Facts about the element technetium (masurium)

Identification of the chemical element technetium (Tc) formerly known as Masurium.

Atomic number:  43

Symbol:  Tc

Atomic Weight:  98.9072

Discovery:  Carlo Perrier and Emilio Segre (1937, Italy) found it in a sample of molybdenum that had been bombarded with neutrons; it had previously been named by Noddack, Tacke and Berg in 1924 as a masurium .

The electronic configuration is:  [Kr] 5s  ²  4d  ⁵

Origin of the word:  It comes from the Greek  technikos : set of resources that are used in an art, science or activity and  technetos : artificial. Technetium was the first artificially manufactured element.

Isotopes:  Twenty-one isotopes of Technetium are known, with atomic masses ranging from 90-111. Tc is one of the elements with Z < 83 without stable isotopes; all technetium isotopes are radioactive. (The other radioactive chemical element is promethium.) Some isotopes are produced as fission products of uranium.

Properties: Technetium is a silvery-gray metal that oxidizes slowly in humid air, that is, in the presence of oxygen. Common oxidation states are +7, +5, and +4. The chemistry of technetium is similar to that of rhenium (Re). Technetium is a corrosion inhibitor for steel and is an excellent superconductor at temperatures 11K and below.

Uses: Technetium-99 is used in many medical tests for radioactive isotopes. Mild carbon steels can be effectively protected with trace amounts of technetium, but this corrosion protection is limited to closed systems due to technetium radioactivity and therefore must be confined to an isolated location.

Element Classification:  It is classified as a transition metal.

Chemical and physical properties of Technetium (Tc)

Density (g/cc):  11.5

Melting point (K):  2445

Boiling point (K):  5150

Appearance:  silver gray metal

Atomic radius (picometer):  136

Covalent radius (picometer):  127

Ionic radius(picometer):  56 (+ 7e)

Atomic Volume (cc/mol):  8.5

Specific heat (@ 20°CJ/g mol):  0.243

Heat of Fusion (kJ/mol):  23.8

Heat of Evaporation (kJ/mol):  585

Pauling Negativity Number:  1.9

First ionizing energy (kJ/mol):  702.2

Oxidation States:  7

Lattice Structure:  Hexagonal

Lattice constant (Å):  2.740

Lattice C/A Ratio:  1.604 

Fountain:

• CRC Handbook of Chemistry and Physics (18th Ed.)
• Crescent Chemical Company (2001)
• Lange’s Handbook of Chemistry (1952)
• Los Alamos National Laboratory (2001)