THE HISTORY OF AN IDEA · 1781–1928
Metals that will not melt
Tungsten, molybdenum, tantalum, niobium and hafnium were hard to discover for the same reason they became indispensable: their compounds are stubborn and the metals themselves resist heat.
Explore the supporting references at the foot of this article.
01
Oxides that will not give up their metal
Scheele showed in the early 1780s that molybdenite and the then called tungsten each contained a new acid-forming , but obtaining the metals required at temperatures beyond the ordinary furnace, and the products came out as powders contaminated with carbon. Hjelm reduced molybdenum in 1781 and the Elhuyar brothers tungsten in 1783, in both cases with charcoal at high temperature. Because these metals melt far above iron, the eighteenth-century sequence of smelt, melt and cast simply did not apply to them.
02
Two elements confused for forty years
Hatchett found a new element in a mineral in the British Museum in 1801 and called it columbium; Ekeberg found tantalum in Finnish minerals in 1802; and because the two elements occur together and behave almost identically, most chemists concluded they were the same substance. Rose separated them again in 1846 and named the lighter one niobium. The confusion is the point: chemical similarity between neighbors in the same group can be strong enough to hide an element in plain sight, and it took careful fractional separation to undo.
03
A metal made workable, and a gap closed by X-rays
Tungsten’s industrial career began not with its discovery but with Coolidge’s demonstration in 1910 that sintered tungsten could be worked into wire if it was mechanically processed in the right temperature sequence, which gave the incandescent lamp its filament and later gave X-ray tubes their targets. Hafnium, meanwhile, was the last of the group to appear: Coster and Hevesy found it in 1923 in zirconium minerals, guided by Moseley’s X-ray method and by the argument that element 72 should be a transition metal rather than a rare earth.
What followed
These metals now carry the highest-temperature duties in lighting, cutting tools, turbine and furnace hardware, capacitors and nuclear components, and their extraction still depends on chemical routes rather than melting.
USGS — BerylliumLANL Periodic Table — BerylliumRSC Periodic Table — BerylliumUSGS — TechnetiumLANL Periodic Table — Tungsten
Sources & further reading
- USGS — Beryllium ↗United States Geological SurveyReference explanation · Source checked
- LANL Periodic Table — Beryllium ↗Los Alamos National LaboratoryReference explanation · Source checked
- RSC Periodic Table — Beryllium ↗Royal Society of ChemistryReference explanation · Source checked
- USGS — Technetium ↗United States Geological SurveyReference explanation · Source checked
- LANL Periodic Table — Tungsten ↗Los Alamos National LaboratoryReference explanation · Source checked
Sources and further reading. What the review labels mean