Iron(III) chloride
IUPAC name	Iron(III) chloride
Other names	ferric chloride iron trichloride molysite (mineral) Flores martis
Identifiers
CAS number	[7705-08-0], hexahydrate: [10025-77-1]
RTECS number	LJ9100000
Properties
Molecular formula	FeCl3
Molar mass	162.2 g·mol-1 hexahydrate: 270.3 g·mol−1
Appearance	green-black by reflected light; purple-red by transmitted light hexahydrate: yellow solid aq. solutions: brown
Density	2.80 g·cm−3 40% solution: 1.4 g·ml−1
Melting point	306 °C, 579 K, 583 °F Iron(III) chloride hexahydrate This image has been released into the public domain by its creator and original copyright holder. ... Image File history File links Size of this preview: 800 × 551 pixelsFull resolution (1100 × 757 pixel, file size: 234 KB, MIME type: image/png) File historyClick on a date/time to view the file as it appeared at that time. ... Image File history File links Size of this preview: 782 × 599 pixelsFull resolution (1100 × 843 pixel, file size: 473 KB, MIME type: image/png) File historyClick on a date/time to view the file as it appeared at that time. ... IUPAC nomenclature is a system of naming chemical compounds and of describing the science of chemistry in general. ... CAS registry numbers are unique numerical identifiers for chemical compounds, polymers, biological sequences, mixtures and alloys. ... RTECS, also known as Registry of Toxic Effects of Chemical Substances, is a database of toxicity information compiled from the open scientific literature that is available for charge. ... A chemical formula is an easy way of expressing information about the atoms that constitute a particular chemical compound. ... Molar mass is the mass of one mole of a chemical element or chemical compound. ... For other uses, see Density (disambiguation). ... The melting point of a solid is the temperature range at which it changes state from solid to liquid. ...
Boiling point	315 °C, 588 K, 599 °F (partial decomposition to FeCl2+Cl2) Italic text This article is about the boiling point of liquids. ...
Solubility in water	92 g/100 ml (20 °C)
Solubility in acetone Methanol Ethanol Diethyl ether	63 g/100 ml (18 °C) highly soluble 83 g/100 ml highly soluble
Viscosity	40% solution: 12 cP
Structure
Crystal structure	hexagonal
Coordination geometry	octahedral
Hazards
Main hazards	Very corrosive
NFPA 704	0 3 1
R-phrases	R22, R34
S-phrases	S26, S28
Related compounds
Other anions	Iron(III) fluoride Iron(III) bromide
Other cations	Iron(II) chloride Manganese(II) chloride Cobalt(II) chloride Ruthenium(III) chloride
Related coagulants	Iron(II) sulfate Polyaluminium chloride
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) Infobox disclaimer and references

