Ytterbium Facts – Symbol Yb or Atomic Number 70

Ytterbium is a soft, silvery-white metallic element that belongs to the lanthanide series of the periodic table. It has the symbol Yb and the atomic number 70. Like other rare earth elements, ytterbium is not especially rare, despite the name. It has interesting optical, magnetic, and nuclear properties that make it valuable in various advanced technologies, including lasers, atomic clocks, and materials testing.

Key Ytterbium Facts

• Symbol: Yb
• Atomic number: 70
• Element group: Lanthanides (rare earth metals)
• Standard state: Solid at room temperature
• Named after: The village of Ytterby, Sweden, like yttrium, terbium, and erbium

History of Discovery, Isolation, and Naming

Ytterbium’s discovery story ties in with the other rare earths, as these elements occur together in ores:

• 1878 – Swiss chemist Jean Charles Galissard de Marignac discovered a new component in the mineral gadolinite and named the substance ytterbia, believing it to be a new oxide of a unique element.
• 1907 – French chemist Georges Urbain separated ytterbia into two different substances: one retained the name ytterbium (oxide: Yb₂O₃), and the other was named lutetia (oxide: Lu₂O₃), leading to the identification of two new elements: ytterbium and lutetium.
• 1907 – Independently, Carl Auer von Welsbach also performed a similar separation and proposed different names (aldebaranium and cassiopeium), but Urbain’s names were officially adopted.
• Isolation – Pure ytterbium metal was first isolated in 1937 by Klemm and Bonner through reduction with potassium.

Periodic Table Location and Element Group

• Block: f-block (inner transition metals)
• Group: Lanthanides (no formal group number)
• Period: 6

Ytterbium is a lanthanide and often grouped with rare earth elements. It is the twelfth element in the lanthanide series, between thulium and lutetium and directly above nobelium.

Appearance and Allotropes

• Color: Silvery-white with a metallic luster
• Texture: Soft and malleable
• Allotropes: Ytterbium has three allotropes:
  • α-Ytterbium (face-centered cubic) at room temperature and pressure
  • β-Ytterbium (body-centered cubic) at higher temperatures and pressure
  • γ-Ytterbium (hexagonal close-packed) at high pressure

These allotropes differ in atomic packing and influence the element’s electrical properties. The beta allotrope is an electrical conductor under ordinary conditions, but becomes a semiconductor at higher pressure. The allotropes have different magnetic properties from one another. The alpha allotrope is diamagnetic, while the other forms are paramagnetic.

Characteristics and Properties

• Softest lanthanide after europium
• Smallest liquid temperature range of any metal
• Fairly reactive, especially in air and moisture
• Tarnishes slowly in air, forming a yellow or golden oxide layer
• Reacts with water to form hydrogen gas
• Paramagnetic at room temperature but exhibits superconductivity under certain conditions

Ytterbium’s electrical resistance is sensitive to pressure, making it valuable for high-precision materials testing.

Isotopes of Ytterbium

Ytterbium has 7 naturally occurring isotopes, which are all stable: Yb-168, Yb-170, Yb-171, Yb-172, Yb-173, Yb-174, and Yb-176. Ytterbiun-174 is the most abundant isotope, accounting for 31.8% of the natural abundance.

In addition to these stable isotopes, more than 30 radioisotopes have been synthesized, most of which have very short half-lives.

Origin, Abundance, and Sources

• Origin: Ytterbium forms via the s-process and r-process in stellar nucleosynthesis.
• Abundance in Earth’s crust: ~3.2 mg/kg
• Abundance in seawater: ~0.0002 µg/L

Ytterbium is more abundant than its neighbors on the periodic table, following the Oddo-Harkins rule for an even-numbered element.

Natural Sources:

• Monazite (a phosphate mineral rich in rare earths)
• Xenotime (a phosphate of yttrium group elements)
• Bastnäsite

Major mining operations are in China, the United States, Brazil, Sri Lanka, India, and Australia.

Extraction:

• Ytterbium is extracted through ion-exchange and solvent extraction from monazite sand.
• Purified via reduction of its anhydrous halides with calcium or lithium.

Uses of Ytterbium

Ytterbium has a variety of high-tech and industrial applications:

Optics and Lasers:

• Ytterbium-doped fiber lasers (Yb:YAG): efficient and powerful solid-state lasers
• Medical lasers: surgical and dermatological procedures

Timekeeping and Standards:

• Ytterbium atomic clocks: among the most precise timekeeping devices, used in research and GPS calibration

Materials Testing:

• Acts as a stress gauge due to sensitivity of electrical resistance to pressure

Nuclear Technology:

• Yb-169 is a gamma-ray source in radiography

Metallurgy:

• Improves grain refinement, strength, and other mechanical properties in stainless steel and other alloys

Emerging Uses:

• Ion qubits for quantum computing
• Thermoelectric materials

Oxidation States

Ytterbium commonly exhibits the +2 and +3 oxidation states:

• Yb(III): Most stable and common
• Yb(II): Found in some compounds like ytterbium(II) iodide (YbI₂); this state is pale yellow and more reducing

The 0 and +1 states also occur, although they are rare.

