View source for Tellurium

{{Elementbox_header | number=52 | symbol=Te | name=tellurium | left=[[antimony]] | right=[[iodine]] | above=[[selenium|Se]] | below=[[polonium|Po]] | color1=#cccc99 | color2=black }}
{{Elementbox_series | [[metalloid]]s }}
{{Elementbox_groupperiodblock | group=16 | period=5 | block=p }}
{{Elementbox_appearance_img | Te,52| silvery lustrous gray }}
{{Elementbox_atomicmass_gpm | [[1 E-25 kg|127.60]][[List of elements by atomic mass|(3)]] }}
{{Elementbox_econfig | &#91;[[krypton|Kr]]&#93; 5s<sup>2</sup> 4d<sup>10</sup> 5p<sup>4</sup> }}
{{Elementbox_epershell | 2, 8, 18, 18, 6 }}
{{Elementbox_section_physicalprop | color1=#cccc99 | color2=black }}
{{Elementbox_phase | [[solid]] }}
{{Elementbox_density_gpcm3nrt | 6.24 }}
{{Elementbox_densityliq_gpcm3mp | 5.70 }}
{{Elementbox_meltingpoint | k=722.66 | c=449.51 | f=841.12 }}
{{Elementbox_boilingpoint | k=1261 | c=988 | f=1810 }}
{{Elementbox_heatfusion_kjpmol | 17.49 }}
{{Elementbox_heatvaporiz_kjpmol | 114.1 }}
{{Elementbox_heatcapacity_jpmolkat25 | 25.73 }}
{{Elementbox_vaporpressure_katpa | &nbsp; | &nbsp; | (775) | (888) | 1042 | 1266 | comment= }}
{{Elementbox_section_atomicprop | color1=#cccc99 | color2=black }}
{{Elementbox_crystalstruct | hexagonal }}
{{Elementbox_oxistates | ±2, '''4''', 6<br />(mildly [[acid]]ic oxide) }}
{{Elementbox_electroneg_pauling | 2.1 }}
{{Elementbox_ionizationenergies4 | 869.3 | 1790 | 2698 }}
{{Elementbox_atomicradius_pm | [[1 E-10 m|140]] }}
{{Elementbox_atomicradiuscalc_pm | [[1 E-10 m|123]] }}
{{Elementbox_covalentradius_pm | [[1 E-10 m|135]] }}
{{Elementbox_vanderwaalsrad_pm | [[1 E-10 m|206]] }}
{{Elementbox_section_miscellaneous | color1=#cccc99 | color2=black }}
{{Elementbox_magnetic | nonmagnetic }}
{{Elementbox_thermalcond_wpmkat300k | <br />(1.97&ndash;3.38) }}
{{Elementbox_speedofsound_rodmpsat20 | 2610 }}
{{Elementbox_youngsmodulus_gpa | 43 }}
{{Elementbox_shearmodulus_gpa | 16 }}
{{Elementbox_bulkmodulus_gpa | 65 }}
{{Elementbox_mohshardness | 2.25 }}
{{Elementbox_brinellhardness_mpa | 180 }}
{{Elementbox_cas_number | 13494-80-9 }}
{{Elementbox_isotopes_begin | color1=#cccc99 | color2=black }}
{{Elementbox_isotopes_decay | mn=120 | sym=Te
 | na=0.09% | hl=>2.2&times;10<sup>16</sup>[[year|y]]
 | dm=[[Double electron capture|ε ε]] | de=1.701 | pn=120 | ps=[[tin|Sn]] }}
{{Elementbox_isotopes_decay | mn=121 | sym=Te
 | na=[[synthetic radioisotope|syn]] | hl=16.78 [[day|d]]
 | dm=[[electron capture|ε]] | de=1.040 | pn=121 | ps=[[antimony|Sb]] }}
{{Elementbox_isotopes_stable | mn=122 | sym=Te | na=2.55% | n=70 }}
{{Elementbox_isotopes_decay | mn=123 | sym=Te
 | na=0.89% | hl=>1.0&times;10<sup>13</sup> [[year|y]]
 | dm=[[electron capture|ε]] | de=0.051 | pn=123 | ps=[[antimony|Sb]] }}
{{Elementbox_isotopes_stable | mn=124 | sym=Te | na=4.74% | n=72 }}
{{Elementbox_isotopes_stable | mn=125 | sym=Te | na=7.07% | n=73 }}
{{Elementbox_isotopes_stable | mn=126 | sym=Te | na=18.84% | n=74 }}
{{Elementbox_isotopes_decay | mn=127 | sym=Te
 | na=[[synthetic radioisotope|syn]] | hl=9.35 [[hour|h]]
 | dm=[[beta emission|β<sup>-</sup>]] | de=0.698 | pn=127 | ps=[[iodine|I]] }}
{{Elementbox_isotopes_decay | mn=128 | sym=Te
 | na=31.74% | hl=2.2&times;10<sup>24</sup> [[year|y]]
 | dm=[[Double beta decay|β<sup>&minus;</sup>β<sup>&minus;</sup>]] | de=0.867 | pn=128 | ps=[[xenon|Xe]] }}
{{Elementbox_isotopes_decay | mn=129 | sym=Te
 | na=[[synthetic radioisotope|syn]] | hl=69.6 [[minute|min]]
 | dm=[[beta emission|β<sup>-</sup>]] | de=1.498 | pn=129 | ps=[[iodine|I]] }}
{{Elementbox_isotopes_decay | mn=130 | sym=Te
 | na=34.08% | hl=7.9&times;10<sup>20</sup> [[year|y]]
 | dm=[[Double beta decay|β<sup>&minus;</sup>β<sup>&minus;</sup>]] | de=2.528 | pn=130 | ps=[[xenon|Xe]] }}
{{Elementbox_isotopes_end}}
{{Elementbox_footer | color1=#cccc99 | color2=black }}