Iron(III) chloride, generically called ferric chloride, is an industrial scale commodity chemical compound, with the formula FeCl₃. The colour of iron(III) chloride crystals depends on the viewing angle: by reflected light the crystals appear dark green, but by transmitted light they appear purple-red. Anhydrous iron(III) chloride is deliquescent, forming hydrated hydrogen chloride mists in moist air. Solubility is a chemical property referring to the ability for a given substance, the solute, to dissolve in a solvent. ... Impact from a water drop causes an upward rebound jet surrounded by circular capillary waves. ... Solubility is a chemical property referring to the ability for a given substance, the solute, to dissolve in a solvent. ... For other uses, see Acetone (disambiguation). ... Methanol, also known as methyl alcohol, carbinol, wood alcohol, wood naphtha or wood spirits, is a chemical compound with chemical formula CH3OH (often abbreviated MeOH). ... Grain alcohol redirects here. ... This article is about the chemical compound. ... For other uses, see Viscosity (disambiguation). ... The poise (P; IPA: ) is the unit of dynamic viscosity in the centimetre gram second system of units. ... Enargite crystals In mineralogy and crystallography, a crystal structure is a unique arrangement of atoms in a crystal. ... A regular hexagon A hexagon (also known as sexagon) is a polygon with six edges and six vertices. ... The coordination geometry of an atom is the geometrical pattern formed by its neighbors in a molecule or a crystal. ... An octahedron (plural: octahedra) is a polyhedron with eight faces. ... The examples and perspective in this article or section may not represent a worldwide view. ... NFPA 704 is a standard maintained by the U.S. National Fire Protection Association. ... Image File history File links NFPA_704. ... R-phrases are defined in Annex III of European Union Directive 67/548/EEC: Nature of special risks attributed to dangerous substances and preparations. ... S-phrases are defined in Annex IV of European Union Directive 67/548/EEC: Safety advice concerning dangerous substances and preparations. ... This article is about the electrically charged particle. ... Iron(III) fluoride has formula FeF3. ... Iron tribromide is the chemical compound with the formula FeBr3, also known as ferric bromide or Iron(III) bromide. ... This article is about the electrically charged particle. ... Iron(II) chloride, or ferrous chloride, is the chemical compound FeCl2. ... Manganese(II) chloride (MnCl2) is a pink salt derived from the elments manganese and chlorine. ... Cobalt(II) chloride is the chemical compound with the formula CoCl2, although the term is used also to refer to the hexahydrate, which is a different chemical compound. ... Ruthenium(III) chloride is a dark brown or black solid which is commonly used as a starting material in ruthenium chemistry. ... A flocculant is a chemical which causes the particles in a colloidal dispersal to clump together and form flocs. Flocculants are commonly used to facilitate the removal by filtration of particles of impurity from a liquid which would otherwise be too fine to be caught by a filter. ... Iron(II) sulfate is the chemical compound with the formula (FeSO4). ... Aluminium chloride (AlCl3) is a compound of aluminium and chlorine. ... The plimsoll symbol as used in shipping In chemistry, the standard state of a material is its state at 1 bar (100 kilopascals exactly). ... In biological nomenclature, a generic name or the name of a genus (sometimes genus name) is the name of a genus. ... A chemical compound is a substance consisting of two or more different elements chemically bonded together in a fixed proportion by mass. ... Deliquescent materials are substances (mostly salts) which have a strong affinity for moisture and will absorb relatively large amount of water from the atmosphere if exposed to it, forming a liquid solution. ... R-phrases , S-phrases , , , , Flash point non-flammable Supplementary data page Structure and properties n, εr, etc. ...

When dissolved in water, iron(III) chloride undergoes hydrolysis and gives off heat in an exothermic reaction. The resulting brown, acidic, and corrosive solution is used as a coagulant in sewage treatment and drinking water production, and as an etchant for copper-based metals in printed circuit boards. Anhydrous iron(III) chloride is a fairly strong Lewis acid, and it is used as a catalyst in organic synthesis. Hydrolysis is a chemical reaction or process in which a chemical compound is broken down by reaction with water. ... In thermodynamics, the word exothermic outside heating describes a process or reaction that releases energy usually in the form of heat, but it can also release energy in form of light (e. ... For the hazard, see corrosive. ... A flocculant is a chemical which causes the particles in a colloidal dispersal to clump together and form flocs. Flocculants are commonly used to facilitate the removal by filtration of particles of impurity from a liquid which would otherwise be too fine to be caught by a filter. ... Sewage treatment, or domestic wastewater treatment, is the process of removing contaminants from wastewater, both runoff and domestic. ... A water treatment plant in northern Portugal. ... Etching is an intaglio method of printmaking in which the image is incised into the surface of a metal plate using an acid. ... Close-up photo of one side of a motherboard PCB, showing conductive traces, vias and solder points for through-hole components on the opposite side. ... In chemistry, a Lewis acid can accept a pair of electrons and form a coordinate covalent bond, after the American chemist Gilbert Lewis. ... Organic synthesis is the construction of organic molecules via chemical processes. ...

Chemical and physical properties

Iron(III) chloride has a relatively low melting point and boils at around 315 °C. The vapour consists of the dimer Fe₂Cl₆ (compare aluminium chloride) which increasingly dissociates into the monomeric FeCl₃ (D_3h point group molecular symmetry) at higher temperature, in competition with its reversible decomposition to give iron(II) chloride and chlorine gas.^[1] Aluminium chloride (AlCl3) is a compound of aluminium and chlorine. ... The symmetry group of an object (e. ... Molecular symmetry in chemistry describes symmetry in molecules and the classification of molecules in groups based on symmetry. ... Iron(II) chloride, or ferrous chloride, is the chemical compound FeCl2. ... General Name, symbol, number chlorine, Cl, 17 Chemical series nonmetals Group, period, block 17, 3, p Appearance yellowish green Standard atomic weight 35. ...

