58CeCerium140.1161[Xe] 4f¹ 5d¹ 6s²
lanthanide

Cerium

Cerium is a chemical element with symbol Ce and atomic number 58. It is a soft, silvery, ductile metal which easily oxidizes in air. Cerium was named after the dwarf planet Ceres (itself named after the Roman goddess of agriculture).

Properties

At a glance

Atomic number
58
Atomic mass
140.1161 u
Phase
Solid
Density
6.77 g/cm³
Melting point
1,068 K
Boiling point
3,716 K
First ionization energy
534.4 kJ/mol
Electronegativity
1.12
Electron affinity
55 kJ/mol
Molar heat capacity
26.94 J/(mol·K)
Period
6
Appearance
silvery white

Conditions and isotopes affect measured properties. Some properties of short-lived elements are predicted. Electronegativity uses the Pauling scale.

Electronic structure

Cerium’s orbitals use a hydrogen-like approximation. Every orbital of each visible subshell is shown: in Shapes as the surface holding half its probability, with light and dark shades for opposite signs of the wavefunction; in Cloud as dots where its electrons are likely to be. Sizes are stepped by shell, like the Shell model.

Electrons by shell
Electron configuration

54 is the [Xe] core total across five shells.

Preparing the orbital view…

58 protons82 neutrons

Cerium-140: its most common form in nature, or its longest-lived if it has none. The nucleus is drawn far too big: it’s about 100,000 times smaller than the atom.

States of matter

Turn up the heat

298 KK stands for kelvin, the temperature scale used in science. It starts at absolute zero (0 K), the coldest temperature possible, so it has no negative numbers and no degree sign.

A step of 1 K is the same size as 1 °C, so the two scales are always 273.15 apart. Fahrenheit is different: its degrees are smaller and it starts elsewhere, so water freezes at 273.15 K, 0 °C and 32 °F.25 °C · 77 °FSolid

At this temperature, cerium is a solid.

At normal atmospheric pressure (1 atm). The temperature scale is logarithmic. The particle box is schematic: real samples hold vastly more atoms, and spacing and speeds are not to scale.

Ionization energy

Pull the electrons off

Ce

CeNeutral atom · no charge

A neutral cerium atom. Removing its first electron takes 534 kJ/mol.

Cerium’s outer shell holds 2 electrons. Electron 3 is the first from an inner shell: it sits closer to the nucleus with less shielding, so removing it takes 1.8× as much energy as the one before. Each dashed line on the chart marks another jump, into a shell even closer to the nucleus.

Shell 1Shell 2Shell 3Shell 4Shell 5Shell 6MeasuredEstimated or calculatedEnergy in kJ/molkJ/mol (kilojoules per mole) is the energy to remove that electron from every atom in a mole of them: about 602 sextillion (6.02 × 10²³) atoms. For a single atom, divide by 96.485 to get electronvolts (eV). Cerium’s first electron takes about 5.5 eV.
1001,00010,000100,0001,000,00010,000,000Shell 5Shell 4Shell 3Shell 2×1.8×1.1×1.7×2.3×4.11510152025303540455055
Show the values as a table
ElectronShellEnergy (kJ/mol)× previousValue
16534–Measured
261,0572Estimated
351,9491.8Estimated
453,5611.8Estimated
556,3251.8Estimated
657,4871.2Estimated
758,7801.2Calculated
8510,2271.2Calculated
9512,0611.2Calculated
10513,5081.1Calculated
11516,5951.2Calculated
12418,5481.1Estimated
13430,1031.6Calculated
14432,8051.1Calculated
15435,7961.1Calculated
16438,8841.1Calculated
17441,9711.1Calculated
18445,5411.1Calculated
19449,1111.1Calculated
20452,3921.1Calculated
21455,8651.1Calculated
22459,1461.1Calculated
23472,2681.2Calculated
24475,7411Calculated
25479,5041Calculated
26483,1701Calculated
27489,1521.1Calculated
28493,1081Calculated
294102,2741.1Calculated
304106,4721Estimated
313184,0941.7Calculated
323192,3921Calculated
333201,3651Calculated
343210,8201Calculated
353219,9871Calculated
363229,4421Calculated
373241,2131.1Calculated
383250,8621Calculated
393261,0891Calculated
403270,7381Calculated
413297,8501.1Calculated
423306,4371Calculated
433315,8931Calculated
443324,7701Calculated
453344,4531.1Calculated
463354,2941Calculated
473372,9161.1Calculated
483382,3711Calculated
492870,2982.3Calculated
502894,3231Calculated
512920,9521Calculated
522945,8461Calculated
5321,017,1481.1Calculated
5421,045,9011Calculated
5521,081,6011Calculated
5621,105,7071Calculated
5714,519,4034.1Calculated
5814,628,0051Calculated

Successive ionization energies of gas-phase atoms and ions from the NIST Atomic Spectra Database. Solid bars are measured; hatched bars were estimated from nearby measurements or calculated from quantum theory, as is usual for highly charged ions. Electrons are taken from the outermost shell first, a simplification: electrons in different subshells of the same shell also differ in energy. On the log scale each gridline is 10 times the one below.

Compared with other elements

How does it compare?

CeriumOther lanthanidesOther elements

Density

6.77 g/cm³47th lowest of 99

Ce

Melting point

1,068 K41st lowest of 96

Ce

Boiling point

3,716 K20th highest of 97

Ce

Electronegativity

1.1215th lowest of 96

Ce

First ionization energy

534 kJ/mol13th lowest of 99

Ce

Elements 1–99 from the reference data; heavier elements are left out because only a few atoms have ever been made, so their bulk properties are predictions. First ionization energies come from NIST. Density uses a logarithmic scale, because gases are around a thousand times less dense than solids; gas densities are at 0 °C and 1 atm. Melting and boiling points are at normal pressure. Everyday temperatures and light sources in the pictures are approximate. Hover over a dot to see the element, or click it to compare.

Keep exploring

Explore the stories, imagery, and reference data in more depth. Properties with no value in the reference are marked unavailable.