Element Praseodymium

Praseodymium ElementAn element of the rare earth family of metals. It has the atomic symbol Pr, atomic number 59, and atomic weight 140.91.
Praseodymium atom is a lanthanoid atom and a f-block element atom.
It is the third member of the lanthanide series and is traditionally considered to be one of the rare-earth metals. Praseodymium is a soft, silvery, malleable and ductile metal, valued for its magnetic, electrical, chemical, and optical properties. It is too reactive to be found in native form, and pure praseodymium metal slowly develops a green oxide coating when exposed to air.

Names and Identifiers

Chemical Formula:Pr
CAS:7440-10-0
Molecular Weight:140.908g/mol
EC Number :231-120-3
MDL Number:MFCD00011174
Color:silvery white, yellowish tinge
Other Names:Praseodym, Praséodyme
PubChem CID:23942
IUPAC Name:Praseodymium
Inchl:InChI=1S/Pr
InChI Key:PUDIUYLPXJFUGB-UHFFFAOYSA-N
Canonical SMILES:[Pr]
ICSC Number:n/a

Physical & Chemical Properties

Phase:Solid
Density:6.77g/cm³
Boiling Point:3403 K ​(3130 °C, ​5666 °F)
Melting Point:1208 K ​(935 °C, ​1715 °F)
Molecular Formula:Pr
Flash Point:n/a
Exact Mass:140.907593
Symbol:Globally Harmonized System of Classification
Signal Word:Danger
Hazard Statements:H250
Precautionary Statements:P222-P231-P422
Hazard Codes:F: Flammable;
Risk Phrases:R17
Safety Phrases:17-7/9-33-16
RIDADR:UN 3208 4
WGK Germany:3
RTECS:n/a
Packaging Group:III
Hazard Class:n/a

Praseodymium has only one stable and naturally occurring isotope, 141Pr.
It is thus a mononuclidic element, and its standard atomic weight can be determined with high precision as it is a constant of nature

Naturally occurring isotopes

IsotopeMass/DaNatural abundance (atom %)Nuclear spin (I)Magnetic moment (μ/μN)
141Pr140.907647 (4)1005/24.136

Radiosotope data

IsotopeMass/DaHalf-lifeMode of decayNuclear spinNuclear magnetic moment
137Pr136.910681.28 hEC to 137Ce5/2
138Pr137.910751.45 mEC to 138Ce1
139Pr138.908934.41 hEC to 139Ce5/2
140Pr139.909073.39 mEC to 140Ce1
142Pr141.91004119.12 hEC to 142Ce; β to 142Nd20.234
143Pr142.91081313.57 dβ to 143Nd7/22.7
144Pr143.91330117.28 mβ to 144Nd0
145Pr144.914515.98 hβ to 145Nd7/2

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