Cerium

Cerium
General Info
Atomic Symbol	Atomic symbol::Ce
Atomic Number	Atomic number::58
Atomic Weight	Atomic weight::140.12 g/mol
Chemical series	Lanthanide
Appearance	Cerium Sample
Group, Period, Block	Lanthanide, 6, 4f
Electron configuration	[Xe] 6s24f15d1
Electrons per shell	?, ?
CAS number	CAS number::7440-45-1
Physical properties
Phase	solid
Density	Density::1.93 g/ml
Melting point	Melting point::798°C
Boiling point	Boiling point::3443°C
Isotopes of Cerium
iso NA half-life DT DE (MeV) DP 134Ce syn 3.16 days ε 0.500 134La 136Ce 0.185% 136Ce is stable with 78 neutrons. 138Ce 0.251% 138Ce is stable with 80 neutrons. 139Ce syn 137.640 days ε 0.278 139La 140Ce 88.450% 140Ce is stable with 82 neutrons. 141Ce syn 32.501 days β− 0.581 141Pr 142Ce 11.114% >5x1016 years β−β− 1.417 142Nd 144Ce syn 284.893 days β− 0.319 144Pr
All properties are for STP unless otherwise stated.

Cerium is a chemical element that makes up .00046% of the earths crust and is the most common and abundant of the rare earth metals (lanthanide series). It is also the most reactive and hard to control in it's purest forms (up to 99.9%).

Cerium is a useful metal with many different applications. It's oxide is the most common useful form that it has because of its more docile chemical nature. Cerium resides in the monazite sands and can be harvested by electric currents through cerium chloride. Its ability to ignite is being harnessed and may potentially become a fuel source.

Properties

Cerium is a metal that has a gray/silver color and a slight luster. Cerium is malleable meaning it can be hammered to a thin consistency and is easily shaped. Cerium can oxidize at a fast pace even at room temperature, this process increases when the element is exposed to humid conditions.[1]. This element is considered to be the most abundant of the rare earth metals. It is included in the lanthanide group along with scandium and yttrium. The electrical structure of the elements is unique, it only requires minuscule amount of energy to be able to change to levels at which the electrons are being held. Cerium is a very reactive element it can ignite if it is scratch with a metal instrument. Cerium is considered to be the most reactive of the rare earth metals and because of its almost explosive nature it should be handled with great care. It is a very potent oxidizing agent and is very reactive to hot water as well as cold water. Cerium may react in an explosive manner when zinc is introduced. The elements when found in an impure state may be radioactive due to the high amounts of thorium that it is separated from.[2]

Occurrences

Description

Cerium comes from deposits of Monazite, a mineral made up of three different elements, Cerium, Thorium, and Lanthanum. Thorium is a radioactive element, therefore many deposits of Monazite in which Cerium is found are highly radioactive.[3] Monazite is found mainly on the beaches of Travancore, India, and some of the rivers in Brazil. It will remain obtainable for many years due to the vast deposits in India. The cost of Cerium is around $57 per one hundred grams. It is also found in a few other minerals as well, Cerite, Bastnasite, and Samarskite, but chiefly in Monazite.[4]Pure Cerium is isolated by introducing electric current to cerium chloride.[5]

Uses

Lighter where Cerium is used

Cerium has many different uses. Its tendency to ignite when scratched by sharp objects makes it a necessity for lighting cigarette lighters. It helps to make Misch Metal (a metal flint use in cigarette lighters). Cerium oxide (CeO2) aids the carbon arc lights used to light the stage and studios. Cerium Oxide is used for many different things as well, due to its less reactive state. Unlike pure Cerium, Cerium Oxide has no tendency to ignite when struck. It can be used to polish glass as well as remove its color during production. It may replace jewelers rouge for glass polishing in the near future due to its more effective nature. Cerium Oxide is used in self cleaning ovens and incandescent lantern mantles. The mantle contains cerium oxide which when heated gives off a brighter incandescent glow.[6] Cerium is also used as a catalyst in the production and refinement of the precious petroleum gas. Cerium Oxide is added to the fuel to help reduce the pollution output of engines. It also helps to break down other compounds in petroleum to better the petroleum’s use. Finding ways to make this element more stable in its current form would open news windows as to what we could use it for. Cerium lasers are becoming a new technology that is being put to good use. They produce an ultraviolet light to see carbon dioxide and sulfur dioxide two compounds that pollute our air.

History

Cerium was discovered in 1803 by Jöns Jakob Berzelius and Wilhelm Hisinger. At first cerium was only found in its oxide form and it was named ceria after the asteroid Ceres. The technology that they possessed was not capable of producing its pure form. In its impure form, it contains two other lanthanides, thorium, and lanthanum. Separating the three lanthanides required more technology that any of the scientist had and they also did not discover that it was impure till years later. Mosander discovered that removing these two elements was the key to unlocking pure cerium.[7]

References

• Properties Webelements,1993-2009.
• The Element Cerium Thomas Jefferson National Accelerator Facility - Office of Science Education,2009.
• Indopedia IndoPedia, 2004.
• Chemicool Chemicool, 2009.
• Book Rags
• Cerium by Totally Explained