'''Tellurium''' ({{pronEng|t<s>ɪ</s>ˈlʊəriəm/, /tɛl-}}) is a [[chemical element]] that has the symbol '''Te''' and [[atomic number]] 52. A brittle silver-white [[metalloid]] which looks like [[tin]], tellurium is chemically related to [[selenium]] and [[sulfur]]. Tellurium is primarily used in [[alloy]]s and as a [[semiconductor]].

== Notable characteristics ==
Tellurium is '''extremely rare''', one of the [[Abundance of the chemical elements|nine rarest elements]] on earth. It is in the same chemical family as [[oxygen]], [[sulfur]], [[selenium]], and [[polonium]] (the [[chalcogen]]s).

When [[crystal]]line, tellurium is silvery-white and when it is in its pure state it has a metallic luster. This is a brittle and easily pulverized metalloid. Amorphous tellurium is found by precipitating it from a solution of tellurous or telluric [[acid]] (Te(OH)<sub>6</sub>). However, there is some debate whether this form is really amorphous or made of minute crystals.

== Applications ==

Tellurium is a p-type [[semiconductor]] that shows a greater conductivity in certain directions which depends on [[atom]]ic alignment. Chemically related to [[selenium]] and [[sulfur]], the conductivity of this element increases slightly when exposed to light ([[photoelectric effect]]). 

It can be doped with [[copper]], [[gold]], [[silver]], [[tin]], or other metals. When in its molten state, tellurium is corrosive to copper, [[iron]], and [[stainless steel]].

Tellurium gives a greenish-blue flame when burned in normal air and forms [[tellurium dioxide]] as a result. 

Metal alloys
*It is mostly used in [[alloy]]s with other metals. It is added to [[lead]] to improve its strength and durability, and to decrease the corrosive action of [[sulfuric acid]]. 
*When added to [[stainless steel]] and [[copper]] it makes these metals more workable. It is alloyed into [[cast iron]] for chill control.

Other uses:
* Used in [[ceramic]]s.
* It is used in [[chalcogenide glass]]es.
* Tellurium is also used in [[blasting cap]]s
* Organic tellurides have also been employed as initiators for living radical polymerisation and electron-rich mono- and di-tellurides possess [[antioxidant]] activity.

High purity [[metalorganics]] of both [[selenium]] and tellurium are used in the semiconductor industry, and are prepared by [[adduct purification]]. <ref>{{doi|10.1016/0022-0248(88)90613-6}} Journal of Crystal Growth Volume 93, Issues 1-4 , 1988, Pages 744-749</ref><ref>{{US patent|5117021}} Method for purification of tellurium and selenium alkyls</ref>

Semiconductor and electronic industry uses:

*Tellurium is used in the media layer of [[CD-RW|ReWritable Compact Discs]] ([[CD-RW]]).

*Tellurium is used in the media layer of [[DVD-RW|ReWritable Digital Video Discs]] ([[DVD-RW]]).

*Tellurium is used in the new [http://www.geek.com/phase-change-memory-from-intel-later-this-year/?rfp=dta phase change memory chips] developed by [[Intel]]. See [[phase change memory]]. Also [http://www.spectrum.ieee.org/print/1501 see here].

*Tellurium is used in the media layer of ReWritable [[Blu-ray dvd|Blu-Ray DVD]]. [http://www.engadget.com/2006/10/19/panasonic-says-that-its-100gb-blu-ray-discs-will-last-a-century/ See here].

*[[Bismuth telluride]] (Bi<sub>2</sub>Te<sub>3</sub>) has found use in [[thermoelectric]] devices.

