During this process, chromium sulfate is used to treat animal skin and turn it into leather that is resistant to hot water that can cause degradation. Kilns and furnaces use bricks made of chromite ore, which retains strength at high temperatures. The textile industry uses chromium ions to help adhere dyes to fabric. Chromium's high melting point, moderate thermal expansion and crystalline structure stability make it suitable for these purposes.
Though its specific role in humans is unclear, studies have shown that chromium is an essential trace element that is found in RNA and helps the body to use glucose. Chromium is most concentrated in the placenta, and its presence in the body decreases with age.
A safe amount is about 1 milligram per day, according to the RSC. Foods such as brewer's yeast, wheat germ and kidney are rich in chromium. However, it is poisonous in excess. In the film "Erin Brockovich," Julia Roberts portrays an environmental activist and legal clerk who leads a case against a gas and electric company for contaminating drinking water with chromium VI , a toxic compound known to cause cancer , according to the U.
Potassium dichromate K 2 Cr 2 O 7 is used in the tanning of leather while other chromium compounds are used as mordants, materials which permanently fix dyes to fabrics.
Chromium compounds are also used to anodize aluminum, a process which coats aluminum with a thick, protective layer of oxide. Chromite, chromium's primary ore, is used to make molds for the firing of bricks because of its high melting point, moderate thermal expansion and stable crystal structure. Estimated Crustal Abundance : 1. Number of Stable Isotopes : 3 View all isotope data. Electron Shell Configuration :. In fact, the name chromium is from the Greek word " chroma " meaning " colour ", so named because of the many different coloured compounds displayed by chromium.
A year or two after Vauquelin's discovery, a German chemist named Tassaert working in Paris found chromium in an ore now called chromite. This ore, Fe CrO 2 2 , is now an important source of chromium.
A measure of how difficult it is to deform a material. It is given by the ratio of the shear stress to the shear strain. A measure of how difficult it is to compress a substance. It is given by the ratio of the pressure on a body to the fractional decrease in volume. A measure of the propensity of a substance to evaporate. It is defined as the equilibrium pressure exerted by the gas produced above a substance in a closed system.
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Jump to main content. Periodic Table. Glossary Allotropes Some elements exist in several different structural forms, called allotropes. Discovery date Discovered by Nicholas Louis Vauquelin Origin of the name The name is derived from the Greek 'chroma', meaning colour. Glossary Group A vertical column in the periodic table. Fact box. Glossary Image explanation Murray Robertson is the artist behind the images which make up Visual Elements.
Appearance The description of the element in its natural form. Biological role The role of the element in humans, animals and plants. Natural abundance Where the element is most commonly found in nature, and how it is sourced commercially.
Uses and properties. Image explanation. Chromium plating can be used to give a polished mirror finish to steel. Chromium-plated car and lorry parts, such as bumpers, were once very common.
It is also possible to chromium plate plastics, which are often used in bathroom fittings. However, the waste effluent is toxic so alternatives are being investigated. Chromium compounds are used as industrial catalysts and pigments in bright green, yellow, red and orange colours.
Rubies get their red colour from chromium, and glass treated with chromium has an emerald green colour. Biological role. Chromium is an essential trace element for humans because it helps us to use glucose.
However, it is poisonous in excess. We take in about 1 milligram a day. Natural abundance. Chromium is found mainly in chromite. Chromium metal is usually produced by reducing chromite with carbon in an electric-arc furnace, or reducing chromium III oxide with aluminium or silicon. Help text not available for this section currently. Elements and Periodic Table History. He was intrigued by a bright red mineral that had been discovered in a Siberian gold mine in and was referred to as Siberian red lead.
It is now known as crocoite and is a form of lead chromate. Vauquelin analysed it and confirmed that it was a lead mineral. Then he dissolved it in acid, precipitated the lead, filtered this off, and focused his attention on the remaining liquor from which he succeeded in isolating chromium. Intrigued by the range of colours that it could produce in solution, he named it chromium from the Greek word chroma meaning colour.
He then discovered that the green colouration of emeralds was also due to chromium. Atomic data. Glossary Common oxidation states The oxidation state of an atom is a measure of the degree of oxidation of an atom. Oxidation states and isotopes. Glossary Data for this section been provided by the British Geological Survey.
Relative supply risk An integrated supply risk index from 1 very low risk to 10 very high risk. Recycling rate The percentage of a commodity which is recycled.
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