iron

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

Description

Iron is a relatively abundant element in the universe. It is found in the sun and many types of stars in considerable quantity. Iron nuclei are very stable. Iron is a vital constituent of plant and animal life, and is the key component of haemoglobin.

The pure metal is not often encountered in commerce, but is usually alloyed with carbon or other metals. The pure metal is very reactive chemically, and rapidly corrodes, especially in moist air or at elevated temperatures. Any car owner knows this. Iron metal is a silvery, lustrous metal which has important magnetic properties.

General information

Discoveror: Known since ancient times
Date discovered:
Discovered at: not known
Meaning of name: From the Anglo-Saxon word "iron" (the origin of the symbol Fe comes from the Latin word "ferrum") meaning "iron"

Physical data

Standard state: solid at 298 K
Colour: lustrous, metallic, greyish tinge
Density of solid at ambient temperature/kg m^-3: 7874
Molar volume/cm³: 7.09

Radii /pm

Atomic: 156
Covalent (single bond):
Pauling radius for the ion [Fe]^-: no data

Valence shell orbital radius maxima (R_max)

orbital	s	p	d	f
radius	136.6	no data	38.2	no data

Electronegativities

Both values are quoted on the Pauling scale.

Pauling: 1.83
Allred Rochow: 1.64

Crystal Structure

structure: bcc (body-centred cubic)

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: 1811
boiling point: 3134

Enthalpies /kJ mol^-1

fusion: 13.8
vaporization: 345

single bond enthalpies:

Fe-F	Fe-Cl	Fe-Br	Fe-I	Fe-Fe
no data	no data	no data	339.7	100

Ionization enthalpies /kJ mol^-1

Number	Enthalpy
1st	759.4
2nd	1561
3rd	2957.4
4th	5290
5th	7240
6th	9600
7th	12100
8th	14575

Isotopes

This section gives some data for naturally occurring isotopes.

Nominal mass	Accurate mass	% natural abundance
54Fe	53.9396127 (15)	5.8 (1)
56Fe	55.9349393 (16)	91.72 (30)
57Fe	56.9353958 (16)	2.2 (1)
58Fe	57.9332773 (16)	0.28 (1)

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