Praseodymium

59
Pr
Group
n/a
Period
6
Block
f
Protons
Electrons
Neutrons
59
59
82
General Properties
Atomic Number
59
Atomic Weight
140.90765
Mass Number
141
Category
Lanthanides
Colour
Silver
Radioactive
No
From the Greek word prasios, green, and didymos, twin
Crystal Structure
Simple Hexagonal
History
Praseodymium was first identified in 1885, in Vienna, by the Austrian chemist Carl Auer von Welsbach.

It was discovered in didymium, a substance incorrectly said by Carl Gustav Mosander to be a new element in 1841.

Pure metallic praseodymium was first produced in 1931.
Electrons per shell
2, 8, 18, 21, 8, 2
Electron Configuration
[Xe] 4f3 6s2
Pr
Praseodymium is usually stored under a light mineral oil or sealed in glass
Physical Properties
Phase
Solid
Density
6.773 g/cm3
Melting Point
1208.15 K | 935 °C | 1715 °F
Boiling Point
3793.15 K | 3520 °C | 6368 °F
Heat of Fusion
6.9 kJ/mol
Heat of Vaporization
330 kJ/mol
Specific Heat Capacity
0.193 J/g·K
Abundance in Earth's crust
0.00086%
Abundance in Universe
2×10-7%
Ultrapure
Image Credits: Images-of-elements
Ultrapure praseodymium pieces under argon
CAS Number
7440-10-0
PubChem CID Number
23942
Atomic Properties
Atomic Radius
182 pm
Covalent Radius
203 pm
Electronegativity
1.13 (Pauling scale)
Ionization Potential
5.473 eV
Atomic Volume
20.8 cm3/mol
Thermal Conductivity
0.125 W/cm·K
Oxidation States
2, 3, 4
Applications
Praseodymium is used as an alloying agent with magnesium to create high-strength metals that are used in aircraft engines.

Misch metal, used in making cigarette lighters, contains about 5% praseodymium metal.

Praseodymium is used to make specialized yellow glass goggles for glass blowers and welders.
Praseodymium is considered to be moderately toxic
Isotopes
Stable Isotopes
141Pr
Unstable Isotopes
121Pr, 122Pr, 123Pr, 124Pr, 125Pr, 126Pr, 127Pr, 128Pr, 129Pr, 130Pr, 131Pr, 132Pr, 133Pr, 134Pr, 135Pr, 136Pr, 137Pr, 138Pr, 139Pr, 140Pr, 142Pr, 143Pr, 144Pr, 145Pr, 146Pr, 147Pr, 148Pr, 149Pr, 150Pr, 151Pr, 152Pr, 153Pr, 154Pr, 155Pr, 156Pr, 157Pr, 158Pr, 159Pr