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| {{short description|Iron in its +2 oxidation state}} | | {{Short description|Overview of ferrous materials and their applications}} |
| {{For|ferrous metals and alloys|Ferrous metallurgy}}
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| {{Redirect|Reduced iron|the elemental powder|Direct reduced iron}}
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| [[File:Eisen(II)-chlorid-Tetrahydrat.jpg|thumb|Iron(II) chloride tetrahydrate, {{chem2|FeCl2*4H2O}}.]]
| | ==Overview== |
| | The term '''ferrous''' is derived from the Latin word "ferrum," meaning iron. In the context of materials science and metallurgy, ferrous refers to metals and alloys that contain iron. These materials are characterized by their magnetic properties and are typically prone to rust when exposed to moisture and air. Ferrous metals are widely used in various industries due to their strength, durability, and versatility. |
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| In [[chemistry]], '''iron(II)''' refers to the [[chemical element|element]] [[iron]] in its +2 [[oxidation number|oxidation state]]. The adjective '''''ferrous''''' or the prefix '''''ferro-''''' is often used to specify such compounds, as in ''ferrous chloride'' for [[iron(II) chloride]] ({{chem2|FeCl2}}). The adjective ''[[ferric]]'' is used instead for [[iron(III)]] salts, containing the cation Fe<sup>3+</sup>. The word ''[[wikt:ferric|ferrous]]'' is derived from the [[Latin]] word {{wikt-lang|la|ferrum}}, meaning "iron".
| | ==Properties== |
| | Ferrous metals are known for their high tensile strength and durability. They are generally magnetic, which makes them useful in applications requiring magnetic properties. However, ferrous metals are also susceptible to corrosion, particularly when exposed to moisture and oxygen, leading to the formation of rust. This is a significant consideration in their use and storage. |
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| In [[salt (chemistry)|ionic compounds]] (salts), such an atom may occur as a separate [[cation]] (positive ion) abbreviated as '''Fe<sup>2+</sup>''', although more precise descriptions include other ligands such as water and halides. Iron(II) centres occur in [[coordination complex]]es, such as in the [[anion]] [[ferrocyanide]], {{chem2|[Fe(CN)6](4-)}}, where six [[cyanide]] ligands are bound the metal centre; or, in [[organometallic compound]]s, such as the [[ferrocene]] {{chem2|[Fe(C2H5)2]}}, where two [[cyclopentadienyl]] anions are bound to the Fe<sup>II</sup> centre.
| | ==Types of Ferrous Metals== |
| | Ferrous metals can be broadly categorized into several types, each with distinct properties and applications: |
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| ==Ferrous ions in biology== | | ===Cast Iron=== |
| {{main article|Iron metabolism}}
| | [[Cast iron]] is an alloy of iron, carbon, and silicon. It is known for its excellent castability, machinability, and wear resistance. Cast iron is commonly used in the manufacturing of pipes, automotive components, and cookware. |
| All known forms of life require iron.<ref>{{cite web | title = Iron integral to the development of life on Earth – and the possibility of life on other planets | url = https://www.ox.ac.uk/news/2021-12-07-iron-integral-development-life-earth-and-possibility-life-other-planets | date = 7 December 2021 | publisher = [[University of Oxford]] | accessdate = 9 May 2022}}</ref> Many [[protein]]s in living beings contain iron(II) centers. Examples of such [[metalloprotein]]s include [[hemoglobin]], [[ferredoxin]], and the [[cytochrome]]s. In many of these proteins, Fe(II) converts reversibly to Fe(III).<ref>{{cite book |author=Berg, Jeremy Mark |author2=Lippard, Stephen J. |title=Principles of bioinorganic chemistry |publisher=University Science Books |location=Sausalito, Calif |year=1994 |isbn=0-935702-73-3 }}</ref>
