History of Chromium Goes Back to Tarracotas

The history of chromium dates back thousands of years. Weapons found in burial pits dating from the late 3rd century BC Qin Dynasty of the Terracotta Army near Xi’an, China have been analyzed by archaeologists. Although buried more than 2,000 years ago, the ancient bronze tips of crossbow bolts and swords found at the site showed no sign of corrosion, because the bronze was coated with chromium.[2]

Crocoite (PbCrO4)

Chromium came to the attention of westerners in the 18th century. On 26 July 1761, Johann Gottlob Lehmann found an orange-red mineral in the Ural Mountains which he named Siberian red lead. Though misidentified as a lead compound with selenium and iron components, the material was lead chromate with a formula of PbCrO4, now known as the mineral crocoite.[3]

In 1770, Peter Simon Pallas visited the same site as Lehmann and found a red lead mineral that had useful properties as a pigment in paints. The use of Siberian red lead as a paint pigment developed rapidly. A bright yellow made from crocoite also became fashionable.[citation needed]

In 1797, Louis Nicolas Vauquelin received samples of crocoite ore. He produced chromium oxide (CrO3) by mixing crocoite with hydrochloric acid. In 1798, Vauquelin discovered that he could isolate metallic chromium by heating the oxide in a charcoal oven.[4] He was also able to detect traces of chromium in precious gemstones, such as ruby, or emerald.[citation needed]

During the 1800s, chromium was primarily used as a component of paints and in tanning salts, but metal alloys now account for 85% of the use of chromium. The remainder is used in the chemical industry and refractory and foundry industries. Chromium is also known well for its luster when polished. It is used for decoration, etc.[citation nee

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