Later that year, in Spain, the brothers succeeded in isolating tungsten by reduction of this acid with charcoal, and they are credited with the discovery of the element.

At first, crocoite from Russia was the main source, but in 1827, a larger chromite deposit was discovered near Baltimore, United States.

This made the United States the largest producer of chromium products until 1848 when large deposits of chromite where found near Bursa, Turkey.

[13] For about a century after its isolation, molybdenum had no industrial use, owing to its relative scarcity, difficulty extracting the pure metal, and the immaturity of the metallurgical subfield.

[14][15][16] Early molybdenum steel alloys showed great promise in their increased hardness, but efforts were hampered by inconsistent results and a tendency toward brittleness and recrystallization.

In 1906, William D. Coolidge filed a patent for rendering molybdenum ductile, leading to its use as a heating element for high-temperature furnaces and as a support for tungsten-filament light bulbs; oxide formation and degradation require that moly be physically sealed or held in an inert gas.

During the first World War, demand for molybdenum spiked; it was used both in armor plating and as a substitute for tungsten in high-speed steels.

Portugal, as the main European source of the element, was put under pressure from both sides, because of its deposits of wolframite ore at Panasqueira.

Tungsten's resistance to high temperatures and its strengthening of alloys made it an important raw material for the arms industry.

It is mainly mined in the United States, China, Chile, and Peru, with the total amount produced being 200,000 tonnes per year.

[23] Seaborgium is a radioactive synthetic element that is not found in nature; the most stable known isotope has a half-life of approximately 14 minutes.

In contrast, and unusually for a first-row d-block transition metal, chromium appears to have few biological roles, although it is thought to form part of the glucose metabolism enzyme in some mammals.