Elements
61

Pm

Promethium

Promethium (Pm) is a rare metal that has the atomic number 61 in the periodic table. It is a Lanthanide metal. It has the symbol Pm.

Whilst a lot of lanthanides were discovered in the late 1800’s its was not until 1945 that Promethium was produced in the lab from the fission of uranium products. Promethium-147 was isolated by ion exchange chromatography. It was named after the Greek Titan Prometheus who in mythology stole fire from the gods of Mt Olympus. Promethium is the only rare earth metal that is radioactivity. In the dark it will produce a pale blue glow due to its radioactivity. Promethium has uses as a source of beta particles and is used in atomic batteries and missiles. It does not exist in nature and must be produced in the lab. Promethium was the last of the rare earth lanthanides to be discovered. It is a solid metal at room temperature with a melting point of 1042°c and a boiling point of 3000°c.

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FAQ's

What is the Melting Point for Promethium?

Promethium has a Melting Point of 1042°F, meaning at 1042°F it will turn to a liquid.

What is the Boiling Point for Promethium?

Promethium has a Boiling Point of 3000°F, meaning at 3000°F it will turn to a Gas.

What is the Electronegativity of Promethium?

Promethium's Electronegativty is 1.13. Electronegativity is a measure of how strongly atoms attract bonding electrons to themselves.

What is the Heat of Vaporization of Promethium?

Promethium has a Heat of Vaporization of kJ/mol.

Uses

It has been used as a source of radioactivity for thickness-measuring gages.

Sources

Does not occur naturally. Found among fission products of uranium, thorium, and plutonium.

61
Protons
61
Electrons
84
Neutrons

Pm

Element Symbol
Pm
Atomic Weight
145
Atomic Number
61
State
Solid
Melting Point
Unknown
1042
°C
Boiling Point
3000
Unknown
°C
Heat of Vaporization
Unknown
kJ/mol
Crystal Structure
Hexagonal
Thermoconductivity
0.179
Unknown
W/cmK
Shells
2,8,18,23,8,2
Group
Lanthanide
Period
6
Block
F Block
Orbitals
[Xe] 4f5 6s2
Coefficient of Thermal Expansion
--
Covalent Radius
1.63 Å
Density at 293K
6.475 g/cm³
Electrical Conductivity
--
First Ionization Potential
5.55 V
Second Ionization Potential
10.903 V
Third Ionization Potential
22.283 V
Ionic Radius
1.09 (+3) Å
Oxydation States
3
Lattice Parameter
--
Lattice Parameter 2
--
Lattice Parameter 3
5.7828 Å
Pronounced

pro-MEE-thi-em

Discovered by

J.A. Marinsky, L.E. Glendenin, C.D. Coryell

Discovery date

1945

Orbital configuration
2,8,18,23,8,2

Download the Periodic Table

Explore Other Lanthanides

174.967
71

Lu

Lutetium
150.36
62

Sm

Samarium
168.934
69

Tm

Thulium
138.905
57

La

Lanthanum
140.116
58

Ce

Cerium
151.964
63

Eu

Europium
140.908
59

Pr

Praseodymium
173.045
70

Yb

Ytterbium
162.5
66

Dy

Dysprosium
164.93
67

Ho

Holmium
167.259
68

Er

Erbium
158.925
65

Tb

Terbium
144.24
60

Nd

Neodymium
157.25
64

Gd

Gadolinium
The lanthanide series contains 15 metallic elements from number 57 (lanthanum) to 71 (lutetium). They are located in group 3 and in the f-block of period six in the periodic table.
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Neodymium

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