Periodic Table


Atomic number: 73
Atomic weight: 180.9479
Symbol: Ta
Group number: 5
Electronic configuration: [Xe].4f14.5d3.6s2


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 (Rmax)
orbital s p d f
radius170.9no data82.023.1


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


This section gives some data for naturally occurring isotopes.
Nominal mass Accurate mass % natural abundance
180Ta179.947462 (4)0.012 (2)
181Ta180.947992 (3)99.988 (2)

Further Information

Copyright 1997 Mark Winter
Department of Chemistry at the University of Sheffield, Sheffield S3 7HF, England.

The current version of this document is at http://www.shef.ac.uk/~chem/web-elements-I/Ta.html