promethium

• Description
• General information
• Physical data
• Radii
• Electronegativities
• Solid state structure
• Temperatures
• Enthalpies
• Ionization Enthalpies
• Isotopes
• Further information

Description

Great care is required while handling promethium as a consequence of its radioactivity. Promethium salts luminesce in the dark with a pale blue or greenish glow, due to their high radioactivity. Ion-exchange methods led to the preparation of about 10 g of promethium from atomic reactor fuel processing wastes in early 1963.

Little is yet generally known about the properties of metallic promethium. More than 30 promethium compounds have been prepared. Promethium is a rare earth metal. It appears that there is no known Pm existing in the earth's crust.

General information

Discoveror: J. A. Marinsky, Lawrence Glendenin, Charles D. Coryell
Date discovered: 1945
Discovered at: United States
Meaning of name: Named after "Prometheus" in Greek mythology, who stole fire from the gods

Physical data

Standard state: solid at 298 K
Colour: metallic
Density of solid at ambient temperature/kg m^-3: 7264
Molar volume/cm³: 20.23

Radii /pm

Atomic: 205
Covalent (single bond):
Pauling radius for the ion [Pm]^-: no data

Valence shell orbital radius maxima (R_max)

orbital	s	p	d	f
radius	219.0	no data	no data	33.3

Electronegativities

Both values are quoted on the Pauling scale.

Pauling: no data
Allred Rochow: 1.07

Crystal Structure

structure:

The following CrystalMaker image represents the solid state structure. For most elements, the most stable allotrope is illustrated. Try WebElements version 2 for interactive virtual reality and CHIME images.

Temperatures (/K)

melting point: 1373
boiling point: 3273

Enthalpies /kJ mol^-1

fusion: 7.13
vaporization: 289

single bond enthalpies:

Pm-F	Pm-Cl	Pm-Br	Pm-I	Pm-Pm
no data	no data	no data	305	no data

Ionization enthalpies /kJ mol^-1

Number	Enthalpy
1st	536
2nd	1052
3rd	2150
4th	3970
5th	5950

Isotopes

This section gives some data for naturally occurring isotopes.

Nominal mass	Accurate mass	% natural abundance
		nil

Further Information

• Additional information about WebElements 1.2.2
• This is a licensed copy (here is the full list) of WebElements 1.2.2 and contains a subset of the material contained within the main version of WebElements (version 2)
• For further information please try WebElements version 2
• Sheffield Chemdex: perhaps the largest internet chemistry directory
• Sheffield Chemputer: interactive chemistry calculators on the WWW