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Cr
24
Mn
25
Fe
26
Mo
42
Tc
43
Ru
44
W
74
Re
75
Os
76

 

Periodic table

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Technetium

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Technetium

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Technétium

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Tehnecij

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Tecneto

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Tecnecio

 

Tc
Tc
Technetium

PERIODIC TABLE OF THE ELEMENTS

TECHNETIUM

TRANSITION ELEMENT:
MANGANESE GROUP

 

Atomic number:43

Group numbers:7

Period:5

Electronic configuration:[Kr] 4d6 5s1

Formal oxidation number:+4 +6 +7

Electronegativities:2.1

Atomic radius / pm:135.2

Relative atomic mass:[98]

 

Technetium was discovered by Carlo Perrier (IT) and Emilio Segré (US) in 1937. The origin of the name comes from the Greek word technikos meaning artificial. It is a silvery-grey metal that resists oxidation but tarnishes in moist air and burns in high oxygen environment. Technetium is the first synthetically produced element. It is also radioactive. Technetium is made by bombarding molybdenum with deuterons (heavy hydrogen) in a cyclotron. Added to iron in quantities as low as 55 part-per-million transforms the iron into a corrosion-resistant alloy.

PHYSICAL PROPERTIES

Density / g dm-3:11500 (est., 293 K)

Molar volume / cm3mol-1:8.52 (est., 293 K)

Electrical resistivity / μΩcm:16.9 (20 °C)

THERMAL PROPERTIES

Thermal conductivity / W m-1K-1:50.6

Melting point / °C:2157

Boiling point / °C:4265

Heat of fusion / kJ mol-1:23.81

Heat of vaporization / kJ mol-1:585.22

Heat of atomization / kJ mol-1:678

IONIZATION ENERGIES

First ionization energy / kJ mol-1:702.42

Second ionization energy / kJ mol-1:1472.38

Third ionization energy / kJ mol-1:2850.20

ABUNDANCE OF ELEMENTS

in the atmosphere / ppm:-

in the Earth's crust / ppm:-

in the oceans / ppm:-

CRYSTALLOGRAPHIC DATA

hexagonal

Crystal structure:

hexagonal

Unit-cell dimensions / pm:

a=274.3, c=440.0

Space group:

P63/mmc

ISOTOPES

IsotopeRelative atomic massMass percent (%)
98Tc97.907216(4)*
99Tc98.906255(2)*

REDUCTION POTENTIALS

Balanced half-reaction Eo / V

 

42 Molybdenum <=
43 Technetium
=> 44 Ruthenium