Have you heard of the terracotta army of the Qin dynasty? It is a large collection of terracotta sculptures prepared to be buried along with the Chinese emperor when he died in the 3rd century BC. He would be protected by them in his after-life, they thought!
Now, what should interest us are not the sculptures themselves, but the presence of an element which the modern world came to know about only in the late 18th century, namely chromium. The weapons of this army were tipped with chromium oxide so that they stayed without rusting for millennia! Chromium was primarily used to produce some highly sought after pigments of red and yellow.
The precious ruby stone gets its natural red colour from chromium. Chromium has a silvery, shiny appearance, and is a favourite substance to coat cars, and other appliances to protect them from corrosion and to improve their looks.
Chromium is generally found in its ores. It is rarely found in its pure form in nature. The most common ore from which chromium is extracted is chromite. Some forms of chromium are non-toxic. However, chromium (VI) is carcinogenic. The discoverer of chromium is Nicolas L. Vauquelin, who achieved the feat in 1797.
Its atomic number is 24 and the atomic symbol is Cr.
