Ytterbium
Ytterbium is a chemical element with symbol Yb and atomic number 70. It is the fourteenth and penultimate element in the lanthanide series, which is the basis of the relative stability of its +2 oxidation state. However, like the other lanthanides, its most common oxidation state is +3, seen in its oxide, halides and other compounds.
Identity
- Atomic mass
- 173.045 u
- Category
- Lanthanides
- Group
- 3
- Period
- 6
- Block
- f
- Oxidation States
- +2, +3
- Phase (25 °C)
- Solid
Electronic Structure
- Electron configuration
- 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p6 6s2 4f14
- Short configuration
- [Xe] 4f14 6s2
- Electrons per shell
- 2, 8, 18, 32, 8, 2
- Electronegativity (Pauling)
- 1.10
- Electron affinity
- -1.93 kJ/mol
- 1st ionization energy
- 603 kJ/mol
- Ionization energies
- 603 · 1175 · 2417 · 4203 kJ/mol
Physical properties
- Melting point
- 823.9 °C (1097 K)
- Boiling point
- 1195.8 °C (1469 K)
- Density
- 6.9 g/cm³
- Molar heat capacity
- 26.7 J/(mol·K)
Chemical behavior of ytterbium
Ytterbium has fourteen outer electrons ([Xe] 4f¹⁴ 6s²) and acts as +3, with a very stable +2 due to its full 4f shell. Its electronegativity is very low (1.10) and it is the most volatile and softest lanthanide. It oxidizes slowly in air and reacts with water. Its Yb³⁺ ions generate the most efficient 1-micron fiber laser in the industry.
Reactivity
4 Yb + 3 O₂ → 2 Yb₂O₃
In air it tarnishes slowly with a white oxide; in moist air the corrosion progresses. When heated, it burns to the oxide.
2 Yb + 6 H₂O → 2 Yb(OH)₃ + 3 H₂
It reacts with water more vigorously than most lanthanides, releasing hydrogen. The doped fibers are insoluble and stable.
2 Yb + 6 HCl → 2 YbCl₃ + 3 H₂
It dissolves in acids giving colorless ytterbium(III) salts. The chloride is the raw material for laser fibers and optical clocks.
2 YbCl₃ + Zn → 2 YbCl₂ + ZnCl₂
With reducing agents it goes to ytterbium(II), which precipitates and allows it to be separated: the same purification trick as with europium.
Notable compounds
| Compound | Formula | Use or importance |
|---|---|---|
| Ytterbium oxide | Yb₂O₃ | Laser fibers and ceramics |
| Ytterbium-doped fiber | SiO₂:Yb | Industrial cutting and welding |
| Ytterbium(II) iodide | YbI₂ | Reducing agent in organic synthesis |
| Ytterbium chloride | YbCl₃ | Lasers and atomic clocks |
| Sealed ytterbium-169 | ¹⁶⁹Yb | Portable industrial radiography |
Electron shell distribution
View in the atom builderIsotopes
Natural ytterbium mixes seven stable isotopes: 168Yb (~0.13%), 170Yb (~3%), 171Yb (~14.3%), 172Yb (~21.8%), 173Yb (~16.1%), 174Yb (~31.8%) and 176Yb (~12.8%), all with 70 protons. 171Yb powers optical clocks and quantum bits; 176Yb is a target for producing medical lutetium-177.
Occurrence and production
It appears at about 3 ppm in monazite, bastnasite and xenotime alongside erbium and lutetium. The main deposits are in China, the United States and Australia. It is obtained by acid dissolution, solvent extraction and reduction of the +2 state, and the metal by electrolysis or reduction with lanthanum.
History and origin of the name
Jean Charles Galissard de Marignac separated it in 1878 from erbium and named it ytterbium, after Ytterby, the Swedish village of the rare earths. Urbain and Auer later split it into ytterbium and lutetium. For a century it was a curiosity until laser fibers and optical clocks made it strategic.
Applications and relevance of ytterbium
Uses of the element
As a dopant in fibers it generates kilowatt lasers that cut cars and weld batteries with 30% efficiency. As a trapped atom in optical lattices it marks the second in the world's most precise clocks.
Uses of its compounds
The oxide dopes laser ceramics and 1-micron amplifiers; sealed Yb-169 radiographs welds without electricity. Trapped Yb-171 ions are qubits of quantum computing.
Health, safety and environment
Biological role
It has no biological function and its toxicity is low. Fibers and ceramics are insoluble and do not release ytterbium; clocks use isolated atoms without contact with people.
Safety
Fine powder can ignite in air and requires extraction and an inert atmosphere. Yb-169 sources travel shielded with dosimetry; fiber lasers require enclosures and IR glasses.
Environment
Its production is low but its footprint per kilo is high because of the fine separation. In return, every fiber laser replaces dirtier thermal and chemical processes. Fiber and target recycling recovers ytterbium.
Frequently asked questions about Ytterbium
Why is ytterbium used in the most precise atomic clocks?
Ytterbium-171 can be trapped in optical lattices formed by lasers, where its electronic transitions are extraordinarily stable. By measuring those oscillations, ytterbium atomic clocks reach a precision far superior to that of traditional clocks. This accuracy is relevant for satellite navigation, telecommunications, geodesy and fundamental physics experiments, where small variations in time can have measurable consequences.
Is ytterbium dangerous?
Ytterbium has low toxicity and no essential biological function is known in the body. However, the metal can react with air and moisture, and fine powder can be flammable. Soluble compounds or compounds in the form of nanoparticles can irritate skin, eyes or the respiratory tract. For this reason, its industrial handling requires ventilation, personal protection and storage in closed containers, preferably under an inert atmosphere.
Where does ytterbium come from?
Ytterbium is found in rare-earth minerals such as monazite, bastnasite and xenotime, mixed with other lanthanides. After chemical treatment of the ore, it is separated by solvent extraction and ion exchange. It can then be obtained as an oxide, salt or metal. Its global production is relatively low, but its demand grows because of fiber lasers, optical clocks and precision technologies.
What role can ytterbium play in quantum computing?
Ytterbium-171 ions can be trapped and manipulated with lasers to work as qubits, the basic units of quantum information. Their energy levels are stable and their transitions can be controlled with precision, which makes them attractive for quantum computing based on trapped ions. This line of research seeks to build processors capable of solving certain problems much faster than classical computers.
What is ytterbium used for in industrial lasers?
Ytterbium is used as a dopant in fibers and crystals of high-power lasers. These systems generate very concentrated and efficient beams that are used to cut, weld, mark and engrave metals in the automotive, aerospace, electronics and industrial manufacturing sectors. Ytterbium-doped fiber lasers stand out for their good beam quality, their energy efficiency and their reliability in intensive duty cycles.
What is ytterbium-169 used for in industrial radiography?
Ytterbium-169 emits gamma rays and can be used as a portable radiographic source to inspect metal parts. Placed in front of a film or detector, it reveals internal defects in foundries, welds and pipes without damaging the object. It is a non-destructive testing technique useful for quality control in industries where structural reliability is critical.
What is the difference between ytterbium and erbium in optical fiber?
Erbium amplifies signals in the band close to 1,550 nanometers, the most used in long-distance telecommunications. Ytterbium, by contrast, is used above all in high-power amplifiers and lasers, with wavelengths close to 1 micrometer. Therefore erbium dominates conventional fiber networks and the Internet, while ytterbium stands out in industrial cutting, welding, laser marking and high-power scientific applications.
Main sources consulted: PubChem, Royal Society of Chemistry, NIST, IUPAC. Last revision: November 2026.