Cerium (Ce)

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 number58
Atomic weight (mass)140.116 g.mol-1
Group numberLanthanides
ColorIron-gray metal
Physical stateSolid at 20°C
Half-life32.501 days
Electronegativity according to Pauling1.1
Density6.76 g.cm-3 at 20°C
Melting point799°C, 1470°F, 1072 K
Boiling point3443°C, 6229°F, 3716 K
Van der Waals radius0.181 nm
Ionic radius103.4 pm
Isotopesfrom cerium-119 to cerium-157
Most characteristic isotope140Ce
Electronic shell[Xe] 4f15d16s2
The energy of the first ionization526.8 kJ.mol-1
The energy of the second ionization1045 kJ.mol-1
The energy of the third ionization1945.6 kJ.mol-1
Discovery dateIn 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.

Cerium Lasers

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. 



[n 1]

ZNIsotopic mass (Da)


[n 2][n 3]



[n 4]




[n 5]




[n 6]

Spin and



[n 7][n 4]

Natural abundance (mole fraction)
Excitation energyNormal proportionRange of variation
119Ce5861118.95276(64)#200# msβ+119La5/2+#  
120Ce5862119.94664(75)#250# msβ+120La0+  
121Ce5863120.94342(54)#1.1(1) sβ+121La(5/2)(+#)  
122Ce5864121.93791(43)#2# sβ+122La0+  
β+, p121Ba
123Ce5865122.93540(32)#3.8(2) sβ+123La(5/2)(+#)  
β+, p122Ba
124Ce5866123.93041(32)#9.1(12) sβ+124La0+  
125Ce5867124.92844(21)#9.3(3) sβ+125La(7/2−)  
β+, p124Ba
126Ce5868125.92397(3)51.0(3) sβ+126La0+  
127Ce5869126.92273(6)29(2) sβ+127La5/2+#  
128Ce5870127.91891(3)3.93(2) minβ+128La0+  
129Ce5871128.91810(3)3.5(3) minβ+129La(5/2+)  
130Ce5872129.91474(3)22.9(5) minβ+130La0+  
130mCe2453.6(3) keV100(8) ns  (7−)  
131Ce5873130.91442(4)10.2(3) minβ+131La(7/2+)  
131mCe61.8(1) keV5.0(10) minβ+131La(1/2+)  
132Ce5874131.911460(22)3.51(11) hβ+132La0+  
132mCe2340.8(5) keV9.4(3) msIT132Ce(8−)  
133Ce5875132.911515(18)97(4) minβ+133La1/2+  
133mCe37.1(8) keV4.9(4) dβ+133La9/2−  
134Ce5876133.908925(22)3.16(4) dEC134La0+  
135Ce5877134.909151(12)17.7(3) hβ+135La1/2(+)  
135mCe445.8(2) keV20(1) sIT135Ce(11/2−)  
136Ce5878135.907172(14)Observationally Stable[n 8]0+0.00185(2)0.00185–0.00186
136mCe3095.5(4) keV2.2(2) µs  10+  
137Ce5879136.907806(14)9.0(3) hβ+137La3/2+  
137mCe254.29(5) keV34.4(3) hIT (99.22%)137Ce11/2−  
β+ (.779%)137La
138Ce5880137.905991(11)Observationally Stable[n 9]0+0.00251(2)0.00251–0.00254
138mCe2129.17(12) keV8.65(20) msIT138Ce7-  
139Ce5881138.906653(8)137.641(20) dEC139La3/2+  
139mCe754.24(8) keV56.54(13) sIT139Ce11/2−  
140Ce[n 10]5882139.9054387(26)Stable0+0.88450(51)0.88446–0.88449
140mCe2107.85(3) keV7.3(15) µs  6+  
141Ce[n 10]5883140.9082763(26)32.508(13) dβ141Pr7/2−  
142Ce[n 10]5884141.909244(3)Observationally Stable[n 11]0+0.11114(51)0.11114–0.11114
143Ce[n 10]5885142.912386(3)33.039(6) hβ143Pr3/2−  
144Ce[n 10]5886143.913647(4)284.91(5) dβ144mPr0+  
145Ce5887144.91723(4)3.01(6) minβ145Pr(3/2−)  
146Ce5888145.91876(7)13.52(13) minβ146Pr0+  
147Ce5889146.92267(3)56.4(10) sβ147Pr(5/2−)  
148Ce5890147.92443(3)56(1) sβ148Pr0+  
149Ce5891148.9284(1)5.3(2) sβ149Pr(3/2−)#  
150Ce5892149.93041(5)4.0(6) sβ150Pr0+  
151Ce5893150.93398(11)1.02(6) sβ151Pr3/2−#  
152Ce5894151.93654(21)#1.4(2) sβ152Pr0+  
153Ce5895152.94058(43)#500# ms [>300 ns]β153Pr3/2−#  
154Ce5896153.94342(54)#300# ms [>300 ns]β154Pr0+  
155Ce5897154.94804(64)#200# ms [>300 ns]β155Pr5/2−#  
156Ce5898155.95126(64)#150# msβ156Pr0+  
157Ce5899156.95634(75)#50# msβ157Pr7/2+#  

Source: Wikipedia

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 minerals:

  • Abenakiite-(Ce)
  • Anzaite-(Ce)
  • Cerianite-(Ce)
  • Dyrnaesite-(La)
  • Monazite-(Ce)
  • Tancaite-(Ce)
  • Zirsilite-(Ce)

Cerium(III) 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.

Cerium(IV) compounds:

  • 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

  1. Among the rare-earth elements, only europium is more reactive than cerium. 
  2. The vibrant red color of the everyday plastic items we use comes from cerium. 
  3. 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.   
  4. An alloy known as mischmetal, made by combining cerium, lanthanum, and other rare-earth metals, is used in the manufacture of cigarette lighter flints.
  5. More precisely, mischmetal usually contains 50 percent cerium, 25 percent lanthanum, 18 percent neodymium, 5 percent praseodymium, and 2 percent other rare-earth metals.