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| Insufficient iron in the human diet causes [[anemia]]. Animals and humans can obtain the necessary iron from foods that contain it in assimilable form, such as meat. Other organisms must obtain their iron from the environment. However, iron tends to form highly insoluble iron(III) oxides/hydroxides in aerobic ([[oxygen]]ated) environment, especially in [[calcareous soil]]s. [[Bacteria]] and [[graminaceae|grass]]es can thrive in such environments by secreting compounds called [[siderophore]]s that form soluble complexes with iron(III), that can be reabsorbed into the cell. (The other plants instead encourage the growth around their roots of certain bacteria that [[redox|reduce]] iron(III) to the more soluble iron(II).)<ref name=marsch94>H. Marschner and V. Römheld (1994): "Strategies of plants for acquisition of iron". ''Plant and Soil'', volume 165, issue 2, pages 261–274. {{doi|10.1007/BF00008069}}</ref>[[File:Pourbaix Diagram of Iron.svg|thumb|[[Pourbaix diagram]] of aqueous iron]]In contrast to iron(III) aquo complexes, iron(II) aquo complexes are soluble in water near neutral pH.{{citation needed|date=April 2024}} Ferrous iron is, however, oxidized by the oxygen in air, converting to iron(III).<ref>{{cite encyclopedia|last=Petsch|first=S.T.|title=Treatise on Geochemistry|edition=Second|year=2014|volume=10|series=Reference Module in Earth Systems and Environmental Sciences|pages=437-473|isbn=978-0-08-095975-7|chapter=10.11 - The Global Oxygen Cycle|doi=10.1016/B978-0-08-095975-7.00811-1|editor-last1=Holland|editor-first1=H.D.|editor-last2=Turekian|editor-first2=K.K.|publisher=Elsevier}}</ref>
| | ===Steel=== |
| | [[Steel]] is an alloy of iron and carbon, with varying amounts of other elements such as manganese, chromium, and nickel. Steel is one of the most widely used materials in the world, known for its strength and versatility. It is used in construction, automotive, and numerous other industries. |
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| ==Ferrous salts and complexes== | | ===Wrought Iron=== |
| Typically iron(II) salts, like the "[[iron(II) chloride|chloride]]" are [[aquo complex]]es with the formulas {{chem2|[Fe(H2O)6](2+)}}, as found in [[ferrous ammonium sulfate]].<ref name="earn">{{cite book |author=Earnshaw, A. |author2=Greenwood, N. N. |title=Chemistry of the elements |publisher=Butterworth-Heinemann |location=Oxford |year=1997 |isbn=0-7506-3365-4 |edition=2nd}}</ref>
| | [[Wrought iron]] is a form of iron with a very low carbon content. It is tough, malleable, and resistant to corrosion. Wrought iron is traditionally used for decorative purposes, such as in fences and railings. |
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| The aquo ligands on iron(II) complexes are labile. It reacts with [[1,10-Phenanthroline|1,10-phenanthroline]] to give the blue iron(II) derivative:
| | ==Applications== |
| | Ferrous metals are integral to many industries due to their mechanical properties and cost-effectiveness. Some common applications include: |
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| When metallic iron (oxidation state 0) is placed in a solution of [[hydrochloric acid]], iron(II) chloride is formed, with release of [[hydrogen]] gas, by the reaction
| | * '''Construction''': Steel is a primary material in the construction of buildings, bridges, and infrastructure due to its strength and durability. |
| : {{chem2|Fe^{0} + 2 H(+) -> Fe(2+) + H2}} | | * '''Automotive''': Ferrous metals are used in the manufacturing of car bodies, engines, and other components. |
| | * '''Machinery''': The strength and machinability of ferrous metals make them ideal for use in industrial machinery and tools. |
| | * '''Railways''': Steel is used extensively in the construction of railway tracks and train components. |
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| Iron(II) is oxidized by hydrogen peroxide to [[iron(III)]], forming a [[hydroxyl radical]] and a [[hydroxide ion]] in the process. This is the [[Fenton reaction]]. Iron(III) is then reduced back to iron(II) by another molecule of hydrogen peroxide, forming a [[hydroperoxyl]] radical and a [[hydrogen atom|proton]]. The net effect is a [[disproportionation]] of hydrogen peroxide to create two different oxygen-radical species, with water (H<sup>+</sup> + OH<sup>−</sup>) as a byproduct.<ref>{{cite journal |doi=10.1021/acs.chemrev.0c00977 |title=Biomedicine Meets Fenton Chemistry |date=2021 |last1=Tang |first1=Zhongmin |last2=Zhao |first2=Peiran |last3=Wang |first3=Han |last4=Liu |first4=Yanyan |last5=Bu |first5=Wenbo |journal=Chemical Reviews |volume=121 |issue=4 |pages=1981–2019 |pmid=33492935 |s2cid=231712587 }}</ref>
