Niobium

Category: transition metal Atomic number: 41 Colour: dull grey Melting point: 2,477°C (4,491°F) Boiling point: 4,744°C (8,571°F) First identified: 1801

You may have noticed that there are particular periods of time in which the discovery of new elements accelerated. One was following the publication of Mendeleev’s periodic table, as chemists started to search for the ‘missing elements’. And earlier, at the end of the eighteenth century, Lavoisier’s law of conservation of mass (1789) and Proust’s law of definite proportions (1799) provoked John Dalton to formulate atomic theory and awakened a wider interest in the idea of ‘elements’.

All this was part of the inspiration for the discovery of niobium – in 1801, the chemist Charles Hatchett started to ponder a specimen of the mineral columbite in the British Museum. His experiments led him to believe that it contained a new element, which he named columbium. Others subsequently doubted his findings, suggesting it was tantalum (which was separately discovered the following year). However, in 1844, the German chemist Heinrich Rose proved that columbite contained two elements (tantalum and niobium, which he named after Niobe, the daughter of King Tantalus in Greek mythology). The pure metal was finally isolated in 1864.

It is a steely grey metal that is highly resistant to corrosion, as it forms a tough oxide layer. It is used in many alloys, especially stainless steel, and improves the strength of alloys that are to be used at low temperatures. It has also been used in rocket and jet engines, in oil rigs and gas pipelines.

American scientists continued to use the name columbium right up until 1950 – the controversy was only settled when an agreement was reached to take the European name for niobium, and the American name for tungsten (as opposed to the European ‘wolfram’), though some US metallurgists, even today, still insist on using the name columbium.

It was tungsten (see here) that robbed niobium of a more prominent everyday role in our lives: niobium was the metal originally used for the filaments of incandescent lightbulbs, due to its high melting point, but it was soon replaced by tungsten, which melts at even higher temperatures.