Thallium
30309
226115495
2008-07-16T21:54:33Z
Arkuat
29003
Characteristics: section title according to wikiproject elements
{{Elementbox_header | number=81 | symbol=Tl | name=thallium | left=[[mercury (element)|mercury]] | right=[[lead]] | above=[[indium|In]] | below=[[ununtrium|Uut]] | color1=#cccccc | color2=black }}
{{Elementbox_series | [[poor metal]]s }}
{{Elementbox_groupperiodblock | group=13 | period=6 | block=p }}
{{Elementbox_appearance_img | Tl,81| silvery white }}
{{Elementbox_atomicmass_gpm | [[1 E-25 kg|204.3833]][[List of elements by atomic mass|(2)]] }}
{{Elementbox_econfig | [[[xenon|Xe]]] 4f<sup>14</sup> 5d<sup>10</sup> 6s<sup>2</sup> 6p<sup>1</sup> }}
{{Elementbox_epershell | 2, 8, 18, 32, 18, 3 }}
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{{Elementbox_phase | [[solid]] }}
{{Elementbox_density_gpcm3nrt | 11.85 }}
{{Elementbox_densityliq_gpcm3mp | 11.22 }}
{{Elementbox_meltingpoint | k=577 | c=304 | f=579 }}
{{Elementbox_boilingpoint | k=1746 | c=1473 | f=2683 }}
{{Elementbox_heatfusion_kjpmol | 4.14 }}
{{Elementbox_heatvaporiz_kjpmol | 165 }}
{{Elementbox_heatcapacity_jpmolkat25 | 26.32 }}
{{Elementbox_vaporpressure_katpa | 882 | 977 | 1097 | 1252 | 1461 | 1758 | comment= }}
{{Elementbox_section_atomicprop | color1=#cccccc | color2=black }}
{{Elementbox_crystalstruct | hexagonal }}
{{Elementbox_oxistates | 3, '''1'''<br />(mildly [[base (chemistry)|basic]] oxide) }}
{{Elementbox_electroneg_pauling | 1.62 }}
{{Elementbox_ionizationenergies3 | 589.4 | 1971 | 2878 }}
{{Elementbox_atomicradius_pm | [[1 E-10 m|190]] }}
{{Elementbox_atomicradiuscalc_pm | [[1 E-10 m|156]] }}
{{Elementbox_covalentradius_pm | [[1 E-10 m|148]] }}
{{Elementbox_vanderwaalsrad_pm | [[1 E-10 m|196]] }}
{{Elementbox_section_miscellaneous | color1=#cccccc | color2=black }}
{{Elementbox_magnetic | ??? }}
{{Elementbox_eresist_ohmmat20 | 0.18 µ}}
{{Elementbox_thermalcond_wpmkat300k | 46.1 }}
{{Elementbox_thermalexpansion_umpmkat25 | 29.9 }}
{{Elementbox_speedofsound_rodmpsat20 | 818 }}
{{Elementbox_youngsmodulus_gpa | 8 }}
{{Elementbox_shearmodulus_gpa | 2.8 }}
{{Elementbox_bulkmodulus_gpa | 43 }}
{{Elementbox_poissonratio | 0.45 }}
{{Elementbox_mohshardness | 1.2 }}
{{Elementbox_brinellhardness_mpa | 26.4 }}
{{Elementbox_cas_number | 7440-28-0 }}
{{Elementbox_isotopes_begin | color1=#cccccc | color2=black }}
{{Elementbox_isotopes_stable | mn=203 | sym=Tl | na=29.524% | n=122 }}
{{Elementbox_isotopes_decay2 | mn=204 | sym=Tl
| na=[[synthetic radioisotope|syn]] | hl=119 Ms<br />(3.78 [[year|y]])
| dm1=[[beta emission|β<sup>-</sup>]] | de1=0.764 | pn1=204 | ps1=[[lead|Pb]]
| dm2=[[electron capture|ε]] | de2=0.347 | pn2=204 | ps2=[[mercury (element)|Hg]] }}
{{Elementbox_isotopes_stable | mn=205 | sym=Tl | na=70.476% | n=124 }}
{{Elementbox_isotopes_end}}
{{Elementbox_footer | color1=#cccccc | color2=black }}
'''Thallium''' ({{pronEng|ˈθæliəm}}) is a [[chemical element]] with the symbol '''Tl''' and [[atomic number]] 81.<ref>[http://periodic.lanl.gov/elements/81.html ''thallium''], Los Alamos National Laboratory. Retrieved [[November 21]], [[2006]].</ref> This soft gray malleable [[poor metal]] resembles [[tin]] but discolors when exposed to air. Approximately 60-70% of thallium production is used in the [[electronics industry]], and the rest is used in the [[pharmaceutical industry]] and in [[glass|glass manufacturing]].<ref name="sl2001"/> It is also used in [[infrared detector]]s.<Ref>
