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The samarium is a rare metal on Earth. It is silver in color, relatively stable
in the open air and ignites spontaneously at 150 กใ C. Three modifications of the
metal structure exist in particular at 734 กใ C and 922 กใ C.
The natural samarium is composed of five stable isotopes (144Sm, 149Sm, 150Sm,
152Sm and 154Sm) and two very long half-life radioisotopes, 147Sm (1.06 กม 1011
a) and 148Sm (7 กม 1015 a), 152Sm being the most abundant (22.75%). 146Sm also
has a very long half-life (1.03 กม 108 a), but it is naturally present only in
trace amounts, as a product of explosive nucleosynthesis8.
Permanent magnets: in alloy with cobalt: SmCo5 and Sm2Co17. The SmCo5 magnets
have the highest known demagnetization resistance. [Ref. desired]
Neutron sensor: the samarium has a very high capacity for capturing thermal
neutrons. Its isotopes are common fission products in nuclear reactors,
particularly the isotope 149 which is a neutron poison, the samarium 149
accumulates in the heart creating a loss of reactivity which is called poisoning
samarium whose mechanism is close to xenon poisoning.
Electronics: ceramic capacitors use a dielectric based on lanthanum, neodymium
or samarium oxides.
Optics: added to glass, its Sm2O3 oxide allows strong absorption of infrared.
Medicine: 153samarium is used in symptomatic radiotherapy, mainly to relieve
pain due to bone metastases.
It is found in the microphones of electric guitars as in the control rods of
certain nuclear reactors.
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rhenium germanium zirconium cadmium hafnium
barium lithium beryllium strontium calcium
Tantalum gadolinium samarium yttrium ytterbium
Lutetium praseodymium holmium erbium thulium dysprosium
terbium europium lanthanum cerium neodymium scandium
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