Topics Covered
Chemical Formula
Background
Basic Information
Occurrence
Isotopes
Production
Health Aspects
Key Properties
Applications
References
Chemical Formula
Tc
Background
The existence of technetium was first predicted by the creator of the periodic table, Russian chemist Dmitri Mendeleev.
In 1925, Ida Tacke, Otto Berg, and Walter Noddack of Berlin, Germany claimed they had discovered element 43 (technetium) after testing a number of platinum ores and columbite minerals.
In 1937, technetium was first synthesized by Emilio Segrè in Italy. He analyzed molybdenum which had been exposed to high energy radiation, and discovered that the element was present in it.
Technetium is a silvery-grey metal that slowly tarnishes in moist air.
Basic Information
|
Name |
Technetium |
|
Symbol |
Tc |
|
Atomic number |
43 |
|
Atomic weight |
[ 98 ] |
|
Standard state |
Solid at 298 K |
|
CAS Registry ID |
7440-26-8 |
|
Group in periodic table |
7 |
|
Group name |
None |
|
Period in periodic table |
5 |
|
Block in periodic table |
d-block |
|
Color |
Silvery grey metallic |
|
Classification |
Metallic |
|
Melting point |
2200°C (3992°F) |
|
Boiling point |
4877°C (8811°F) |
|
Density |
11.5 g.cm-3 at 20°C(68°F) |
Occurrence
Technetium occurs naturally in small quantities in uranium ore. The isotope technetium-99 can be produced from waste products of uranium nuclear fuel. Technetium-99m can be produced by neutron activation of molybdenum-98 to form molybdenum-99, which has a half-life of 65.94 h and decays via beta emission to form technetium-99m. This element’s spectral signature has been detected in light.
Technetium (version 1) - Periodic Table of Videos
Isotopes
There are 22 reported isotopes of technetium with mass number ranging from 90 to 111. All the isotopes of technetium are radioactive and not stable. The most stable isotope is 98Tc with a half-life of 4.2 million years.
Production
Technetium can be produced in relatively large quantities from the fission products of uranium nuclear fuel.
Key Properties
The key properties of Technetium are given below:
-
Radioactive
-
Silvery metal
-
Artificially synthesized element
-
Dissolves in nitric acid and concentrated sulfuric acid
-
Not soluble in hydrochloric acid
-
Chemical composition is related to that of rhenium
-
Excellent corrosion inhibitor for steel
-
Excellent superconductor at 11K and below
-
Powder form of this element burns in oxygen to form heptoxide (Tc2O7).
Applications
The most useful isotope of technetium is technetium-99m as it has a short half-life and binds chemically to many biologically active molecules. These properties make it beneficial for several medical radioactive isotope tests.
For example, when Tc-99m is combined with a tin compound, it binds to red blood cells and can be used to map circulatory system disorders.
Technetium-99 is also recommended for use in optolectric nuclear batteries.
The pyrophosphate ion of Tc-99m binds to calcium deposits in damaged heart muscle, thereby making it useful to gauge damage after a heart attack. Similarly the sulfur colloid of Tc-99m is cleaned by the spleen, thus making it possible to image the organ’s structure.
Technetium also acts as a catalyst in specific reactions such as the dehydrogenation of isopropyl alcohol.
References
http://www.webelements.com/technetium/
http://www.chemicool.com/elements/technetium.html
http://www.rsc.org/periodic-table/element/43/Technetium
http://www.lenntech.com/periodic/elements/tc.htm
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