59
Pr
Praseodymium
140.90766
Praseodymium (Pr)
LanthanidePeriod 6f-block-block
Praseodymium is a chemical element with symbol Pr and atomic number 59. Praseodymium is a soft, silvery, malleable and ductile metal in the lanthanide group. It is valued for its magnetic, electrical, chemical, and optical properties.
Latin name: Praseodymium
Atomic Number
59
Atomic Mass
140.90766 g/mol
Phase (STP)
Solid
Electron Config.
[Xe] 4f³ 6s²
General
SymbolPr
Atomic Number59
Atomic Mass140.90766 g/mol
CategoryLanthanide
Period6
Blockf-block
Electron Configuration[Xe] 4f³ 6s²
Valence Electrons3
Colourgrayish-white metallic
Appearancegrayish white
CAS NumberCAS7440-10-0
Physical Properties
Phase (STP)Solid
Density6.77 g/cm³
Melting Point934.85°C · 1714.73°F · 1208.00 K
Boiling Point3519.85°C · 6367.73°F · 3793.00 K
Atomic Properties
Atomic Radius239 pm
Electronegativity1.13 Pauling
Ionization Energy527 kJ/mol
Oxidation States+3, +4
Ion ChargePr3+/Pr4+
Thermodynamic
Molar Heat27.2 J/(mol·K)
Crystal Structure
Crystal Structurehexagonal close-packed
Mechanical Properties
Mohs Hardness2.5
Nuclear & Hazards
Half-lifestable
Abundance
In Universe0.00005999999999999999%
In Sun0.00005%
In Earth's Crust0.0920%
In Meteorites0.0002%
Discovery & History
Discovery Year1885
Discovered ByCarl Auer von Welsbach
Country of DiscoveryAustria
Isotopes of Praseodymium
| Isotope | Abundance | Half-life | Decay |
|---|---|---|---|
| Pr-141 | 100% | Stable | — |