tantalum

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

Description

Tantalum is a grey, heavy, and very hard metal. When pure, it is ductile and can be drawn into fine wire, which is used as a filament for evaporating metals such as aluminium. Tantalum is almost completely immune to chemical attack at temperatures below 150°C, and is attacked only by hydrofluoric acid, acidic solutions containing the fluoride ion, and free sulphur trioxide. The element has a melting point exceeded only by tungsten and rhenium.

General information

Discoveror: Anders Ekeberg
Date discovered: 1802
Discovered at: Sweden
Meaning of name: From the Greek word "Tantalos" meaning "father of Niobe" (Greek mythology, (tantalum is closely related to niobium in the periodic table)

Physical data

Standard state: solid at 298 K
Colour: grey blue
Density of solid at ambient temperature/kg m^-3: 16650
Molar volume/cm³: 10.85

Radii /pm

Atomic: 200
Covalent (single bond):
Pauling radius for the ion [Ta]^-: no data

Valence shell orbital radius maxima (R_max)

orbital	s	p	d	f
radius	170.9	no data	82.0	23.1

Electronegativities

Both values are quoted on the Pauling scale.

Pauling: 1.5
Allred Rochow: 1.33

Crystal Structure

structure: bcc (body-centred cubic)

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: 3290
boiling point: 5731

Enthalpies /kJ mol^-1

fusion: 36.6
vaporization: 735

single bond enthalpies:

Ta-F	Ta-Cl	Ta-Br	Ta-I	Ta-Ta
no data	no data	no data	no data	no data

Ionization enthalpies /kJ mol^-1

Number	Enthalpy
1st	761

Isotopes

This section gives some data for naturally occurring isotopes.

Nominal mass	Accurate mass	% natural abundance
180Ta	179.947462 (4)	0.012 (2)
181Ta	180.947992 (3)	99.988 (2)

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