dys·pro·si·um /dɪsˈproziəm, ʒ(i)əm/
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dys·pro·si·um /dɪsˈprozɪəm, ʒ(ɪ)əm/ 名詞
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Dys·pro·si·um n. Chem. An element of the rare earth-group. Symbol Dy; at. wt., 162.5.
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dysprosium
n : a trivalent metallic element of the rare earth group; forms
compounds that are highly magnetic [syn: Dy, atomic
number 66]
dysprosium
Symbol: Dy
Atomic number: 66
Atomic weight: 162.50
Metallic with a bright silvery-white lustre. Dysprosium belongs to the
lanthanoids. It is relatively stable in air at room temperatures, it will
however dissolve in mineral acids, evolving hydrogen. It is found in
from rare-earth minerals. There are seven natural isotopes of dysprosium,
and eight radioisotopes, Dy-154 being the most stable with a half-life of
3*10^6 years. Dysprosium is used as a neutron absorber in nuclear fission
reactions, and in compact disks. It was discovered by Paul Emile Lecoq de
Boisbaudran in 1886 in France. Its name comes from the Greek word
dysprositos, which means hard to obtain.