francium

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

Description

Francium occurs as a result of a disintegration of actinium. Francium is found in uranium minerals, and can be made artificially by bombarding thorium with protons. It is the most unstable of the first 101 elements. The longest lived isotope, ²²³Fr, a daughter of ²²⁷Ac, has a half-life of 22 minutes. This is the only isotope of francium occurring in nature, but at most there is only 20-30 g of the element present in the earth's crust at any one time. No weighable quantity of the element has been prepared or isolated. There are 20 known isotopes.

General information

Discoveror: Marguerite Perey
Date discovered: 1939
Discovered at: France
Meaning of name: Named after "France"

Physical data

Standard state: solid at 298 K
Colour: metallic
Density of solid at ambient temperature/kg m^-3: no data
Molar volume/cm³: no data

Radii /pm

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

Valence shell orbital radius maxima (R_max)

orbital	s	p	d	f
radius	298.6	no data	no data	no data

Electronegativities

Both values are quoted on the Pauling scale.

Pauling: 0.7
Allred Rochow: 0.86

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: no data
boiling point: 273

Enthalpies /kJ mol^-1

fusion: 2.1
vaporization: 64

single bond enthalpies:

Fr-F	Fr-Cl	Fr-Br	Fr-I	Fr-Fr
no data	no data	no data	no data	no data

Ionization enthalpies /kJ mol^-1

Number	Enthalpy
1st	400

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