lithium

= Thulium = Jonathan Leal

ELEMENT NAME: **Thulium** ELEMENT SYMBOL: **Tm** ATMOIC NUMBER: **69** ATOMIC MASS: **168.93421** NUMBER OF PROTONS: **69** NUMBER OF ELECTRONS: **69** NUMBER OF NEUTRONS: **1**

__**Configuration:**__ ELECTRON CONFIGURATION: [Xe ] 4f13 6s2 ISOTOPES: 1


 * __Physical properties__:** Pure thulium metal has a bright, silvery luster. It is reasonably stable in air, but should be protected from moisture. The metal is soft, malleable, and ductile.
 * melting point: 818 K (1545°C or 2813°F)
 * boiling point: 2223 K (1950°C or 3542°F)
 * density: 9.32 grams per cubic centimeter

__**Chemical Properties:**__ Thulium metal tarnishes slowly in air and burns readily at 150°C to form : -Thulium is quite electropositive and reacts slowly with cold water and thulium oxidequite quickly with hot water to form thulium hydroxide:-Thulium reacts with all the halogens at temperatures. Reactions are slow at room temperature, but are vigorous above 200 °C: -Thulium dissolves readily in dilute sulfuric acid to form solutions containing the pale green Tm(III) ions, which exist as a [Tm(OH2)9]3+ complexes:[3] -Thulium reacts with various metallic and non-metallic elements forming a range of binary compounds, including TmN, TmS, TmC2, Tm2C3, TmH2, TmH3, TmSi2, TmGe3, TmB4, TmB6 and TmB12. In those compounds, thulium exhibits valence states +2, +3 and +4, however, the +3 state is most common and only this state has been observed in Tm solutions.

Thulium was discovered by Per Theodor Cleve, a Swedish chemist, in 1879. Cleve used the same method Carl Gustaf Mosander used to discover lanthanum, erbium and terbium, he looked for impurities in the oxides of other rare earth elements. He started with erbia, the oxide of erbium (Er2O3), and removed all of the known contaminants. After further processing, he obtained two new materials, one brown and the other green. Cleve named the brown material holmia and the green material thulia. Holmia is the oxide of the element holmium and thulia is the oxide of the element thulium. Today, thulium is primarily obtained through an ion exchange process from monazite sand ((Ce, La, Th, Nd, Y)PO4), a material rich in rare earth elements that can contain as much as 0.007% thulium.
 * History:**

radiation source for portable X-ray machines.
 * __Medical Use:__** Thulium is the least abundant of the naturally occurring rare earth elements. Metallic thulium is relatively expensive and has only recently become available. It currently has no commercial applications, although one of its isotopes, thulium-169, could be used as a

Number of stable Isotopes: 1 Data: http://education.jlab.org/itselemental/iso069.html



http://www.espi-metals.com/metals/catthulium.htm http://education.jlab.org/itselemental/ele069.html http://en.wikipedia.org/wiki/Thulium
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