Promethium

61
Pm
Group
n/a
Period
6
Block
f
Protons
Electrons
Neutrons
61
61
84
General Properties
Atomic Number
61
Atomic Weight
[145]
Mass Number
145
Category
Lanthanides
Colour
Silver
Radioactive
Yes
Named after the Greek Prometheus, who, according to mythology, stole fire from heaven
Crystal Structure
n/a
History
The existence of an element between neodymium and samarium was first predicted by Czech chemist Bohuslav Brauner in 1902.

Promethium was first produced and characterized at Oak Ridge National Laboratory in 1945 by Jacob A. Marinsky, Lawrence E. Glendenin and Charles D. Coryell.

It was produced by the separation and analysis of the fission products of uranium fuel irradiated in a graphite reactor.
Electrons per shell
2, 8, 18, 23, 8, 2
Electron Configuration
[Xe] 4f5 6s2
Pm
Promethium is the only lanthanide that has no stable isotopes
Physical Properties
Phase
Solid
Density
7.26 g/cm3
Melting Point
1315.15 K | 1042 °C | 1907.6 °F
Boiling Point
3273.15 K | 3000 °C | 5432 °F
Heat of Fusion
7.7 kJ/mol
Heat of Vaporization
290 kJ/mol
Specific Heat Capacity
-
Abundance in Earth's crust
n/a
Abundance in Universe
n/a
Pitchblende,
Image Credits: Wikimedia Commons (Geomartin)
Pitchblende, a uranium ore and the host for most of Earth's promethium
CAS Number
7440-12-2
PubChem CID Number
n/a
Atomic Properties
Atomic Radius
183 pm
Covalent Radius
199 pm
Electronegativity
-
Ionization Potential
5.582 eV
Atomic Volume
22.39 cm3/mol
Thermal Conductivity
0.179 W/cm·K
Oxidation States
3
Applications
Promethium is also used in atomic batteries for spacecraft and guided missiles.

Promethium is also used to measure the thickness of materials by evaluating the amount of radiation from a promethium source that passes through the sample.

It has possible future uses in portable X-ray sources, and as auxiliary heat or power sources for space probes and satellites.
Promethium is harmful due to its radioactivity
Isotopes
Stable Isotopes
-
Unstable Isotopes
126Pm, 127Pm, 128Pm, 129Pm, 130Pm, 131Pm, 132Pm, 133Pm, 134Pm, 135Pm, 136Pm, 137Pm, 138Pm, 139Pm, 140Pm, 141Pm, 142Pm, 143Pm, 144Pm, 145Pm, 146Pm, 147Pm, 148Pm, 149Pm, 150Pm, 151Pm, 152Pm, 153Pm, 154Pm, 155Pm, 156Pm, 157Pm, 158Pm, 159Pm, 160Pm, 161Pm, 162Pm, 163Pm