*Tellurium has potential applications in [[cadmium telluride]] (CdTe) [[Photovoltaic module|solar panel]]s. Some of the highest efficiencies for solar cell electric power generation have been obtained by using this material. [http://www.firstsolar.com First Solar Inc.] started massive commercial production of CdTe solar panels in recent years, significantly increased tellurium demand. If some of the cadmium in CdTe is replaced by [[zinc]] then [[Cadmium zinc telluride|CdZnTe]] is formed which is used in solid-state [[x-ray]] detectors.

*Alloyed with both cadmium and [[mercury (element)|mercury]], to form [[HgCdTe|mercury cadmium telluride]], an [[infrared]] sensitive [[semiconductor]] material is formed. Organotellurium compounds such as [[dimethyl telluride]], [[diethyl telluride]], [[diisopropyl telluride]], [[diallyl telluride]] and [[methyl allyl telluride]] are used as precursors for [[MOVPE]] growth of II-VI [[compound semiconductor]]s. Diisopropyl telluride (DIPTe) is employed as the preferred precursor for achieving the low temperature growth of CdHgTe by [[MOVPE]].

== History ==
Tellurium ([[Latin]] ''tellus'' meaning "earth") was discovered in 1782 by the Hungarian [[Franz-Joseph Müller von Reichenstein]] (Müller Ferenc) in [[Sibiu|Nagyszeben]] (now, Sibiu) [[Transylvania]]. 
In 1789, another Hungarian scientist, Pál Kitaibel, also discovered the element independently, but later he gave the credit to Müller. In 1798, it was named by [[Martin Heinrich Klaproth]] who earlier isolated it.

Tellurium was used as a chemical bonder in the making of the outer shell of the first atom bomb. The 1960s brought growth in thermoelectric applications for tellurium, as well as its use in free-machining [[steel]], which became the dominant use.

==Occurrence==
With an abundance in the Earth's [[crust (geology)|crust]] even lower than [[platinum]], tellurium is, apart from the [[precious metal]]s, the rarest stable solid element in the earth's crust. Its abundance by mass is less than 0.001 [[parts per million|ppm]], compare with 0.037 [[parts per million|ppm]] for [[platinum]]. By comparison, even the rarest of the [[lanthanide]]s have crustal abundances of 0.5 ppm.

The extreme rarity of tellurium in the Earth's crust is not a reflection of its cosmic abundance, which is in fact greater than that of [[rubidium]][http://www.orionsarm.com/science/Abundance_of_Elements.html], even though rubidium is ten thousand times more abundant in the Earth's crust. Rather, the extraordinarily low abundance of tellurium on Earth results from the fact that, during the formation of the Earth, the stable form of elements in the absence of [[oxygen]] and [[water]] was controlled by the oxidation and reduction of [[hydrogen]]. Under this scenario elements such as tellurium which form ''volatile hydrides'' were severely depleted during the formation of the Earth's crust through evaporation. Tellurium and selenium are the heavy elements most depleted in the Earth's crust by this process.

Tellurium is sometimes found in its native (elemental) form, but is more often found as the tellurides of [[gold]] ([[calaverite]], [[krennerite]], [[petzite]], [[sylvanite]], and others). Tellurium compounds are the only chemical compounds of gold found in nature, but tellurium itself (unlike gold) is also found combined with other elements (in metallic salts). The principal source of tellurium is from [[anode]] sludges produced during the electrolytic refining of blister [[copper]]. It is a component of dusts from [[blast furnace]] refining of [[lead]]. Treatment of 500 tons of copper ore [http://www.stda.net/se-te.htm typically yields] one pound of tellurium. Tellurium is produced mainly in the [[US]], [[Canada]], [[Peru]], and [[Japan]]. [http://www.mmta.co.uk/economicsFacts/Articles/MiningJournalReview/Tellurium.pdf See here].

Commercial-grade tellurium is usually marketed as minus 200-[[Mesh (scale)|mesh]] powder but is also available as slabs, ingots, sticks, or lumps.  The year-end price for tellurium in 2000 was [[United States dollar|US$]]14 per pound. In recent years, tellurium price was [http://arizonageology.blogspot.com/2007/05/arizona-tellurium-rush.html driven up] by increased demand and limited supply, reaching as high as [[United States dollar|US$]]100 per pound in 2006. [http://www.resourceinvestor.com/pebble.asp?relid=31031 See also here].

