technetium

• Description
• General information
• Physical data
• Radii
• Electronegativities
• Solid state structure
• Temperatures
• Enthalpies
• Ionization Enthalpies
• Isotopes
• Further information

Description

Since its discovery, searches for the element technetium in terrestrial materials have been made without success. Technetium has been found in the spectrum of S-, M-, and N-type stars, and its presence in stellar matter is leading to new theories of the production of heavy elements in the stars.

Technetium is a silvery-grey metal that tarnishes slowly in moist air. Until 1960, technetium was available only in small amounts. The chemistry of technetium is related to that of rhenium.

General information

Discoveror: Carlo Perrier, Emilio Segre
Date discovered: 1937
Discovered at: Italy
Meaning of name: From the Greek word "technikos" meaning "artificial"

Physical data

Standard state: solid at 298 K
Colour: silvery grey metallic
Density of solid at ambient temperature/kg m^-3: 11500
Molar volume/cm³: 8.63

Radii /pm

Atomic: 183
Covalent (single bond):
Pauling radius for the ion [Tc]^-: no data

Valence shell orbital radius maxima (R_max)

orbital	s	p	d	f
radius	157.4	no data	66.8	no data

Electronegativities

Both values are quoted on the Pauling scale.

Pauling: 1.9
Allred Rochow: 1.36

Crystal Structure

structure: hcp (hexagonal close-packed)

The following CrystalMaker image represents the solid state structure. For most elements, the most stable allotrope is illustrated. Try WebElements version 2 for interactive virtual reality and CHIME images.

Temperatures (/K)

melting point: 2430
boiling point: 4538

Enthalpies /kJ mol^-1

fusion: 23.8
vaporization: 540

single bond enthalpies:

Tc-F	Tc-Cl	Tc-Br	Tc-I	Tc-Tc
no data	no data	no data	no data	no data

Ionization enthalpies /kJ mol^-1

Number	Enthalpy
1st	702
2nd	1472
3rd	2850

Isotopes

This section gives some data for naturally occurring isotopes.

Nominal mass	Accurate mass	% natural abundance
		nil

Further Information

• Additional information about WebElements 1.2.2
• This is a licensed copy (here is the full list) of WebElements 1.2.2 and contains a subset of the material contained within the main version of WebElements (version 2)
• For further information please try WebElements version 2
• Sheffield Chemdex: perhaps the largest internet chemistry directory
• Sheffield Chemputer: interactive chemistry calculators on the WWW