Tantalum

Category: transition metal Atomic number: 73 Colour: blueish grey Melting point: 3,017°C (5,463°F) Boiling point: 5,458°C (9,856°F) First identified: 1802

The Swedish chemist Anders Gustav Ekeberg identified tantalum in 1801, but there were many years of confusion over the similarity between tantalum and its upstairs neighbour niobium, before they were confirmed as separate elements. They almost always appear together in ‘coltan’, which is the name for any combination of columbite (a niobium-rich ore) and tantalite (which is rich in tantalum). Due to its stubborn resistance to reactions, it was named after the mythological Greek king Tantalus, who was punished for stealing from the gods by being forced to stand in a pool of water that would forever evade his attempts to drink it.

Tantalum is widely used in mobile phones and other handheld devices, such as games consoles and digital cameras. Capacitors, made of tantalum and its oxide, store up charge and electricity – the element is an excellent conductor of heat and electricity, so can be made into components that provide high capacitance at a very small size. It is unlikely that our current devices would be so miniaturized if it weren’t for tantalum.

Among the metals, only tungsten and rhenium have higher melting points, so its alloys are used in hot places, such as aeroplane engines and nuclear reactors. And because it is so chemically inert, it has many medical applications – including in surgical instruments, implants such as pacemakers, and foil, gauze or wire for repairing nerves and muscles.

The high demand for tantalum in recent years has led to political controversy. Following the closure of a major mine in Australia during the economic downturn, the main source of the element now is the Democratic Republic of Congo, where profits from it helped to fund the dreadful civil war and continue to be tainted by corruption and political strife (leading some to denounce it as ‘blood tantalum’).