Cerium
LANTHANOID · GROUP None · PERIOD 6
58
Ce
Cerium
140.12
Atomic Data
| Atomic Number | 58 |
| Symbol | Ce |
| Atomic Weight | 140.12 u |
| Density (STP) | 6.77 g/cm³ |
| Melting Point | 794.85 °C (1068 K) |
| Boiling Point | 3442.85 °C (3716 K) |
| Electronegativity | 1.12 (Pauling) |
| Electron Config. | 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 4f1 5s2 5p6 5d1 6s2 |
| Oxidation States | +3, +4 |
| Phase at STP | Solid |
| Category | Lanthanoid |
| Period / Group | 6 / None |
| CAS Number | 7440-45-1 |
Electron Configuration
{{BOHR_SVG}}
[Xe] 4f1 5d1 6s2
| Shell | n | Subshell | Electrons | Cumulative |
|---|---|---|---|---|
| K | 1 | 1s | 2 | 2 |
| L | 2 | 2s | 2 | 4 |
| L | 2 | 2p | 6 | 10 |
| M | 3 | 3s | 2 | 12 |
| M | 3 | 3p | 6 | 18 |
| M | 3 | 3d | 10 | 28 |
| N | 4 | 4s | 2 | 30 |
| N | 4 | 4p | 6 | 36 |
| N | 4 | 4d | 10 | 46 |
| N | 4 | 4f | 1 | 47 |
| O | 5 | 5s | 2 | 49 |
| O | 5 | 5p | 6 | 55 |
| O | 5 | 5d | 1 | 56 |
| P | 6 | 6s | 2 | 58 |
| Total | 58 | 58 | ||
Isotopes of Cerium
Cerium has four naturally occurring stable isotopes. The most abundant is ¹⁴⁰Ce, comprising 88.45% of all naturally occurring Cerium.
| Isotope | Symbol | Protons | Neutrons | Abundance | Stability |
|---|---|---|---|---|---|
| Cerium-136 | ¹³⁶Ce | 58 | 78 | 0.185 | Stable |
| Cerium-138 | ¹³⁸Ce | 58 | 80 | 0.251 | Stable |
| Cerium-140 | ¹⁴⁰Ce | 58 | 82 | 88.45 | Stable |
| Cerium-142 | ¹⁴²Ce | 58 | 84 | 11.114 | Stable |
Abundance & Occurrence
Cerium is present in Earth's crust at approximately 66 ppm by mass and at approximately 1 ppm by mass throughout the universe.
Earth's Crust (ppm by mass)
Cerium
66 ppm
Silicon (ref.)
277,000 ppm
Oxygen (ref.)
461,000 ppm
Universe (ppm by mass)
Cerium
1 ppm
Helium (ref.)
230,000 ppm
Hydrogen (ref.)
739,000 ppm
Discovery & History
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Safety & Handling
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Cerium in the Real World
Real-World Uses
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Downloadable Resources
Free periodic table reference sheets for classrooms, study sessions, and laboratory use.