Chemistry and Compounds

Ytterbium behaves like other lanthanides:

• Forms trivalent salts: YbCl₃, Yb(NO₃)₃, Yb₂O₃
• Divalent salts (Yb²⁺) are more reducing and typically pale yellow
• Reacts with:
  • Oxygen: forms ytterbium oxide (Yb₂O₃)
  • Water: forms ytterbium hydroxide
  • Acids: forms corresponding ytterbium salts, releasing H₂

Biological Role, Health Effects, and Toxicity

Biological Role:

• No known essential biological function
• Found in trace amounts in soil, plants, and animals

Health Effects:

• Low toxicity, similar to other lanthanides
• Exposure may occur through inhalation or ingestion of dust or fumes

Toxicity in Organisms:

• Soluble ytterbium salts may pose some risks to aquatic organisms
• Insoluble compounds tend to be inert

Ytterbium compounds are generally considered safe for research and industrial use when proper handling protocols are followed.

Ytterbium Facts Table (For Scientists)

Comparing Ytterbium With Other Lanthanides

While ytterbium shares many general properties with other lanthanides—such as forming predominantly +3 oxidation state compounds, being trivalent metals, and having similar ionic radii—it also exhibits several distinctive physical, chemical, and nuclear characteristics that set it apart.

1. Oxidation States

• Ytterbium commonly forms both +3 and +2 oxidation states, whereas most lanthanides predominantly exhibit only the +3 state.
• The +2 state is more stable in ytterbium than in most other lanthanides, similar to europium and samarium, due to a half-filled (Eu²⁺) or filled (Yb²⁺) 4f subshell.

2. Electron Configuration

• Ytterbium has the electron configuration [Xe] 4f¹⁴ 6s², meaning its 4f subshell is completely filled.
• This closed-shell configuration makes ytterbium less chemically reactive and contributes to its soft texture and low melting point compared to other lanthanides.

3. Physical Properties

Ytterbium is one of the softest and least dense of the lanthanides, second only to lanthanum in low density.

4. Magnetism and Superconductivity

• Most lanthanides are strongly paramagnetic, owing to unpaired 4f electrons.
• Ytterbium, with a filled 4f shell, is only weakly paramagnetic and can become diamagnetic in certain compounds.
• Some ytterbium compounds exhibit superconductivity at low temperatures, a rare feature among lanthanide-based materials.

5. Optical and Laser Applications

• Ytterbium is widely used in high-power laser systems, especially in Yb:YAG lasers, due to:
  • High energy efficiency
  • Long energy-level lifetimes
  • Minimal thermal lensing
• It has narrow linewidth transitions, useful for high-resolution atomic clocks and quantum optics, applications not typical of most lanthanides.

6. Pressure Sensitivity

• The electrical resistivity of ytterbium is uniquely sensitive to pressure.
• This property is used in stress gauges—a niche use among lanthanides, which are not typically sensitive to external pressure.

Summary

Ytterbium stands out among the lanthanides due to its:

• Stable +2 oxidation state
• Completely filled 4f shell
• Unusually soft and low-density metallic form
• Weak magnetic behavior
• Superconductivity in some compounds
• Laser and atomic timekeeping applications
• High pressure-sensitive resistivity

These properties make ytterbium valuable in cutting-edge technologies that go beyond the more traditional uses of other rare earths like neodymium, cerium, or lanthanum.

Interesting Ytterbium Facts

• Ytterbium is one of four elements named after Ytterby, Sweden—a record unmatched by any other location.
• An ytterbium-based atomic clock only gains or loses a single second over the age of the universe.
• Despite being part of the rare earths, ytterbium is more abundant than tin in Earth’s crust.
• Ytterbium metal is soft enough to cut with a knife.
• Yb lasers are more efficient than Nd:YAG lasers and are used in high-power cutting and welding tools.
• Some ytterbium compounds glow under ultraviolet light, making them useful in luminescent materials and tags.
• It plays a role in experimental quantum simulation setups in atomic physics labs.

References

• Emsley, John (2003). Nature’s Building Blocks: An A-Z Guide to the Elements. Oxford University Press. ISBN 978-0-19-850340-8.
• Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. ISBN 978-0-08-037941-8.
• Kouznetsov, D.; Bisson, J.-F.; Takaichi, K.; Ueda, K. (2005). “Single-mode solid-state laser with short wide unstable cavity”. Journal of the Optical Society of America B. 22 (8): 1605–1619. doi:10.1364/JOSAB.22.001605
• Olmschenk, S. (2007). “Manipulation and detection of a trapped Yb171+ hyperfine qubit”. Physical Review A. 76 (5): 052314. doi:10.1103/PhysRevA.76.052314
• Weeks, Mary Elvira (1932). “The discovery of the elements. XVI. The rare earth elements”. Journal of Chemical Education. 9 (10): 1751. doi:10.1021/ed009p1751