What is Cerium

Cerium (pronunciation: SER-ee-em) is a soft, grayish metal that belongs to the group of lanthanides and is represented by the chemical symbol Ce ^{[1, 2]}. Its naturally-occurring isotopes include Cerium-136, Cerium-138, Cerium-140, and Cerium-142, out of which Cerium-140 is the most abundant (with 88.48% natural abundance) ^[3]. Among the 35 known radioisotopes of cerium, the most stable is Cerium-144 that is characterized by a half-life period of 284.893 days ^[3].

Where is Cerium Found

Cerium is commonly found in rare earth minerals like bastnaesite and monazite ^[1]. The mineral ore is heated and then treated with hydrochloric acid to produce cerium oxide from which metallic cerium is isolated through electrochemical reduction ^[1]. The metal can also be obtained through thermal reduction of cerium fluoride with calcium ^{[1, 4]}. While China, the CIS countries, and the USA have the highest cerium reserves, the top 3 cerium producing countries in the world are China, Russia, and Malaysia ^[1].

History

Origin of its Name: It is named after ‘Ceres’, an asteroid that was named after the Roman goddess of fertility and agriculture ^[1].

Who discovered it: The element was discovered by the Swedish chemists, Jöns Jacob Berzelius along with Wilhelm von Hisinger, and independently by the German chemist Martin Klaproth ^{[1, 4]}.

When and How was it Discovered

In 1803, Berzelius and Hisinger discovered the new element from a reddish-brown cerium salt called cerite ^{[1, 5]}. While investigating the chemical reaction of the cerium salts, they found the two oxidation states – one of which producing yellowish-red salts and the other colorless ones ^[5]. Although they did not isolate the pure form, they named the element ‘cerium’ and its oxide ‘ceria’ ^[5].

Martin Klaproth analyzed the salt and concluded that it consists of an oxide of a new metallic element ^[5]. He named the oxide ‘ockroite’ because of its yellowish-red color ^[5]. However, the result of Berzelius and Hisinger was published before that of Klaproth, and so the name cerium was approved ^[5].

Cerium Identification
Atomic number	58 [1]
CAS number	7440-45-1 [1]
Position in the periodic table	Group	Period	Block
	Lanthanides [1]	6 [1]	f [1]

Properties and Characteristics of Cerium

Atomic Data of Cerium (Element 58)

What is It Used for

• The mischmetal alloy made of cerium, lanthanum, neodymium, and praseodymium mixed with magnesium oxide and iron oxide is used as flints for lighting cigarettes and gas ^{[1, 5]}.
• Cerium oxide, as a catalyst, is used in self-cleaning ovens for preventing the accumulation of cooking residues and for polishing glass surfaces ^{[1, 5]}.
• It is used in catalytic converters because it helps reduce automobile exhaust emissions ^[1]. Cerium oxide nanoparticles are added to diesel for reducing the emission of soot and improving engine performance of vehicles ^[5].
• Cerium sulfide is non-toxic by nature and is used as a coloring pigment because of its rich red color ^[1].
• The element is used in phosphors in flat-screen televisions, floodlights, and energy-efficient light bulbs ^[1].
• Flammacerium, a compound containing cerium nitrate and silver sulfadiazine, is a topical ointment used for treating infections in burn wounds ^[5].

Cerium Toxicity

The element 58 has no known biological roles and is low to moderate in toxicity ^{[1, 5]}.

Interesting Facts

• The image of cerium is a graphical representation of the asteroid Ceres, whereas the background is derived from an astronomical map of the 17th-century ^[1].
• Its natural abundance is almost similar to zinc, but it is more than lead or tin ^[1].
• At room temperature, the element can readily oxidize ^[4].
• Pure cerium may ignite if scratched with a sharp metal object such as a knife ^[4].
• It decomposes in water to produce cerium hydroxide and hydrogen ^[5].

Cost of Cerium

The cost of 100 grams of pure cerium is about $380, but in bulk, it is about $1.20 ^[5].

References
1. http://www.rsc.org/periodic-table/element/58/cerium
2. https://education.jlab.org/itselemental/ele058.html
3. https://www.webelements.com/cerium/isotopes.html
4. https://www.livescience.com/37606-cerium.html
5. https://www.chemicool.com/elements/cerium.html
6. http://periodictable.com/Elements/058/data.html
7. http://chemistry-reference.com/q_elements.asp?Symbol=Ce&language=en