{{cite web
| url = http://adsabs.harvard.edu/abs/1977ApOpt..16.2942N
| title = Thallium selenide infrared detector
| accessdate = 2006-11-25
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| author = Nayer, P. S
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| coauthors = Hamilton, O.
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| publisher = Smithsonian/NASA ADS Physics Abstract Service
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Thallium is highly [[toxic]] and is used in [[rat poison]]s and [[insecticide]]s, and its use has been cut back or eliminated in many countries. It is used in [[murders]] and has the nicknames "The Poisoner's Poison" and "Inheritance powder" (alongside [[arsenic]]).
== Characteristics ==
[[Image:Thallium.jpg|thumb|left|1 gram of Thallium]]
<p>Thallium is very soft and malleable and can be cut with a knife. It has a metallic [[luster]], but when exposed to air, it quickly tarnishes with a bluish-gray tinge that resembles [[lead]]. (It is preserved by keeping it under oil). A heavy layer of [[oxide]] builds up on thallium if left in air. In the presence of water, thallium [[hydroxide]] is formed.
== Occurrence and production ==
Thallium occurs naturally in the minerals [[crookesite]], [[lorandite]], [[hutchinsonite]], and [[pyrite]].<ref name="sl2001">{{cite web|title=Chemical fact sheet — Thallium | publisher=''Spectrum Laboratories'' | year=2001 | month=April | url=http://www.speclab.com/elements/thallium.htm | accessdate=2008-02-02}}</ref>
Thallium metal is obtained as a by-product in the production of sulfuric acid by roasting of pyrite, and also in the smelting of lead and zinc ores.<ref name="sl2001"/>
== Applications ==
The [[odor]]less and [[taste]]less [[Thallium(I) sulfate|thallium sulfate]] was once widely used as [[rat poison]] and [[ant]] killer. Since 1975, this use in the [[United States]] and many other countries is prohibited due to safety concerns.<ref name="sl2001"/> Other uses:
*[[thallium sulfide]]'s [[electrical conductivity]] changes with exposure to [[infrared light]] therefore making this compound useful in [[photocell]]s.
*Thallium(III) salts, as thallium trinitrate or triacetate, are useful reagents in organic synthesis performing different transformations in aromatics, ketones, olefins, among others.
*thallium [[bromide]]-[[iodide]] [[crystal]]s have been used as infrared optical materials, because they are harder than other common infrared optics, and because they have transmission at significantly longer wavelengths. The trade name KRS-5 refers to this material.
*[[thallium oxide]] has been used to manufacture [[glass]]es that have a high [[refractive index|index of refraction]].
*used in [[semiconductor]] materials for selenium rectifiers,
*used as a [[dopant]] for [[sodium iodide]] crystals in [[gamma radiation]] detection equipment, such as [[scintillation counter]]s,
*high-density liquid used for sink-float separation of [[mineral]]s,
*used in the treatment of [[ringworm]] and other [[skin infection]]s. However this use has been limited due to the narrow [[therapeutic index]].