:''See also: [[Telluride, Colorado]], [[:category:Telluride minerals]]''

[[Image:Tellurium crystal.jpg|thumb|Tellurium crystal]]

== Compounds ==
Tellurium is in the same series as [[sulfur]] and [[selenium]] and forms similar compounds. A compound with metal or hydrogen and similar ions is called a [[telluride]]. [[Gold]] and [[silver]] tellurides are considered good ores.  Compounds with tellurate ions complexes TeO<sub>4</sub><sup>2-</sup> or TeO<sub>6</sub><sup>6-</sup> are known as [[tellurate]]s.  Also [[tellurite]]s TeO<sub>3</sub><sup>2-</sup>.  Also tellurols –TeH, named with prefix tellanyl- or suffix -tellurol.
:''See also: [[:Category:Tellurium compounds]]''

== Isotopes ==
{{main|isotopes of tellurium}}
There are 30 known [[isotope]]s of tellurium with [[atomic mass]]es that range from 108 to 137. Naturally found tellurium consists of eight isotopes (listed in the table to the right); three of them are observed to be radioactive. <sup>128</sup>Te has the longest known half-life, 2.2&times;10<sup>24</sup> years, among all radioactive isotopes.{{Fact|date=November 2007}}

== Precautions ==
Tellurium and tellurium compounds should be considered to be mildly [[toxic]] and need to be handled with care.

Acute poisoning is rare.<ref name="Harrison">
{{cite web
  | last = Harrison 
  | first = W
  | authorlink =
  | coauthors = S Bradberry, J Vale
  | title = Tellurium
  | work =
  | publisher = [[International Programme on Chemical Safety]]
  | date = [[1998-01-28]]
  | url = http://www.intox.org/databank/documents/chemical/tellur/ukpid84.htm
  | format = [[HTML]]
  | doi =
  | accessdate = 2007-01-12 }}</ref>
Tellurium is not reported to be carcinogenic.<ref name="Harrison"/>

Humans exposed to as little as 0.01 mg/m<sup>3</sup> or less in air develop "tellurium breath", which has a [[garlic]]-like odor.<ref>
{{cite web
  | last = 
  | first = 
  | authorlink =
  | coauthors = 
  | title = Tellurium
  | work =
  | publisher = [[Los Alamos National Laboratory]]
  | date = [[2003-12-15]]
  | url = http://periodic.lanl.gov/elements/52.html
  | format = [[HTML]]
  | doi =
  | accessdate = 2007-01-12 }}</ref>
The garlic odor that is associated with human intake of tellurium compounds is caused from the tellurium being metabolized by the body. When the body metabolizes tellurium in any oxidation state, the tellurium gets converted into [[dimethyl telluride]]. Dimethyl telluride is volatile and produces the garlic-like smell.

==References==
{{reflist|2}}

{{wiktionary|tellurium}}

== External links ==
{{Commons|Tellurium}}
*[http://www.webelements.com/webelements/elements/text/Te/index.html WebElements.com &ndash; Tellurium]
*[http://minerals.er.usgs.gov/minerals/pubs/commodity/selenium USGS Mineral Information on Selenium and Tellurium]
*[http://www.stda.net/home.htm Selenium Tellurium Development Association]
[[Category:Metalloids]]
[[Category:Chalcogens]]
[[Category:Chemical elements]]
[[Category:Tellurium|*]]

{{Link FA|de}}
<!-- interwiki -->

[[af:Telluur]]
[[ar:تيلوريوم]]
[[az:Tellur]]
[[bn:টেলুরিয়াম]]
[[be:Тэлур]]
[[bs:Telurijum]]
[[bg:Телур]]
[[ca:Tel·luri]]
[[cs:Tellur]]
[[co:Telluriu]]
[[da:Tellur]]
[[de:Tellur]]
[[et:Telluur]]
[[el:Τελλούριο]]
[[es:Telurio]]
[[eo:Teluro]]
[[fr:Tellure]]
[[fur:Teluri]]
[[gl:Telurio (elemento)]]
[[ko:텔루륨]]
[[hy:Տելուր]]
[[hi:टेलुरियम]]
[[hr:Telurij]]
[[io:Telurio]]
[[id:Telurium]]
[[is:Tellúr]]
[[it:Tellurio]]
[[he:טלור]]
[[sw:Teluri]]
[[la:Tellurium]]
[[lv:Telūrs]]
[[lb:Tellur]]
[[lt:Telūras]]
[[jbo:tedjicmu]]
[[hu:Tellúr]]
[[mr:टेलरियम]]
[[nl:Telluur]]
[[ja:テルル]]
[[no:Tellur]]
[[nn:Tellur]]
[[oc:Telluri]]
[[uz:Tellur]]
[[nds:Tellur]]
[[pl:Tellur]]
[[pt:Telúrio]]
[[qu:Teluryu]]
[[ru:Теллур]]
[[scn:Telluriu]]
[[simple:Tellurium]]
[[sk:Telúr]]
[[sl:Telur]]
[[sr:Телур]]
[[sh:Telur]]
[[fi:Telluuri]]
[[sv:Tellur]]
[[ta:டெலூரியம்]]
[[th:เทลลูเรียม]]
[[vi:Telua]]
[[tr:Tellür]]
[[uk:Телур]]
[[zh:碲]]
{{WikiDoc Sources}}