Cadmia (Cadmium range)

It is quite unclear who exactly discovered cadmium, as three men — Friedrich Stromeyer (1776-1835), Johann Christoff Heinrich Roloff (1783-1825) and Karl Samuel Leberecht Hermann (1765-1846) — are credited with discovering the new element in Germany in 1818.

They noticed that, despite the absence of iron or lead, zinc carbonate developed a yellow-to-orange colour when it was “heated to redness”¹.

Cadmium is, in fact, a by-product of the processing of zinc, zinc-bearing lead ores, and complex copper-lead-zinc ores, where it occurs as an impurity in very small quantities:

“Most cadmium-containing ores have from 0.2% to 0.3% cadmium by weight.”²

It was clearly Friedrich Stromeyer, however, who named the new element “Cadmium”, after “Cadmia fornacum Ofenbruch, besonders Ofengalmei der Ockerhütte bei Goslar”³, meaning kiln debris, particularly kiln slag from copper and lead smelting works near Goslar.

Cadmia refers directly to calamine (in Latin⁴), a name then given to zinc galmei (zinc ore), a by-product of lead and silver production⁵.

The word cadmia itself derives from the Greek Καδμεία (Kadmeia), as in Καδμεία γη (Kadmeia ge, the land or earth of Cadmus)⁶, referring to the acropolis of ancient Thebes in Greece. Its founder and king was the great Greek hero Cadmus (Κάδμος, Cadmus), brother of Europa (Ευρώπη).

Cadmus was closely associated with metallurgy in ancient Greece⁷, hence the significance of Thebes in the history of ancient metallurgy⁸.

Stromeyer was also the first to propose cadmium compounds for use as pigments⁹.

Cadmium yellows were in use in Germany by 1829, in France by 1831, in North America by 1842, and in the United Kingdom by 1846. Cadmium red became available in Germany in 1907, England 1912 and the U.S.A. in 1919¹⁰, following the identification of selenium by the Swedish chemist Jöns Jacob Berzelius (1779–1848) and its subsequent use as an essential component of cadmium reds¹¹.