Ytterbium (Yb)

Stable isotopes of ytterbium available from ISOFLEX

Isotope Z(p) N(n) Atomic Mass Natural Abundance Enrichment Level Chemical Form
Yb-168  70  98  167.933895 0.13%  35.00-87.00% Oxide
Yb-170  70  100  169.934758 3.05% >70.00% Oxide
Yb-171 70 101 170.936323 14.30% 95.00-97.50% Oxide
Yb-172 70 102 171.936378 21.90% >98.00% Oxide
Yb-173 70 103 172.938207 16.12% >92.00% Oxide
Yb-174 70 104 173.938858 31.80% >99.00% Oxide
Yb-176 70 106 175.942569 12.70% >99.60% Oxide

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Ytterbium was discovered in 1878 by Jean de Marignac. It is named after the village of Ytterby, near Vaxholm, Sweden.

Ytterbium is a silvery, lustrous metal that is soft, malleable and ductile. The metal exists in two allotropic forms: an alpha form, which has a face-centered cubic structure and a density of 6.98 g/cm3 and is stable at room temperature; and a beta form, with a body-centered cubic modification and a density of 6.54 g/cm3.The beta form appears when the alpha form is heated to 798 ºC. Ytterbium reacts slowly with water and is soluble in dilute acids and liquid ammonia. It reacts with oxygen above 200 ºC. It forms two oxides: a monoxide and a more stable sesquioxide. The metal dissolves in dilute and concentrated mineral acids. Similar to other rare earth metals, ytterbium is corroded slowly at ordinary temperatures by caustic alkalis, ammonium hydroxide and sodium nitrate solutions. The metal also dissolves in liquid ammonia, forming a deep blue solution. Reactions with halogens are slow at room temperature but progress rapidly above 200 ºC, forming ytterbium trihalides. At elevated temperatures, ytterbium forms many binary, metalloid and intermetallic compounds with a number of elements.

Ytterbium metal has very little commercial use. In elemental form it is a laser source, a portable x-ray source, and a dopant in garnets. When added to stainless steel, it improves grain refinement, strength and other properties. Some other applications include carbon rods for industrial lighting, titanate-insulated capacitors, and additives to glass. The radioactive isotope Ytterbium-169 is used in portable devices to examine defects in thin steel and aluminum. The metal and its compounds are used in fundamental research.

Properties of Ytterbium

Name Ytterbium 
Symbol Yb 
Atomic number 70 
Atomic weight 173.04 
Standard state Solid at 298 ºK 
CAS Registry ID 7440-64-4
Group in periodic table N/A 
Group name Lanthanoid 
Period in periodic table 6 (Lanthanoid) 
Block in periodic table f-block 
Color Silvery white 
Classification Metallic 
Melting point 824 °C
Boiling point 1194 °C
Vaporization point 1194 °C
Thermal conductivity 34.9 W/(m·K)
Electrical resistivity 25.0 µΩ·cm at 25 ºC 
Electronegativity 1.1 
Specific heat 0.3 kJ/kg K 
Heat of vaporization 160 kJ·mol-1
Heat of fusion 7.7 kJ·mol-1
Density of liquid 6.21 g/cm3 at 824 °C
Density of solid 6.97 g/cm3
Electron configuration [Xe]4f146s2 
Atomic radius 1.945 Å
Ionic radius Yb3+: 0.868 Å (coordination number 6) and
0.98 Å (coordination number 8)
Oxidation states  +2, +3 

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