Cerium is a chemical element with an atomic number of 58 in the periodic table of elements. It’s the most abundant rare-earth metal that is found in Earth’s crust. Being a member of the lanthanides family of periodic table elements, this transitional element from period 6 in the periodic table of elements has four valence electrons which assign high reactivity to this chemical element.
Chemical and Physical Properties of Cerium
|Atomic weight (mass)||140.116 g.mol-1|
|Physical state||Solid at 20°C|
|Electronegativity according to Pauling||1.1|
|Density||6.76 g.cm-3 at 20°C|
|Melting point||799°C, 1470°F, 1072 K|
|Boiling point||3443°C, 6229°F, 3716 K|
|Van der Waals radius||0.181 nm|
|Ionic radius||103.4 pm|
|Isotopes||from cerium-119 to cerium-157|
|Most characteristic isotope||140Ce|
|Electronic shell||[Xe] 4f15d16s2|
|The energy of the first ionization||526.8 kJ.mol-1|
|The energy of the second ionization||1045 kJ.mol-1|
|The energy of the third ionization||1945.6 kJ.mol-1|
|Discovery date||In 1803 by Jöns Jacob Berzelius, Wilhelm Hisinger, and Martin Klaproth|
Cerium is a ductile and malleable metal, soft enough to be cut by a sharp object. It’s labeled with the symbol Ce, and has the atomic number 58, atomic mass of 140.116 g.mol -1, and electron configuration [Xe] 4f15d16s2.
Cerium reaches its boiling point at 3443°C, 6229°F, 3716 K, while the melting point is achieved at 799°C, 1470°F, 1072 K. As a result, this metal substance dissolves slowly in cold water, while in hot water it dissolves more quickly.
The second member of the lanthanides family of elements in the periodic table has an electronegativity of 1.1 according to Pauling, whereas the atomic radius according to van der Waals is 0.181 nm. Having +4 and +3 oxidation states that are readily activated at room temperature, this transition metal tarnishes when it comes into contact with oxygen.
In this regard, cerium is a very potent oxidizing agent. Moist air is the most powerful trigger of the oxidation process of cerium. Alkali solutions and all acids also rapidly attack this metal.
How Was Cerium Discovered?
In 1803, the German chemist Martin Heinrich Klaproth (1743 – 1817) managed to distinguish this oxide and describe the new element from ceria (bauxite) ore, but he wasn’t able to isolate it in its elemental form. A bit later that year, two Swedish chemists and avid experimenters, Jöns Jacob Jacob Berzelius (1779 – 1848) and Wilhelm von Hisinger (1766 – 1852), attempted to further analyze the new and rare reddish-brown mineral in Bastnäs, Sweden. With this experiment on the metal oxide called ‘ochra’, they succeeded in both isolating cerium in its pure elemental form, and in assigning its properties as a chemical element.
How Did Cerium Get Its Name?
Berzelius himself labeled the newly discovered element after the asteroid Ceres that was discovered only two years prior to his monumental discovery in the world of chemistry. He made the decision on the name of cerium upon the basis of an astronomical map dating back to the early 17th-century. Ceres was also the Latin name of the Roman Goddess of agriculture and fertility, signifying abundance.
Where Can You Find Cerium?
Lanthanide ores, such as cerite (cerium silicate and cerium salts), monazite, and bastnasite, are the main ores containing cerium. This chemical substance is also obtained by electrolysis of cerium chloride, cerium salts, as well as from the titanium mineral perovskite and the sorosilicate allanite. Traces of cerium can also be found in the fission products of uranium, plutonium, and thorium.
Metallic cerium can be obtained by the processes of electrolysis or thermal reduction that produce the pure metal form of cerium. India, Brazil, and Southern California house the largest cerium deposits in the world.
Cerium in Everyday Life
This rare-earth element is mainly used in industry as an addition to metal alloys composed of iron, steel, or aluminum. Furthermore, it is applied as one of the main components in the following instances:
- Carbon electrodes of arc lamps;
- Cigarette lighters (for the lighter flints);
- As a cadmium replacement for the red pigment in plastic, toys,
- Catalytic converters in exhaust vehicles;
- For incandescent mantles for gas lighting;
- Production of flat-screen televisions;
- Magnetic, optical compact discs;
- Low-energy light bulbs;
- Making of making phosphors (Cerium oxide – Ce2O3 and CeO2);
- Cerium lasers;
- As a catalyst in self-cleaning ovens;
- Manufacturing of glass and ceramics;
- As an abrasive for polishing highly sensitive optical glass, such as telescope mirror or lenses.
A cerium laser is made of a small amount of cerium added to aluminum, lithium, fluorine, and strontium crystals. This type of laser emits light during ultraviolet electromagnetic radiation which is not visible to the human eye. In this way, cerium lasers can detect air pollutants, such as sulfur dioxide and ozone.
How Dangerous Is Cerium?
The cerium used in the items we use every day, such as televisions, abrasives, energy-saving lamps, and glasses, present no significant health hazard. However, cerium becomes a highly toxic substance in the environment where this substance is manufactured or used in the working process.
Upon long-term exposure to cerium, or when inhaled, cerium may cause severe damages to human health, such as lung embolisms or liver problems.