*[[radioactive]] thallium-201 (half-life of 73 hours) is used for diagnostic purposes in [[nuclear medicine]], particularly in stress tests used for risk stratification in patients with [[coronary artery disease]] A(CAD).<ref>[http://www.wramc.amedd.army.mil/departments/nuclear/PatientInfo/Thallium.htm Thallium Test] from [[Walter Reed Army Medical Center]]</ref><ref>[http://www.americanheart.org/presenter.jhtml?identifier=4743 Thallium Stress Test] from the [[American Heart Association]]</ref> This isotope of thallium can be generated using a transportable generator which is similar to the [[Technetium-99m generator|technetium cow]].<ref>[http://www.medscape.com/medline/abstract/7169272 Abstract]<!-- dead link --></ref> The generator contains [[lead]]-201 (half life 9.33 hours) which decays by [[electron capture]] to the thallium-201. The lead-201 can be produced in a [[cyclotron]] by the bombardment of thallium with [[proton]]s or [[deuteron]]s by the (p,3n) and (d,4n) reactions.<ref>[http://www.med.harvard.edu/JPNM/physics/isotopes/Tl/Tl201/prod.html Thallium-201 production] from [[Harvard Medical School]]'s Joint Program in Nuclear Medicine</ref>
*combined with [[sulfur]] or [[selenium]] and [[arsenic]], thallium has been used in the production of high-[[density]] glasses that have low [[melting point]]s in the range of 125 and 150 [[Celsius|°C]]. These glasses have room temperature properties that are similar to ordinary glasses and are durable, insoluble in water and have unique [[refractive indices]].
*an 8.5% thallium amalgam is used in thermometers and switches for use in low temperatures, because it freezes at -58 °C (pure mercury freezes at -38 °C).<ref name="sl2001"/>
*thallium is used in the electrodes in [[oxygen analyzer|dissolved oxygen analyzers]].<ref name="sl2001"/>
*thallium is a constituent of the alloy in the anode plates in magnesium seawater batteries.<ref name="sl2001"/>
In addition, research activity with thallium is ongoing to develop high-temperature [[Superconductivity|superconducting]] materials for such applications as [[magnetic resonance imaging]], storage of magnetic energy, [[magnetic propulsion]], and [[electric power generation]] and transmission.
== History ==
Thallium ([[Greek language|Greek]] ''θαλλός'', ''thallos'', meaning "a green shoot or twig")<ref>Liddell & Scott, ''[http://perseus.mpiwg-berlin.mpg.de/cgi-bin/resolveform?doc=Perseus%3Atext%3A1999.04.0057;layout=;query=toc;loc=qallo%2Fs A Greek-English Lexicon]'', ''sub'' ''[http://perseus.mpiwg-berlin.mpg.de/cgi-bin/resolveform?lookup=qallos&type=begin&lang=greek&searchText=&options=Sort+Results+Alphabetically&.submit=Submit&formentry=1&lang=greek θαλλος]''</ref> was discovered by [[Sir William Crookes]] in [[1861]] in [[England]] while he was making spectroscopic determinations for [[tellurium]] on residues from a [[sulfuric acid]] plant. The name comes from Thallium's bright [[green]] spectral [[emission line]]s. In 1862 Crookes and [[Claude-Auguste Lamy]] isolated the metal independently of each other.
== Occurrence ==
Although the metal is reasonably abundant in the [[Earth]]'s crust at a concentration estimated to be about 0.7 mg/kg, mostly in association with [[potassium]] minerals in [[clay]]s, [[soil]]s, and [[granite]]s, it is not generally considered to be commercially recoverable from those forms. The major source of commercial thallium is the trace amounts found in [[copper]], [[lead]], [[zinc]], and other [[sulfide]] [[ore]]s.
