Lutetium
LANTHANOID · GROUP None · PERIOD 6
71
Lu
Lutetium
174.97
Atomic Data
| Atomic Number | 71 |
| Symbol | Lu |
| Atomic Weight | 174.97 u |
| Density (STP) | 9.841 g/cm³ |
| Melting Point | 1651.85 °C (1925 K) |
| Boiling Point | 3401.85 °C (3675 K) |
| Electronegativity | 1.27 (Pauling) |
| Electron Config. | 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 4f14 5s2 5p6 5d1 6s2 |
| Oxidation States | +3 |
| Phase at STP | Solid |
| Category | Lanthanoid |
| Period / Group | 6 / None |
| CAS Number | 7439-94-3 |
Electron Configuration
{{BOHR_SVG}}
[Xe] 4f14 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 | 14 | 60 |
| O | 5 | 5s | 2 | 62 |
| O | 5 | 5p | 6 | 68 |
| O | 5 | 5d | 1 | 69 |
| P | 6 | 6s | 2 | 71 |
| Total | 71 | 71 | ||
Isotopes of Lutetium
Lutetium has two naturally occurring stable isotopes. The most abundant is ¹⁷⁵Lu, comprising 97.401% of all naturally occurring Lutetium.
| Isotope | Symbol | Protons | Neutrons | Abundance | Stability |
|---|---|---|---|---|---|
| Lutetium-175 | ¹⁷⁵Lu | 71 | 104 | 97.401 | Stable |
| Lutetium-176 | ¹⁷⁶Lu | 71 | 105 | 2.599 | Stable |
Abundance & Occurrence
Lutetium is present in Earth's crust at approximately 0.8 ppm by mass and at approximately 0.01 ppm by mass throughout the universe.
Earth's Crust (ppm by mass)
Lutetium
0.8 ppm
Silicon (ref.)
277,000 ppm
Oxygen (ref.)
461,000 ppm
Universe (ppm by mass)
Lutetium
0.01 ppm
Helium (ref.)
230,000 ppm
Hydrogen (ref.)
739,000 ppm
Discovery & History
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Safety & Handling
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Lutetium 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.