Environmental Effects of Cerium
The heavy metal landfills that collect old household items containing cerium and the petrol-producing industries are some of the biggest cerium contaminators of water, soil, and air. This can lead to an accumulation of high levels of cerium in humans, animals, and plants.
On the brighter side, catalytic cerium converters in exhaust vehicles support the improvement of the air in big cities burdened with heavy traffic. When applied to the catalytic converters of vehicles, cerium traps gas emissions that pollute the atmosphere and burns them off.
Isotopes of Cerium
Cerium-58 is the naturally occurring isotope. It is made up of four stable isotopes: 136Ce, 138Ce, 140Ce, and 142Ce. In addition, 35 radioisotopes (radioactive isotopes) have been differentiated. Among them, the 144Ce isotope is the most stable one, with a half-life of 284.893 days.
|Z||N||Isotopic mass (Da)
[n 2][n 3]
[n 7][n 4]
|Natural abundance (mole fraction)|
|Excitation energy||Normal proportion||Range of variation|
|130mCe||2453.6(3) keV||100(8) ns||(7−)|
|131mCe||61.8(1) keV||5.0(10) min||β+||131La||(1/2+)|
|132mCe||2340.8(5) keV||9.4(3) ms||IT||132Ce||(8−)|
|133mCe||37.1(8) keV||4.9(4) d||β+||133La||9/2−|
|135mCe||445.8(2) keV||20(1) s||IT||135Ce||(11/2−)|
|136Ce||58||78||135.907172(14)||Observationally Stable[n 8]||0+||0.00185(2)||0.00185–0.00186|
|136mCe||3095.5(4) keV||2.2(2) µs||10+|
|137mCe||254.29(5) keV||34.4(3) h||IT (99.22%)||137Ce||11/2−|
|138Ce||58||80||137.905991(11)||Observationally Stable[n 9]||0+||0.00251(2)||0.00251–0.00254|
|138mCe||2129.17(12) keV||8.65(20) ms||IT||138Ce||7-|
|139mCe||754.24(8) keV||56.54(13) s||IT||139Ce||11/2−|
|140mCe||2107.85(3) keV||7.3(15) µs||6+|
|141Ce[n 10]||58||83||140.9082763(26)||32.508(13) d||β−||141Pr||7/2−|
|142Ce[n 10]||58||84||141.909244(3)||Observationally Stable[n 11]||0+||0.11114(51)||0.11114–0.11114|
|143Ce[n 10]||58||85||142.912386(3)||33.039(6) h||β−||143Pr||3/2−|
|144Ce[n 10]||58||86||143.913647(4)||284.91(5) d||β−||144mPr||0+|
|153Ce||58||95||152.94058(43)#||500# ms [>300 ns]||β−||153Pr||3/2−#|
|154Ce||58||96||153.94342(54)#||300# ms [>300 ns]||β−||154Pr||0+|
|155Ce||58||97||154.94804(64)#||200# ms [>300 ns]||β−||155Pr||5/2−#|
List of Cerium Compounds
In compounds, cerium can be both trivalent (Ce3+, cerous) and tetravalent (Ce4+, ceric). Cerium is very reactive with molecules of water. The reaction between Ce and H2O results in cerium(III) hydroxide and hydrogen gas:
2 Ce (s) + 6 H2O (l) → 2 Ce(OH)3 (aq) + 3 H2 (g)
Similarly, trihalides are formed when cerium reacts with any of the halogen elements:
2 Ce (s) + 3 F2 (g) → 2 CeF3 (s) [white]
2 Ce (s) + 3 Cl2 (g) → 2 CeCl3 (s) [white]
2 Ce (s) + 3 Br2 (g) → 2 CeBr3 (s) [white]
2 Ce (s) + 3 I2 (g) → 2 CeI3 (s) [yellow]
The following is a comprehensive list of cerium mineral formations and chemical compounds:
- Cerium acetylacetonate;
- Cerium nitrate;
- Cerium oxalate;
- Cerium(III) bromide;
- Cerium(III) carbonate;
- Cerium(III) chloride;
- Cerium(III) fluoride;
- Cerium(III) hydroxide;
- Cerium(III) iodide;
- Cerium(III) methanesulfonate;
- Cerium(III) oxide;
- Cerium(III) sulfate.
- Ammonium cerium(IV) sulfate;
- Ceric ammonium nitrate;
- Cerium nitrate;
- Cerium uranium blue;
- Cerium(IV) fluoride;
- Cerium(IV) oxide;
- Cerium(IV) sulfate;
- Gadolinium-doped ceria.
5 Interesting Facts and Explanations
- Among the rare-earth elements, only europium is more reactive than cerium.
- The vibrant red color of the everyday plastic items we use comes from cerium.
- Despite being labeled as rare-earth metal, cerium is not so rare. It’s rather the complicated and difficult process conducted to obtain this transition metal that makes it categorized as a rare chemical element.
- An alloy known as mischmetal, made by combining cerium, lanthanum, and other rare-earth metals, is used in the manufacture of cigarette lighter flints.
- More precisely, mischmetal usually contains 50 percent cerium, 25 percent lanthanum, 18 percent neodymium, 5 percent praseodymium, and 2 percent other rare-earth metals.