Thallium is found in the minerals [[crookesite]] TlCu<sub>7</sub>Se<sub>4</sub>, [[hutchinsonite]] TlPbAs<sub>5</sub>S<sub>9</sub>, and [[lorandite]] TlAsS<sub>2</sub>. It also occurs as trace in [[pyrite]] and extracted as a by-product of roasting this ore for sulfuric acid production. The metal can be obtained from the [[smelting]] of lead and zinc rich ores. [[Manganese nodule]]s found on the [[ocean floor]] also contain thallium, but nodule extraction is prohibitively expensive and potentially environmentally destructive. In addition, several other thallium minerals, containing 16% to 60% thallium, occur in nature as sulfide or selenide complexes with [[antimony]], [[arsenic]], copper, lead, and [[silver]], but are rare, and have no commercial importance as sources of this element. See also: ''[[:Category:Thallium minerals]].''
== Isotopes ==
{{main|isotopes of thallium}}
Thallium has 25 [[isotope]]s which have [[atomic mass]]es that range from 184 to 210. <sup>203</sup>Tl and <sup>205</sup>Tl are the only stable isotopes, and <sup>204</sup>Tl is the most stable [[radioisotope]], with a [[half-life]] of 3.78 years.
<sup>202</sup>Th (half life 12.23 days) can be made in a cyclotron,<ref>[http://www.eh.doe.gov/ohre/roadmap/histories/0472/0472d.html Thallium Research] from [[United States Department of Energy|Department of Energy]]</ref> while <sup>204</sup>Th (half life 3.78 years) is made by the [[neutron activation]] of stable thallium in a [[nuclear reactor]].<ref>[http://www-pub.iaea.org/MTCD/publications/PDF/te_1340_web.pdf Manual for reactor produced radioisotopes] from the [[International Atomic Energy Agency]]</ref>
== Compounds ==
Fluorides: TlF, TlF<sub>3</sub><br />
Chlorides: TlCl, TlCl<sub>2</sub>, TlCl<sub>3</sub><br />
Bromides: TlBr, Tl<sub>2</sub>Br<sub>4</sub><br />
Iodides: TlI, TlI<sub>3</sub><br />
Hydrides: none listed<br />
Oxides: Tl<sub>2</sub>O, Tl<sub>2</sub>O<sub>3</sub><br />
Sulfides: Tl<sub>2</sub>S<br />
Selenides: Tl<sub>2</sub>Se<br />
Tellurides:
none listed<br />
Nitrides:
none listed
== Toxicity ==
[[Image:Skull and crossbones.svg|left|80px]]
Thallium and its compounds are very toxic, and should be handled with great care[http://www.webelements.com/webelements/elements/text/Tl/biol.html]. Contact with skin is dangerous, and adequate ventilation should be provided when melting this metal[http://www.webelements.com/webelements/elements/text/Tl/biol.htm].Thallium(I) compounds have a high aqueous [[solubility]] and are readily absorbed through the skin. Exposure to them should not exceed 0.1 [[milligram|mg]] per [[square metre|m²]] of skin in an 8-hour time-weighted average (40-hour work week). Thallium is a suspected human [[carcinogen]].
Part of the reason for thallium's high toxicity is that, when present in aqueous solution as the univalent thallium(I) ion (Tl<sup>+</sup>), it exhibits some similarities with essential [[alkali metal]] cations, particularly [[potassium]] (as the atomic radius is almost identical). It can thus enter the body via potassium uptake pathways. However, other aspects of thallium's chemistry are very different from that of the alkali metals (''e.g.'', its high affinity for [[sulfur]] ligands due to the presence of empty d-orbitals), and so this substitution disrupts many cellular processes (for instance, thallium may attack sulfur-containing proteins such as [[cysteine]] residues and [[ferredoxin]]s).
Thallium's toxicity has led to its use (now discontinued in many countries) as a [[rat]] and [[ant]] poison.
Among the distinctive effects of thallium poisoning are [[alopecia|loss of hair]] (which led it to its initial use as a [[depilatory]] before its toxicity was properly appreciated) and damage to peripheral nerves (victims may experience a sensation of walking on hot coals). Thallium was once an effective murder weapon before its effects became understood, and an antidote ([[prussian blue]]) discovered.
