Tantalum

Today I´m going to talk about tantalum

Tantalum is a greyish silver, heavy, and very hard metal. When pure, it is ductile and can be drawn into fine wire, which can be 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.

Table: basic information about and classifications of tantalum.

Name: Tantalum Symbol: Ta Atomic number: 73 Atomic weight: 180.94788 (2) Standard state: solid at 298 K CAS Registry ID: 7440-25-7

Group in periodic table: 5 Group name: (none) Period in periodic table: 6 Block in periodic table: d-block Colour: grey blue Classification: Metallic

 Small and large samples of tantalum wire like this, as well as foil, sheet, insulated wire, mesh and rod, can be purchased via their web catalogue from Advent Research Materials via their web catalogue.

Tantalum: historical information

Tantalum was discovered by Anders Ekeberg at 1802 in Sweden. Origin of name: from the Greek word "Tantalos" meaning "father of Niobe" (Greek mythology, (tantalum is closely related to niobium in the periodic table).

                                            

 

 

 

 

 

 

 

 

 

Niobium was discovered in 1802 by Anders Gustaf Ekeberg, but many chemists thought niobium and tantalum were one and the same. Some felt that perhaps tantalum was an allotrope of niobium. Later, Rose, in 1844, and Marignac, in 1866, showed that niobic and tantalic acids were two different acids.

The first relatively pure tantalum was produced by von Bolton in 1907.

Tantalum: physical properties

• Melting point: 3290 [or 3017 °C (5463 °F)] K
• Boiling point: 5731 [or 5458 °C (9856 °F)] K
• Density of solid: 16650 kg m^-3

 

Tantalum: orbital properties

• Ground state electron configuration:  [Xe].4f¹⁴.5d³.6s²
• Shell structure:  2.8.18.32.11.2
• Term symbol:   ⁴F_3/2
• Pauling electronegativity: 1.5 (Pauling units)
•  First ionisation energy: 761 kJ mol^-1
•  Second ionisation energy: 1500 kJ mol^-1

 

Isolation

Isolation: isolation of tantalum appears to be complicated. Tantalum minerals usually contain both niobium and tantalum. Since they are so similar chemically, it is difficult to separate them. Tantalum can be extracted from the ores by first fusing the ore with alkali, and then extracting the resultant mixture into hydrofluoric acid, HF. Current methodology involves the separation of tantalum from these acid solutions using a liquid-liquid extraction technique. In this process tantalum salts are extracted into the ketone MIBK (methyl isobutyl ketone, 4-methyl pentan-2-one). The niobium remains in the HF solution.

After conversion to the oxide, metallic tantalum can be made by reduction with sodium or carbon. Electrolysis of molten fluorides is also used.