ChemiPlus Logo
Dictionary - Training


 General | States | Energies | Oxidation & Electrons | Appearance & Characteristics | Reactions | Other Forms Radius | Conductivity | Abundance


Name: Praseodymium Symbol: Pr
Group: Rare Earth, Lanthanides Atomic weight: 140.9077
Density @ 293 K: 6.77 g/cm3 Atomic volume: 20.8 cm3/mol
Group: Rare Earth, Lanthanides discovered: 1885


state (s, l, g): s
melting point: 1204.2 K boiling point: 3293 K
Heat of fusion: 6.890 kJ/mol Heat of vaporization: 296.80 kJ/mol


1st ionization energy: 523.2 kJ/mole
electronegativity: 1.13 2nd ionization energy: 1018 kJ/mole
electron affinity: 50 kJ/mole 3rd ionization energy: 2086 kJ/mole
Specific heat: 0.19 J/gK heat atomization: 356 kJ/mole atoms

Oxidation & Electrons:

Shells: 2,8,18,21,8,2 electron configuration: [Xe] 4f3 6s2
minimum oxidation number: 0 maximum oxidation number: 4
min. common oxidation no.: 0 max. common oxidation no.: 3

Appearance & Characteristics:

structure: cp: close packed (ABCB) color: silvery-white
uses: alloys, Welder's mask toxicity:
hardness: mohs characteristics: soft


reaction with air: vigorous, =>Pr6O11 approx
reaction with 6M HCl: mild, =>H2, PrCl3 reaction with 6M HCl: mild, =>H2, PrCl3
reaction with 15M HNO3: mild, =>Pr(NO3)3 reaction with 6M NaOH:

Other Forms:

number of isotopes: 1 hydride(s): PrH2 PrH3
oxide(s): PrO2 Pr6O11 chloride(s): PrCl3


ionic radius (2- ion): pm ionic radius (1- ion): pm
atomic radius: 182 pm ionic radius (1+ ion): pm
ionic radius (2+ ion): pm ionic radius (3+ ion): 113 pm


thermal conductivity: 12.5 J/m-sec-deg
electrical conductivity: 14.706 1/mohm-cm polarizability: 28.2 A^3


source: Monazite(phosphate),bastnaesite
rel. abund. solar system: -0.778 log abundance earth's crust: 0.9 log
cost, pure: 170 $/100g cost, bulk: $/100g