== Treatment and internal decontamination ==
One of the main methods of removing thallium (both radioactive and normal) from humans is to use [[Prussian blue]], which is a solid [[ion exchange]] material which absorbs thallium and releases [[potassium]]. The prussian blue is fed by mouth to the person, and it passes through their digestive system and comes out in the [[Human feces|stool]].<ref>[http://www.bt.cdc.gov/radiation/prussianblue.asp Prussian blue fact sheet] from the [[Centers for Disease Control and Prevention]]</ref>
== Famous uses as a poison ==
* In 1953, [[Australia]]n [[Caroline Grills]] was sentenced to life in prison after three family members and a close family friend died. Authorities found thallium in tea that she had given to two additional family members.<ref name="bbc-thallium">[http://news.bbc.co.uk/1/hi/uk/6163520.stm ''What is thallium?''], BBC, [[November 19]], [[2006]]. Retrieved [[November 21]], [[2006]].</ref>
* In 1957, [[Nikolai Khokhlov]], a former [[KGB]] assassin, was poisoned with thallium.<ref name="mitro">{{cite book | author=[[Christopher Andrew]] and [[Vasili Mitrokhin]] | title=The [[Mitrokhin Archive]]: The KGB in Europe and the West | publisher=Gardners Books | year=2000 | isbn=0-14-028487-7}}</ref> Khokhlov fell ill with stomach cramps and nausea and within days his hair had fallen out and he was covered with marks on his skin. He fled the Soviet Union to Germany where doctors suspected thallium poisoning and tried every known antidote without success. Khokhlov was then taken to the US hospital and treated with [[hydrocortisone]], steroids, and blood and plasma transfusions and he eventually recovered.
* In 1971, thallium was the main poison that [[Graham Frederick Young]] used to poison around 70 people in the English village of [[Bovingdon]], [[Hertfordshire]], of which 2 died.{{Fact|date=February 2008}}
*[[Zhu Ling (1973)]] the victim of an unsolved 1995 thallium poisoning case in Beijing, China. In 1994, Zhu Ling was a sophomore in Class Wuhua2 (Physical Chemistry) at Tsinghua University in Beijing. She began to show strange and debilitating symptoms at the end of 1994, when she reported experiencing acute stomach pain, along with extensive hair loss. Ultimately she was diagnosed on [[Usenet]] with poisoning by thallium. To this date speculation of the true poisoner is still discussed by many Chinese expatriates overseas
* In 1988, members of the Carr family from Alturas, Polk County, Florida fell ill from what appeared to be thallium poisoning. Peggy Carr, the mother, died slowly and painfully from the poison. Her son and stepson were critically ill but eventually recovered. The Carr's neighbor, [[George J. Trepal]], a chemist and member of [[Mensa_International|Mensa]], was convicted of murdering Mrs. Carr and attempting to murder her family and sentenced to death. The thallium was slipped into bottles of Coca-Cola at the Carr's home and Trepal's.<ref>{{cite web|url=http://www.floridacapitalcases.state.fl.us/case_updates/121965.doc|title=The Case of TREPAL, George (W/M)|publisher=The Commission on Capital Cases|accessdate=2007-11-29}}</ref>
[[Image:Thallium rod corroded.jpg|thumb|right|Corroded thallium rod]]
* In June 2004, 25 Russian soldiers earned Honorable Mention [[Darwin Awards]] after becoming ill from thallium exposure when they found a can of mysterious white powder in a rubbish dump on their base at [[Khabarovsk]] in the Russian Far East. Oblivious to the danger of misusing an unidentified white powder from a military dump site, the conscripts added it to tobacco, and used it as a substitute for [[talcum powder]] on their feet.<ref>[http://darwinawards.com/stupid/stupid2004-16.html White Russians] at DarwinAwards.com</ref>
