Cerium metal

详情

Description:
 
Cerium Metal is silver lump. It is used as additive for special steel, Non-ferric Alloy, Hydrogen Storage Alloy, also reducer for making other Rare Earth metal.

Cerium is a chemical element with symbol Ce and atomic number *8. It is a soft, silvery, ductile metal which easily oxidizes in air. Cerium was named after the dwarf planet Ceres (itself named for the Roman goddess of agriculture). Cerium is the most abundant of the rare earth elements, making up about 0.***6% of the Earth's crust by weight. It is found in a number of minerals, the most important being monazite and bastnasite. Commercial applications of cerium are numerous. They include catalysts, additives to fuel to reduce emissions and to glass and enamels to change their color. Cerium oxide is an important component of glass polishing powders and phosphors used in screens and fluorescent lamps. It is also used in the "flint" (actually ferrocerium) of lighters.
 
Physical properties:
 
Cerium is a silvery metal, belonging to the lanthanide group. It resembles iron in color and luster, but is soft, and both malleable and ductile. Cerium has the third-longest liquid range of any element: ***8 C° (**5 °C to ***3 °C) or ***6 F° (***3 °F to ***9 °F). (Only neptunium and thorium have longer liquid ranges.)
 
Chemical properties:
 
Cerium metal tarnishes slowly in air and burns readily at **0 °C to form cerium(IV) oxide:
 
    Ce + O2→CeO2
 
Cerium is quite electropositive and reacts slowly with cold water and quite quickly with hot water to form cerium hydroxide:
 
    2 Ce (s) + 6 H2O (l)→2 Ce(OH)3 (aq) + 3 H2 (g)
 
Cerium metal reacts with all the halogens:
 
    2 Ce (s) + 3 F2 (g)→2 CeF3 (s) [white]
    2 Ce (s) + 3 Cl2 (g)→2 CeCl3 (s) [white]
    2 Ce (s) + 3 Br2 (g)→2 CeBr3 (s) [white]
    2 Ce (s) + 3 I2 (g)→2 CeI3 (s) [yellow]
 
Cerium dissolves readily in dilute sulfuric acid to form solutions containing the colorless Ce(III) ions, which exist as a [Ce(OH2)9]3+ complexes:[8]
 
    2 Ce (s) + 3 H2SO4 (aq)→2 Ce3+ (aq) + 3 SO2−
    4 (aq) + 3 H2 (g)