Iron nitrides are inorganic chemical compounds of

iron Iron () is a chemical element with Symbol (chemistry), symbol Fe (from la, Wikt:ferrum, ferrum) and atomic number 26. It is a metal that belongs to the first transition series and group 8 element, group 8 of the periodic table. It is, Abundanc ...

and

nitrogen Nitrogen is the chemical element with the symbol N and atomic number 7. Nitrogen is a nonmetal and the lightest member of group 15 of the periodic table, often called the pnictogens. It is a common element in the universe, estimated at se ...

Chemical properties

Iron has five

nitride In chemistry, a nitride is an inorganic compound of nitrogen. The "nitride" anion, N3- ion, is very elusive but compounds of nitride are numerous, although rarely naturally occuring. Some nitrides have a find applications, such as wear-resistant ...

s observed at ambient conditions, Fe₂N, Fe₃N₄, Fe₄N, Fe₇N₃ and Fe₁₆N₂. They are

crystal A crystal or crystalline solid is a solid material whose constituents (such as atoms, molecules, or ions) are arranged in a highly ordered microscopic structure, forming a crystal lattice that extends in all directions. In addition, macro ...

line,

metal A metal (from Greek μέταλλον ''métallon'', "mine, quarry, metal") is a material that, when freshly prepared, polished, or fractured, shows a lustrous appearance, and conducts electricity and heat relatively well. Metals are typicall ...

lic solids.

Group 7 Group 7 may refer to: * G7, an international group of finance minister *Group 7 element, chemical element classification *Halogens (alternative name) *Group 7 Rugby League, rugby league competition in New South Wales, Australia *Group 7 (racing) G ...

and

group 8 Group 8 may refer to: * Group 8 element, a series of elements in the Periodic Table * Group 8 Rugby League, a rugby league competition * Group 8 (Sweden), a feminist movement in Sweden * Group VIII, former nomenclature for the noble gas The n ...

transition metal In chemistry, a transition metal (or transition element) is a chemical element in the d-block of the periodic table (groups 3 to 12), though the elements of group 12 (and less often group 3) are sometimes excluded. They are the elements that ca ...

s form nitrides that decompose at relatively low temperatures – iron nitride, Fe₂N decomposes under loss of molecular nitrogen at around 400 °C and formation of lower-nitrogen content iron nitrides. They are

insoluble In chemistry, solubility is the ability of a substance, the solute, to form a solution with another substance, the solvent. Insolubility is the opposite property, the inability of the solute to form such a solution. The extent of the solubil ...

water Water (chemical formula ) is an Inorganic compound, inorganic, transparent, tasteless, odorless, and Color of water, nearly colorless chemical substance, which is the main constituent of Earth's hydrosphere and the fluids of all known living ...

. At high pressure, stability and formation of new nitrogen-rich nitrides (N/Fe ratio equal or greater to one) were suggested and later discovered. These include the FeN, FeN₂ and FeN₄ solids which become thermodynamically stable from 17.7 GPa, 72 GPa and 106 GPa, respectively.

Health hazards

When heated to decomposition or exposed to humidity, iron nitride may emit toxic fumes of

ammonia Ammonia is an inorganic compound of nitrogen and hydrogen with the formula . A stable binary hydride, and the simplest pnictogen hydride, ammonia is a colourless gas with a distinct pungent smell. Biologically, it is a common nitrogenous wa ...

. It is considered a moderate explosion hazard. Inhalation of iron nitride dust or powder may cause irritation to the respiratory system and possibly acute

iron poisoning Iron poisoning typically occurs from ingestion of excess iron that results in acute toxicity. Mild symptoms which occur within hours include vomiting, diarrhea, abdominal pain, and drowsiness. In more severe cases, symptoms can include tachypnea, l ...

or pneumoconiosis.

Research applications

Colloidal solution of magnetic iron nitride

nanoparticle A nanoparticle or ultrafine particle is usually defined as a particle of matter that is between 1 and 100 nanometres (nm) in diameter. The term is sometimes used for larger particles, up to 500 nm, or fibers and tubes that are less than 10 ...

s is a way to create

ferrofluid Ferrofluid is a liquid that is attracted to the poles of a magnet. It is a colloidal liquid made of nanoscale ferromagnetic or ferrimagnetic particles suspended in a carrier fluid (usually an organic solvent or water). Each magnetic particle ...

s. Iron nitrides also make the strongest naturally magnetic material.

References

{{DEFAULTSORT:Iron Nitride Iron compounds Nitrides