Chromium is a chemical element that belongs to Group VIB in the periodic table. The element name comes from Greek, which means "color" because chromium compounds have colors. The element is a steel-gray metal and is the hardest metal in nature. The content of chromium in the earth's crust is 0.01%, ranking 17th. Natural chromium in free form is extremely rare and mainly exists in chromite.

Chromium has the following uses:

Alloy preparation: 
Chromium is widely used as an alloy additive, especially alloys formed with iron and nickel, such as stainless steel, heat-resistant alloys and magnetic materials. Stainless steel contains at least 10.5% chromium, which makes it corrosion-resistant and high-temperature resistant.

Electroplating: 
Chromium is used in the electroplating process to provide corrosion protection and decorative effects on metal surfaces.

Pigments and dyes: 
Chromium compounds are often used in pigment preparation and dye industries, such as chrome yellow and chrome green.

Preservatives and catalysts: 
Chromates are used as oxidants, catalysts and preservatives, and are widely used in chemical laboratories and industries.
It should be noted that high concentrations of hexavalent chromium are toxic to the human body and can cause damage to the respiratory system, skin and digestive system. However, trivalent chromium is involved in glucose metabolism in the body and is essential to human health.