Atomic Symbol: Yb
Group: Lanthanide
Atomic number: 70
Atomic Mass: 173.04 amu
Atomic Volume: 24.79 cm3/mol
CAS registry ID: 7440-64-4
Standard State: Solid
Boiling Point: 1466.0 °C (1739.15 °K, 2670.8 °F)
Melting Point: 824.0 °C (1097.15 °K, 1515.2 °F)
Density at 293 K: 6.98 g/cm3
Atomic radius: 193 pm
Electron configuration: [Xe]4f146s2
Electronegativity: Pauling- 1.27 , Allred Rochow- 1.06
First Ionization Energy: 603.4 kJ/mol
Heat of Vaporization: 128.90 kJ/mol
Heat of Fusion: 7.660 kJ/mol
Specific Heat: 0.15 J/gK
Heat Atomization: 152 kJ/mol atoms
Thermal Conductivity: 34.9 J/m-sec-deg
Electrical Conductivity: 35.7 1/mohm-cm
Polarizability: 21 A^3
Oxidation State: +2, +3
Shells: 2,8,18,32,8,2
Discovery:
In 1843 Swedish chemist C. G. Mosander isolated three rare earth materials from the mineral gadolinite: yttria, erbia and terbia. In 1878, Swiss chemist Jean Charles Galissard de Marignac discovered that erbia was not one element, but two separate components. One retained the name erbia, while the other was renamed ytterbia by Marignac. He believed that ytterbia was a compound of a new element, ytterbium.
While attempting to discover the properties of ytterbium through testing, scientists came up with varying results. Some attributed the strange results to faulty testing procedure or equipment, but French chemist G. Urbain believed this was caused by ytterbium being two separate elements. In 1907 he isolated the two elements: neoytterbia (new ytterbium) and lutecia. Eventually, the names were changed to ytterbium and lutetium.
Properties:
This element has a bright silvery luster, and is malleable and quite ductile. Though it is stable, it should be kept in closed containers to protect it from air and moisture. It is easily dissolved with both diluted and strong mineral acids, and reacts slowly with water. It has a low acute toxic rating. The natural form is a mixture of seven stable isotopes.
Production and Uses:
Ytterbium occurs in rare minerals (xenotime, monazite, and bastnaesite being the most useful) with other rare earth elements. It is primarily obtained from monazite sand ((Ce, La, Th, Nd, Y)PO4) which contains about 0.03% ytterbium. To separate it from other rare earth elements ion-exchange and solvent extraction techniques are used. A pure form of the element is obtainable through the electrolysis of a mixture of molten YbCl3 and NaCl (or CaCl2) in a graphite cell which acts as cathode using graphite as anode (with chlorine gas as a byproduct).
Ytterbium has one radioactive isotope which is used as a radiation source in portable X-Ray machines where electricity is not available. It is used in superconductors. It can also be alloyed with stainless steel to improve some of its mechanical properties (such as grain refinement and strength).
Ytterbium of ninety-nine percent-plus purity costs about $875/kg.
Sources:
http://www.chemicool.com/elements/ytterbium.html
http://education.jlab.org/itselemental/ele070.html
http://pearl1.lanl.gov/periodic/elements/70.html