1924]], there was only about a [[gram]] of isolated indium on the planet. Indium is produced mainly from residues generated during [[zinc]] [[ore]] processing but is also found in [[iron]], [[lead]], and [[copper]] ores. Canada is a leading producer of indium. The [[Teck Cominco]] refinery in [[Trail, BC]], is the largest single source, with production of 32,500 kg in 2005, 41,800 kg in 2004 and 36,100 kg in 2003. The amount of indium consumed is largely a function of worldwide [[LCD]] production. Worldwide production is currently 476 tonnes per year from mining and a further 650 tonnes per year from recycling <ref>{{cite web | title = Indium and Gallium Supply Sustainability September 2007 Update | work = 22nd EU PV Conference, Milan, Italy | format = pdf | url = http://www.indium.com/_dynamo/download.php?docid=552 | accessdate = 2007-12-26}}</ref>. Demand has risen rapidly in recent years with the popularity of LCD computer monitors and televisions, which now account for 50% of indium consumption <ref>{{cite web | title = Indium Price Supported by LCD Demand and New Uses for the Metal | work = Geology.com | format = pdf | url = http://geology.com/articles/indium.shtml | accessdate = 2007-12-26}}</ref>. Increased manufacturing efficiency and recycling (especially in [[Japan]]) maintain a balance between demand and supply. Demand increased as the metal is used in LCDs and televisions, and supply decreased when a number of [[China|Chinese]] [[mining]] concerns stopped extracting indium from their [[zinc]] tailings. In 2002, the price was [[United States dollar|US$]]94 per kilogram. The recent changes in demand and supply have resulted in high and fluctuating prices of indium, which from 2005 to 2007 ranged from US$700/kg to US$1,000/kg <ref>{{cite web | title = Indium (Mineral Commodities Summary 2007)| work = USGS Minerals Information | format = pdf | url = http://minerals.usgs.gov/minerals/pubs/commodity/indium/indiumcs07.pdf | accessdate = 2007-12-26}}</ref>. Demand for indium is likely to continue to increase with large-scale manufacture of [[Copper indium gallium selenide|CIGS]]-based thin film solar technology starting by several companies in 2008, including [[Nanosolar]] and [[Miasole]]. Based on content of indium in zinc ore stocks, there is a world-wide reserve base of approximately 6,000 tonnes of economically-viable indium <ref>{{cite web | title = Indium (Mineral Commodities Summary 2007)| work = USGS Minerals Information | format = pdf | url = http://minerals.usgs.gov/minerals/pubs/commodity/indium/indiumcs07.pdf | accessdate = 2007-12-26}}</ref>. This figure has led to estimates suggesting that, at current consumption rates, there is only 13 years' supply of indium left <ref>{{cite journal | date=[[May 26]], [[2007]] | journal = New Scientist | volume = 194 | issue = 2605 | pages = 38–39 | issn = 0262-4079 | title = How Long Will it Last? | url = http://environment.newscientist.com/channel/earth/mg19426051.200-earths-natural-wealth-an-audit.html}}</ref>. However, such estimates are often regarded as [[alarmist]] and [[scaremongering]] <ref>{{cite journal | date=[[June 16]], [[2007]] | journal = New Scientist | volume = 194 | issue = 2608 | pages = 26 | issn = 0262-4079 | title = Find More Ore | url = http://www.newscientist.com/article/mg19426080.200-find-more-ore.html }}</ref>. The Indium Corporation, the largest processor of indium, claims that, on the basis of increasing recovery yields during extraction, recovery from a wider range of base metals (including tin, copper