* In 2005, a 17 year old girl in [[Numazu, Shizuoka|Numazu]], [[Shizuoka Prefecture|Shizuoka]], [[Japan]], admitted to attempting to murder her mother by lacing her tea with thallium, causing a national scandal.<ref>[http://www.gaijinpot.com/read_news.php?id=6623 ''Girl admits trying to kill mom by lacing her tea''], "GaijinPot", [[April 28]], [[2005]]. News Source from [[Mainichi Shimbun]]. Retrieved [[November 21]], [[2006]].</ref>
* In February 2007, two Americans, Marina and Yana Kovalevsky, a mother and daughter, visiting Russia were hospitalized due to thallium poisoning. Both had emigrated from the Soviet Union to the United States in 1989 and had made several trips to Russia since then.<ref>[http://www.foxnews.com/story/0,2933,257278,00.html ''Embassy Confirms Hospitalization of Two Americans for Thallium Poisoning''], Foxnews.com, [[March 7]], [[2007]]. Retrieved [[March 7]], [[2007]].</ref>
* In February 2008, members of Iraqi air force club and some of their children were poisoned by cake laced with thallium.<ref>[http://news.bbc.co.uk/2/hi/middle_east/7237086.stm ''Poison cake kills Iraqi children''], news.bbc.co.uk, [[February 9]], [[2008]]. Retrieved [[February 9]], [[2008]].</ref> Two of the children died.
=== In fiction ===
* [[Agatha Christie]], who worked as a [[pharmacist]], used thallium as the agent of murder in her [[detective fiction]] novel [[The Pale Horse (novel)|''The Pale Horse'']] — the first clue to the murder method coming from the hair loss of the victims.
* In [[Nigel Williams (author)|Nigel Williams]]' 1990 novel ''[[The Wimbledon Poisoner]]'', Henry Far uses thallium to [[baste]] a roast chicken in a failed attempt to murder his wife.
* Thallium figures prominently in the 1995 film ''[[The Young Poisoner's Handbook]]'', a dark comedy loosely based on the life of [[Graham Frederick Young]].
* "Concentrated thallium" is used as the poison of choice of the Wyoming Widow in the 2006 comedy ''[[Big Nothing]]''
==See also==
* [[:Category:Thallium compounds|Thallium compounds]]
== References ==
{{reflist}}
== External links ==
{{Commons|Thallium}}
{{wiktionary|thallium}}
*[http://www.webelements.com/webelements/elements/text/Tl/index.html WebElements.com — Thallium]
*[http://www.emedicine.com/emerg/topic926.htm Toxicity, Thallium]
*[http://www.timesonline.co.uk/article/0,,251-2461655,00.html Slow-acting killer that was Saddam's favourite instrument of vengeance]
*[http://toxnet.nlm.nih.gov/cgi-bin/sis/search/r?dbs+hsdb:@term+@na+@rel+thallium,+elemental NLM Hazardous Substances Databank – Thallium, Elemental]
*[http://www.floridacapitalcases.state.fl.us/case_updates/121965.doc]
*[http://www.crimelibrary.com/criminal_mind/forensics/cyril_wecht/7.html Cyril Wecht, Thallium, Robert Curley]
*[http://www.atsdr.cdc.gov/tfacts54.html ATSDR - ToxFAQs]
*[http://www.guardian.co.uk/Iraq/Story/0,,2254956,00.html The Guardian reports: Two Iraqi children die from Thallium poisoning: 9 February 2008]
*[http://www.pse-mendelejew.de/bilder/tl.jpg pure Thallium >=99,99% picture in the element collection from Heinrich Pniok]
*[http://www.smart-elements.com/?arg=zoom&element=Tl&art=1967&newitems=&ref=Tl&seite=0&total=1&suche=#magnify pure Thallium casted in acrylic for safe handling]
{{clear}}
{{Compact periodic table}}
[[Category:Chemical elements]]
[[Category:Element toxicology]]
[[Category:Poor metals]]
[[Category:Thallium]]
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