Science Fair Project Encyclopedia
|Name, Symbol, Number||Dysprosium, Dy, 66|
|Group, Period, Block||_ , 6, f|
|Density, Hardness||8551 kg/m3, no data|
|Appearance|| silvery white|
|Atomic weight||162.500(1) amu|
|Atomic radius (calc.)||175 (228) pm|
|Covalent radius||no data|
|van der Waals radius||no data|
|e- 's per energy level||2, 8, 18, 28, 8, 2|
|Oxidation states (Oxide)||3 (weak base)|
|State of matter||solid (ferromagnetic)|
|Melting point||1680 K (2565 °F)|
|Boiling point||2840 K (4653 °F)|
|Molar volume||19.01 ×10-6 m3/mol|
|Heat of vaporization||230 kJ/mol|
|Heat of fusion||11.06 kJ/mol|
|Vapor pressure||no data|
|Velocity of sound||2170 m/s at 293.15 K|
|Electronegativity||1.22 (Pauling scale)|
|Specific heat capacity||170 J/(kg*K)|
|Electrical conductivity||1.08 106/m ohm|
|Thermal conductivity||10.7 W/(m*K)|
|1st ionization potential||573.0 kJ/mol|
|2nd ionization potential||1130 kJ/mol|
|3rd ionization potential||2200 kJ/mol|
|4th ionization potential||3990 kJ/mol|
|Most stable isotopes|
|SI units & STP are used except where noted.|
Dysprosium is a rare earth element that has a metallic, bright silver luster, relatively stable in air at room temperature, but dissolving readily in dilute or concentrated mineral acids with the emission of hydrogen. It is soft enough to be cut with a knife, and can be machined without sparking if overheating is avoided. Dysprosium's characteristics can be greatly affected even by small amounts of impurities.
Dysprosium is used, in conjunction with vanadium and other elements, for making laser materials; its high thermal neutron absorption cross-section and melting point also suggest using it for nuclear control rods, dysprosium oxide (also known as dysprosia) with nickel cement compounds which absorb neutrons readily without swelling or contracting under prolonged neutron bombardment, is being used for cooling rods in nuclear reactors. Dysprosium-cadmium chalcogenides are sources of infrared radiation for studying chemical reactions; furthermore, dysprosium is used for manufacturing compact discs.
Dysprosium was first identified in Paris in 1886 by French chemist Paul Émile Lecoq de Boisbaudran; however, the element itself was not isolated in relatively pure form until after the development of ion exchange and metallographic reduction techniques in the 1950s. The name dysprosium is derived from Greek dysprositos, "hard to get at".
Dysprosium is never encountered as the free element, but is found in many minerals, including xenotime, fergusonite , gadolinite, euxenite, polycrase , blomstrandine , monazite and bastnasite, often with erbium and holmium or other rare earth elements.
Nearly all dysprosium compounds are in the +3 oxidation state, and are highly paramagnetic. Dysprosium compounds include:
Naturally occurring dysprosium is composed of 7 stable isotopes, 156-Dy, 158-Dy, 160-Dy, 161-Dy, 162-Dy, 163-Dy and 164-Dy, with 164-Dy being the most abundant (28.18% natural abundance). 28 radioisotopes have been characterized, with the most stable being 154-Dy with a half-life of 3.0E+6 years, 159-Dy with a half-life of 144.4 days, and 166-Dy with a half-life of 81.6 hours. All of the remaining radioactive isotopes have half-lifes that are less than 10 hours, and the majority of these have half lifes that are less than 30 seconds. This element also has 5 meta states, with the most stable being 165m-Dy (t˝ 1.257 minutes), 147m-Dy (t˝ 55.7 seconds) and 145m-Dy (t˝ 13.6 seconds).
The primary decay mode before the most abundant stable isotope, 164-Dy, is electron capture, and the primary mode after is beta minus decay. The primary decay products before 164-Dy are terbium isotopes, and the primary products after are holmium isotopes.
As with the other lanthanides, dysprosium compounds are of low to moderate toxicity, although their toxicity has not been investigated in detail. Dysprosium does not have any known biological properties.
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