and other polymetallic deposits) and new mining investments, the long-term supply of indium is sustainable, reliable and sufficient to meet increasing future demands <ref>{{cite web | title = Indium and Gallium Supply Sustainability September 2007 Update | work = 22nd EU PV Conference, Milan, Italy | format = pdf | url = http://www.indium.com/_dynamo/download.php?docid=552 | accessdate = 2007-12-26}}</ref>. This conclusion also seems reasonable in light of the fact that silver, a less abundant element, is currently mined at approximately 18,300 tonnes per annum <ref>{{cite web | title = Top World Silver Producers | url = http://www.nma.org/pdf/g_silver_producers.pdf | format = pdf | work = World Silver Survey 2007 }}</ref>, which is 40 times greater than current indium mining rates. On the other hand, replacements for indium tin oxide are already on the horizon. According to recent research, mass production of transparent conductors made from [[graphene]], a modification of the virtually inexhaustible [[element]] [[carbon]] discovered in [[2004]], may be just years away. <ref>{{cite web | date=[[June 23]], [[2008]] | title = Graphene-based gadgets may be just years away | url = http://www.physorg.com/news128776023.html}}</ref>. == Precautions == Pure indium in metal form is considered non-toxic by most sources. In the [[welding]] and [[semiconductor]] industries, where indium exposure is relatively high, there have been no reports of any toxic side-effects. This may not be the case with indium compounds: there is some unconfirmed evidence that suggests that indium has a low level of [[toxic]]ity. For example, [[indium trichloride]] anhydrous (InCl<sub>3</sub>) is quite toxic, while [[indium phosphide]] (InP) is both toxic and a suspected [[carcinogen]]. ==See also== * [[:Category:Indium compounds|Indium compounds]] ==References== <references/> *[http://periodic.lanl.gov/elements/49.html Los Alamos National Laboratory &ndash; Indium] ==External links== {{Commons|Indium}} {{wiktionary|indium}} *[http://www.webelements.com/webelements/elements/text/In/index.html WebElements.com &ndash; Indium] *[http://www.indium.com The Indium Corporation] *[http://www.organic-chemistry.org/chemicals/reductions/indiumlowvalent.shtm Reducing Agents > Indium low valent] *[http://www.pse-mendelejew.de/bilder/in.jpg Indium picture in the element collection from Heinrich Pniok] {{clear}} {{compact periodic table}} [[Category:Chemical elements]] [[Category:Poor metals]] [[Category:Indium|*]] {{Link FA|de}} <!-- interwiki --> [[af:Indium]] [[ar:إنديوم]] [[bn:ইন্ডিয়াম]] [[be:Індый]] [[bs:Indijum]] [[ca:Indi (element)]] [[cs:Indium]] [[co:Indiu]] [[da:Indium]] [[de:Indium]] [[et:Indium]] [[el:Ίνδιο]] [[es:Indio (elemento)]] [[eo:Indio]] [[eu:Indio]] [[fa:ایندیوم]] [[fr:Indium]] [[fur:Indi]] [[ga:Indiam]] [[gv:Indjum]] [[gl:Indio]] [[ko:인듐]] [[hy:Ինդիում]] [[hi:इण्डियम]] [[hr:Indij]] [[io:Indio]] [[id:Indium]] [[is:Indín]] [[it:Indio]] [[he:אינדיום]] [[jv:Indium]] [[sw:Indi]] [[ht:Endyòm]] [[ku:Îndiyûm]] [[la:Indium]] [[lv:Indijs]] [[lb:Indium]] [[lt:Indis]] [[li:Indium]] [[jbo:blajinme]] [[hu:Indium]] [[mk:Индиум]] [[ml:ഇന്റിയം]] [[mr:इंडियम]] [[nl:Indium]] [[ja:インジウム]] [[no:Indium]] [[nn:Indium]] [[oc:Indi (quimia)]] [[uz:Indiy]] [[pl:Ind]] [[pt:Índio (elemento químico)]] [[ro:Indiu]] [[qu:Indyu]] [[ru:Индий]] [[scn:Ìndiu]] [[simple:Indium]] [[sk:Indium]] [[sl:Indij]] [[sr:Индијум]] [[sh:Indijum]] [[fi:Indium]] [[sv:Indium]] [[ta:இண்டியம்]] [[th:อินเดียม]] [[vi:Indi]] [[tr:İndiyum]] [[uk:Індій]] [[zh:铟]]