Fe - Iron

Iron's main use is in making steel. When steel is combined with chromium, it produces stainless steel, which is resistant to corrosion

The table below shows the abundance of Iron in Universe, Sun, Meteorites, Earth's Crust, Oceans and Human Body.

The solid state structure of Iron is Body Centered Cubic.

The Crystal structure can be described in terms of its unit Cell. The unit Cells repeats itself in three dimensional space to form the structure.

Unit Cell Parameters

The unit cell is represented in terms of its lattice parameters, which are the lengths of the cell edges Lattice Constants (a, b and c)

and the angles between them Lattice Angles (alpha, beta and gamma).

The positions of the atoms inside the unit cell are described by the set of atomic positions ( x_i, y_i, z_i) measured from a reference lattice point.

The symmetry properties of the crystal are described by the concept of space groups. All possible symmetric arrangements of particles in three-dimensional space are described by the 230 space groups (219 distinct types, or 230 if chiral copies are considered distinct.

Space Group Name	Im_ 3m
Space Group Number	229
Crystal Structure	Body Centered Cubic
Number of atoms per unit cell	2

Iron atoms have 26 electrons and the electronic shell structure is [2, 8, 14, 2] with Atomic Term Symbol (Quantum Numbers) ⁵D₄.

Atomic Number	26
Number of Electrons (with no charge)	26
Number of Protons	26
Mass Number	56
Number of Neutrons	30
Shell structure (Electrons per energy level)	2, 8, 14, 2
Electron Configuration	[Ar] 3d6 4s2
Valence Electrons	3d6 4s2
Valence (Valency)	3
Main Oxidation States	2, 3
Oxidation States	-4, -2, -1, 0, 1, 2, 3, 4, 5, 6, 7
Atomic Term Symbol (Quantum Numbers)	5D4

Bohr Atomic Model of Iron - Electrons per energy level

n		s	p	d	f

Ground State Electronic Configuration of Iron - neutral Iron atom

Abbreviated electronic configuration of Iron

The ground state abbreviated electronic configuration of Neutral Iron atom is [Ar] 3d6 4s2. The portion of Iron configuration that is equivalent to the noble gas of the preceding period, is abbreviated as [Ar]. For atoms with many electrons, this notation can become lengthy and so an abbreviated notation is used. This is important as it is the Valence electrons 3d6 4s2, electrons in the outermost shell that determine the chemical properties of the element.

Unabbreviated electronic configuration of neutral Iron

Complete ground state electronic configuration for the Iron atom, Unabbreviated electronic configuration

1s2 2s2 2p6 3s2 3p6 3d6 4s2

Electrons are filled in atomic orbitals as per the order determined by the Aufbau principle, Pauli Exclusion Principle and Hund’s Rule.

As per the Aufbau principle the electrons will occupy the orbitals having lower energies before occupying higher energy orbitals. According to this principle, electrons are filled in the following order: 1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, 5s, 4d, 5p, 6s, 4f, 5d, 6p, 7s, 5f, 6d, 7p…

The Pauli exclusion principle states that a maximum of two electrons, each having opposite spins, can fit in an orbital.

Hund's rule states that every orbital in a given subshell is singly occupied by electrons before a second electron is filled in an orbital.

Atomic Structure of Iron

Iron atomic radius is 156 pm, while it's covalent radius is 125 pm.

Spectral Lines of Iron - Atomic Spectrum of Iron

A spectral line is a dark or bright line in an otherwise uniform and continuous spectrum, resulting from an excess or deficiency of photons in a narrow frequency range, compared with the nearby frequencies. Spectral lines are often used to identify atoms and molecules.

Spectral lines are the result of interaction between a quantum system and a single photon. A spectral line may be observed either as an emission line or an absorption line.

Spectral lines are highly atom-specific, and can be used to identify the chemical composition of any medium. Several elements, including helium, thallium, and caesium, were discovered by spectroscopic means. They are widely used to determine the physical conditions of stars and other celestial bodies that cannot be analyzed by other means.

Emission spectrum of Iron

Absorption spectrum of Iron

The electron affinity of Iron is 15.7 kJ/mol.

Ionization Energy of Iron

Ionization energy is the amount of energy required to remove an electron from an atom or molecule.in chemistry, this energy is expresed in kilocalories per mole (kcal/mol) or kilojoules per mole (kJ/mol).

Refer to table below for Ionization energies of Iron

Refer to below table for Iron Physical Properties

Elastic Properties

Hardness of Iron - Tests to Measure of Hardness of Element

Iron Electrical Properties

Electrical resistivity measures element's electrical resistance or how strongly it resists electric current.The SI unit of electrical resistivity is the ohm-metre (Ω⋅m). While Electrical conductivity is the reciprocal of electrical resistivity. It represents a element's ability to conduct electric current. The SI unit of electrical conductivity is siemens per metre (S/m).

Iron is a conductor of electricity. Refer to table below for the Electrical properties of Iron

Iron Heat and Conduction Properties

Iron Magnetic Properties

Optical Properties of Iron

Acoustic Properties of Iron

Refer to table below for Thermal properties of Iron

Enthalpies of Iron

Iron has 28 isotopes, with between 45 and 72 nucleons. Iron has 4 stable naturally occuring isotopes.

Isotopes of Iron - Naturally occurring stable Isotopes: 54Fe, 56Fe, 57Fe, 58Fe.

The United States Department of Transportation (DOT) identifies hazard class of all dangerous elements/goods/commodities either by its class (or division) number or name. The DOT has divided these materials into nine different categories, known as Hazard Classes.

NFPA 704 is a Standard System for the Identification of the Hazards of Materials for Emergency Response. NFPA is a standard maintained by the US based National Fire Protection Association.

The health (blue), flammability (red), and reactivity (yellow) rating all use a numbering scale ranging from 0 to 4. A value of zero means that the element poses no hazard; a rating of four indicates extreme danger.

List of unique identifiers to search the element in various chemical registry databases