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7440-10-0

Name PRASEODYMIUM
CAS 7440-10-0
EINECS(EC#) 231-120-3
Molecular Formula Pr
MDL Number MFCD00011174
Molecular Weight 140.91
MOL File 7440-10-0.mol

Chemical Properties

Definition Pr. Metallic element of atomic number 59, group IIIB of the periodic table, one of the rare earth elements of the lanthanide group, aw 140.9077, valences = 3, 4. No stable isotopes.
Appearance metal ingots
Melting point  931 °C (lit.)
Boiling point  3520 °C (lit.)
density  6.71 g/mL at 25 °C(lit.)
storage temp.  Flammables area
form  powder
color  White
Specific Gravity 6.782
Resistivity 68 μΩ-cm, 20°C
Water Solubility  Reacts with water.
Sensitive  Air & Moisture Sensitive
Merck  13,7797
History In 1879, Lecoq de Boisbaudran isolated a new earth, samaria, from didymia obtained from the mineral samarskite. Six years later, in 1885, von Welsbach separated didymia into two others, praseodymia and neodymia, which gave salts of different colors. As with other rare earths, compounds of these elements in solution have distinctive sharp spectral absorption bands or lines, some of which are only a few Angstroms wide. Praseodymium occurs along with other rare-earth elements in a variety of minerals. Monazite and bastnasite are the two principal commercial sources of the rare-earth metals. Ion-exchange and solvent extraction techniques have led to much easier isolation of the rare earths and the cost has dropped greatly. Thirty-seven isotopes and isomers are now recognized. Praseodymium can be prepared by several methods, such as by calcium reduction of the anhydrous chloride or fluoride. Misch metal, used in making cigarette lighters, contains about 5% praseodymium metal. Praseodymium is soft, silvery, malleable, and ductile. It was prepared in relatively pure form in 1931. It is somewhat more resistant to corrosion in air than europium, lanthanum, cerium, or neodymium, but it does develop a green oxide coating that splits off when exposed to air. As with other rare-earth metals it should be kept under a light mineral oil or sealed in plastic. The rare-earth oxides, including Pr2O3, are among the most refractory substances known. Along with other rare earths, it is widely used as a core material for carbon arcs used by the motion picture industry for studio lighting and projection. Salts of praseodymium are used to color glasses and enamels; when mixed with certain other materials, praseodymium produces an intense and unusually clean yellow color in glass. Didymium glass, of which praseodymium is a component, is a colorant for welder’s goggles. The metal (99.9% pure) is priced at about $4/g.
Uses
Praseodymium salts, ingredient of mischmetal, core material for carbon arcs, colorant in glazes and glasses, catalyst, phosphors, lasers.
CAS DataBase Reference 7440-10-0(CAS DataBase Reference)
EPA Substance Registry System Praseodymium (7440-10-0)

Safety Data

Hazard Codes  F
Risk Statements 
R17:Spontaneously flammable in air.
R11:Highly Flammable.
Safety Statements 
S17:Keep away from combustible material .
S7/9:Keep container tightly closed and in a well-ventilated place .
S33:Take precautionary measures against static discharges .
S16:Keep away from sources of ignition-No smoking .
RIDADR  UN 3208 4.3/PG 1
WGK Germany  3
1-10
TSCA  Yes
HazardClass  8
PackingGroup  III
HS Code  28053090

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