Element Tellurium

Tellurium ElementIt is a chemical element with the symbol Te and atomic number 52.
It is a brittle, mildly toxic, rare, silver-white metalloid. Element Tellurium is chemically related to selenium and sulfur, all three of which are chalcogens. It is occasionally found in native form as elemental crystals.
Element Tellurium is far more common in the Universe as a whole than on Earth. Its extreme rarity in the Earth’s crust, comparable to that of platinum, is due partly its formation of a volatile hydride that caused tellurium to be lost to space as a gas during the hot nebular formation of Earth, and partly to tellurium’s low affinity for oxygen that causes it to bind preferentially to other chalcophiles in dense minerals that sink into the core.
Tellurium adopts a polymeric structure consisting of zig-zag chains of Te atoms. This gray material resists oxidation by air and is not volatile.

Names and Identifiers

Chemical Formula:Te
CAS:13494-80-9
Molecular Weight:127.600 g/mol
EC Number :236-813-4
MDL Number:MFCD00134062
Color:silvery lustrous gray/ silvery
Other Names:Tellur, Telúrio
PubChem CID:6327182
IUPAC Name:Tellurium
Inchl:InChI=1S/Te
InChI Key:PORWMNRCUJJQNO-UHFFFAOYSA-N
Canonical SMILES:[Te]
ICSC Number:1325

Physical & Chemical Properties

Phase:Solid
Density:6.24 g/cm³
Boiling Point:1261 K ​(988 °C, ​1810 °F)
Melting Point:722.66 K ​(449.51 °C, ​841.12 °F)
Molecular Formula:Te
Flash Point:n/a
Exact Mass:129.906219
Symbol:Globally Harmonized System of ClassificationGlobally Harmonized System of Classification
Signal Word:Danger
Hazard Statements:H317-H332-H360-H412
Precautionary Statements:P201-P261-P280-P308 + P313
Hazard Codes:T:Toxic
Risk Phrases:R25
Safety Phrases:S45
RIDADR:UN 3288 6.1/PG 3
WGK Germany:3
RTECS:WY2625000
Packaging Group:III
Hazard Class:8

Tellurium has eight stable isotopes (Te-120 and Te-123 are usually considered stable because of their long half lives) and many of them have a medical application.

Te-120 is used for the production of I-120g which has an application as a PET and Beta emitting isotope. Te-122 is used in the production of the radioisotope I-122 which is used in gamma imaging. Te-123 is used for the production of radioactive I-123 which is used in thyroid imaging. Te-124 is used for the production of both I-123 and the PET isotope I-124. Finally, Te-130 is used in the research into double Beta decay.

Naturally occurring isotopes

IsotopeMass/DaNatural abundance (atom %)Nuclear spin (I)Magnetic moment (μ/μN)
120Te119.904048 (21)0.09 (1)0
122Te121.903050 (3)2.55 (12)0
123Te122.9042710 (22)0.89 (3)1/2-0.73679
124Te123.9028180 (18)4.74 (14)0
125Te124.9044285 (25)7.07 (15)1/2-0.88828
126Te125.9033095 (25)18.84 (25)0
128Te127.904463 (4)31.74 (8)0
130Te129.906229 (5)34.08 (62)0

Radiosotope data

IsotopeMass/DaHalf-lifeMode of decayNuclear spinNuclear magnetic moment
116Te115.90842.49 hEC to 116Sb0
117Te116.908641.03 hEC to 117Sb1/2
118Te117.905836.00 dEC to 118Sb0
119Te118.9064116.0 hEC to 119Sb1/20.25
121Te120.9049416.8 dEC to 121Sb1/2
127Te126.9052179.4 hβ to 127I3/20.64
129Te128.90659633.6 dβ to 129I3/20.70

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