| | ==Corrosion and Protection== |
| | One of the main challenges with ferrous metals is their tendency to corrode. Corrosion can be mitigated through various methods, such as: |
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| {{NumBlk|:| Fe<sup>2+</sup> + H<sub>2</sub>O<sub>2</sub> → Fe<sup>3+</sup> + HO<sup>•</sup> + OH<sup>−</sup>|{{EquationRef|1}}}}
| | * '''Galvanization''': Coating the metal with a layer of zinc to prevent rusting. |
| {{NumBlk|:| Fe<sup>3+</sup> + H<sub>2</sub>O<sub>2</sub> → Fe<sup>2+</sup> + HOO<sup>•</sup> + H<sup>+</sup>|{{EquationRef|2}}}}
| | * '''Painting''': Applying protective coatings to shield the metal from moisture and oxygen. |
| | * '''Alloying''': Adding elements like chromium to create stainless steel, which is more resistant to corrosion. |
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| The [[free radical]]s generated by this process engage in secondary reactions, which can degrade many organic and biochemical compounds.[[File:Fe(bipy)3 redox.svg|thumb|360px|center|Redox reaction of [Fe(bipyridine)<sub>3</sub>]<sup>2+</sup>.]]
| | ==Related Pages== |
| ==Ferrous minerals and other solids== | | * [[Iron]] |
| [[File:Iron(II) oxide.jpg|thumb|Iron(II) oxide (ferrous oxide), FeO, is a very complicated material that contains iron(II).]] | | * [[Steel]] |
| | | * [[Corrosion]] |
| Iron(II) is found in many minerals and solids. Examples include the sulfide and oxide, FeS and FeO. These formulas are deceptively simple because these sulfides and oxides are often [[nonstoichiometric]]. For example, "ferrous sulfide" can refer to the 1:1 species (mineral name [[troilite]]) or a host of Fe-deficient derivatives ([[pyrrhotite]]). The mineral [[magnetite]] ("lode stone") is a mixed-valence compound with both Fe(II) and Fe(III), Fe<sub>3</sub>O<sub>4</sub>.
| | * [[Metallurgy]] |
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| ==Bonding==
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| [[File:L.s. vs h.s. d6 octahedral.svg|thumb|d-orbital splitting scheme for low- and high spin octahedral Fe(II) complexes.]]Iron(II) is a d<sup>6</sup> center, meaning that the metal has six "valence" electrons in the 3d orbital shell. The number and type of ligands bound to iron(II) determine how these electrons arrange themselves. With the so-called "strong field ligands" such as [[cyanide]], the six electrons pair up. Thus [[ferrocyanide]] ({{chem2|[Fe(CN)6](4-)}} has no unpaired electrons, meaning it is a low-spin complex. With so-called "weak field ligands" such as [[water]], four of the six electrons are unpaired, meaning it is a [[High Spin Complex|high-spin]] complex. Thus [[aquo complex]] {{chem2|[Fe(H2O)6](2+)}} is [[paramagnetic]]. With [[chloride]], iron(II) forms tetrahedral complexes, e.g. {{chem2|[FeCl4](2-)}}. Tetrahedral complexes are high-spin complexes. | |
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| ==Gallery==
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| {{Gallery
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| | title = Selected Fe(II) compounds
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| | File:Iron(II) nitrate hexahydrate.jpg
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| | [[Iron(II) nitrate|Ferrous nitrate hexahydrate]], Fe(NO<sub>3</sub>)<sub>2</sub>·6H<sub>2</sub>O
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| | File:Iron(II)-oxalate-sample.jpg
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| | [[Ferrous oxalate|Ferrous oxalate dihydrate]], [[Humboldtine]], FeC<sub>2</sub>O<sub>4</sub>·2H<sub>2</sub>O
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| | File:7314M-vivianite2.jpg
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| | [[Vivianite]], Ferrous phosphate octahydrate, Fe<sub>3</sub>(PO<sub>4</sub>)<sub>2</sub>·8H<sub>2</sub>O
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| | File:Ferrous_sulfate.jpg
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| | [[Iron(II) sulfate|Ferrous sulfate heptahydrate]], [[Melanterite]], FeSO<sub>4</sub>·7H<sub>2</sub>O
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| | File:Iron(II)-sulfide-sample.jpg
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| | [[Iron(II) sulfide|Ferrous sulfide]], [[Troilite]], FeS
