Pr

Praseodymium

Identification

CAS Number: 7440-10-0

Discovery Year: 1885

Discoverer: C.F. Aver von Welsbach

Discovery Location: Austria

Properties

Atomic Mass: 140.90766 →Density: 6.773 g/cm³ →

Crust Abundance: 9.2 mg/kg

Crystal Structure: HEX

Atomic Dimensions

Atomic Radius: 185 pm →

Atomic Radius (Rahm): 286 pm

Covalent Radius: 202.99999999999997 pm →

Van der Waals Radius: 240 pm

Atomic Volume: 20.8 cm³/mol

Lattice Constant: 3.67 Å

Thermodynamics

Melting Point: 1204 K →Boiling Point: 3785 K →Specific Heat: 0.192 J/(g·K) →Thermal Conductivity: 12.5 W/(m·K) →Heat of Fusion: 11.3 kJ/mol →Heat of Vaporization: 331 kJ/mol →

Heat of Formation: 356.9 kJ/mol

Electronic Structure

Electron Config: [Xe] 4f3 6s2

Block: f

Period: 6 →Electronegativity: 1.13 →Electron Affinity: 0.9620000000000001 eV →

Oxidation States: +3, +4

Abundance & Geochemistry

Crust Abundance: 9.2 mg/kg

Sea Abundance: 6.4e-7 mg/L

Geochemical Class: rare earth & related

Goldschmidt Class: litophile

About

Soft silvery metallic element, belongs to the lanthanoids. Only natural isotope is Pr-141 which is not radioactive. Fourteen radioactive isotopes have been artificially produced. Used in rare-earth alloys. Discovered in 1885 by C.A. von Welsbach.

Isotopes

Pr-141 141 100.00%