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| | FeSiO3.png
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| | Ferrous silicate, [[Ferrosilite]], FeSiO<sub>3</sub>
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| }}
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| ==See also==
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| * {{annotated link|Ferric}} — [Iron(III)] compounds
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| * {{annotated link|Ferromagnetism}}
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| * {{annotated link|Ferrous metal recycling}}
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| * {{annotated link|Iron(II) oxide}} (ferrous oxide)
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| * {{annotated link|Iron(II) bromide}} (ferrous bromide)
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| * {{annotated link|Steelmaking}}
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| ==References==
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| {{wiktionary|ferrous|nonferrous}}
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| {{reflist|30em}}
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| | [[Category:Metallurgy]] |
| | [[Category:Materials science]] |
| [[Category:Iron]] | | [[Category:Iron]] |
| [[Category:Iron(II) compounds| ]]
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| [[Category:Chemical compounds by element]]
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Overview of ferrous materials and their applications
Overview[edit]
The term ferrous is derived from the Latin word "ferrum," meaning iron. In the context of materials science and metallurgy, ferrous refers to metals and alloys that contain iron. These materials are characterized by their magnetic properties and are typically prone to rust when exposed to moisture and air. Ferrous metals are widely used in various industries due to their strength, durability, and versatility.
Properties[edit]
Ferrous metals are known for their high tensile strength and durability. They are generally magnetic, which makes them useful in applications requiring magnetic properties. However, ferrous metals are also susceptible to corrosion, particularly when exposed to moisture and oxygen, leading to the formation of rust. This is a significant consideration in their use and storage.
Types of Ferrous Metals[edit]
Ferrous metals can be broadly categorized into several types, each with distinct properties and applications:
Cast Iron[edit]
Cast iron is an alloy of iron, carbon, and silicon. It is known for its excellent castability, machinability, and wear resistance. Cast iron is commonly used in the manufacturing of pipes, automotive components, and cookware.
Steel is an alloy of iron and carbon, with varying amounts of other elements such as manganese, chromium, and nickel. Steel is one of the most widely used materials in the world, known for its strength and versatility. It is used in construction, automotive, and numerous other industries.
Wrought Iron[edit]
Wrought iron is a form of iron with a very low carbon content. It is tough, malleable, and resistant to corrosion. Wrought iron is traditionally used for decorative purposes, such as in fences and railings.
Applications[edit]
Ferrous metals are integral to many industries due to their mechanical properties and cost-effectiveness. Some common applications include:
- Construction: Steel is a primary material in the construction of buildings, bridges, and infrastructure due to its strength and durability.
- Automotive: Ferrous metals are used in the manufacturing of car bodies, engines, and other components.
- Machinery: The strength and machinability of ferrous metals make them ideal for use in industrial machinery and tools.
- Railways: Steel is used extensively in the construction of railway tracks and train components.
Corrosion and Protection[edit]
One of the main challenges with ferrous metals is their tendency to corrode. Corrosion can be mitigated through various methods, such as:
- Galvanization: Coating the metal with a layer of zinc to prevent rusting.
- Painting: Applying protective coatings to shield the metal from moisture and oxygen.
- Alloying: Adding elements like chromium to create stainless steel, which is more resistant to corrosion.
Related Pages[edit]