Reactions

Iron(III) chloride is a moderately strong Lewis acid, forming adducts with Lewis bases such as triphenylphosphine oxide, e.g. FeCl₃(OPPh₃)₂ where Ph = phenyl. In chemistry, a Lewis acid can accept a pair of electrons and form a coordinate covalent bond, after the American chemist Gilbert Lewis. ... Wikipedia does not yet have an article with this exact name. ... A Lewis base is any molecule or ion that can form a new covalent bond by donating a pair of electrons. ... Triphenylphosphine oxide usually appears as white crystals. ... In chemistry, the phenyl group or phenyl ring (often abbreviated as -Ph) is the functional group with the formula -C6H5 Picture where the six carbon atoms are arranged in a cyclic manner. ...

Iron(III) chloride reacts with other chloride salts to give the yellow tetrahedral FeCl₄⁻ ion. Salts of FeCl₄⁻ in hydrochloric acid can be extracted into diethyl ether. The chloride ion is formed when the element chlorine picks up one electron to form an anion (negatively-charged ion) Cl−. The salts of hydrochloric acid HCl contain chloride ions and can also be called chlorides. ... A tetrahedron (plural: tetrahedra) is a polyhedron composed of four triangular faces, three of which meet at each vertex. ... Hydrochloric acid is the aqueous solution of hydrogen chloride gas (HCl). ... This article is about the chemical compound. ...

When heated with iron(III) oxide at 350 °C, iron(III) chloride gives iron oxychloride, a layered solid and intercalation host. Iron(III) oxide — also known as ferric oxide, Hematite, red iron oxide, synthetic maghemite, colcothar, or simply rust — is one of the several oxide compounds of iron, and has paramagnetic properties. ... Intercalation is the insertioffn of an extra day, week or month into some calendar years to make the calendar follow the seasons. ...

FeCl₃ + Fe₂O₃ → 3 FeOCl

In the presence of base, alkali metal alkoxides react to give the dimeric complexes: An alkoxide is the conjugate base of an alcohol and therefore consists of an organic group bonded to a negatively charged oxygen atom. ... Sucrose, or common table sugar, is composed of glucose and fructose. ...

2 FeCl₃ + 6 C₂H₅OH + 6 NH₃ → (Fe(OC₂H₅)₃)₂ + 6 NH₄Cl

Oxalates react rapidly with aqueous iron(III) chloride to give [Fe(C₂O₄)₃]³⁻. Other carboxylate salts form complexes, e.g. citrate and tartrate. Grain alcohol redirects here. ... Ammonium chloride (NH4Cl) (also Sal Ammoniac, salmiac, nushadir salt, zalmiak, sal armagnac, sal armoniac, salmiakki, salmiak and salt armoniack) is, in its pure form, a clear white water-soluble crystalline salt of ammonia with a biting, slightly sour taste. ... Oxalic acid (IUPAC name: ethanedioic acid, formula C2H2O4) is a dicarboxylic acid with structure (HOOC)-(COOH). ... Structure of a carboxylic acid Carboxylic acids, also known as alkanoic acids, are organic acids characterized by the presence of a carboxyl group and have the general chemical formula R-C(=O)-OH, also written as R-COOH, where R is a hydrogen or an alkyl group. ... Citric acid is a weak organic acid found in citrus fruits. ... Tartaric acid is a white crystalline organic acid. ...

Iron(III) chloride is a mild oxidising agent, for example capable of oxidising copper(I) chloride to copper(II) chloride. Reducing agents such as hydrazine convert iron(III) chloride to complexes of iron(II). ed|other uses|reduction}} Illustration of a redox reaction Redox (shorthand for reduction/oxidation reaction) describes all chemical reactions in which atoms have their oxidation number (oxidation state) changed. ... Copper(I) chloride (quite commonly called cuprous chloride), is the lower chloride of copper, with the formula CuCl. ... Copper(II) chloride is the chemical compound with the formula CuCl2. ... Hydrazine is the chemical compound with formula N2H4. ...

Structure

Iron(III) chloride adopts the BiI₃ structure, which features octahedral Fe(III) centres interconnected by two-coordinate chloride ligands. An octahedron (plural: octahedra) is a polyhedron with eight faces. ...

Preparation and production

Anhydrous iron(III) chloride may be prepared by union of the elements:^[2]

2 Fe(s) + 3 Cl₂(g) → 2 FeCl₃(s)

Solutions of iron(III) chloride are produced industrially both from iron and from ore, in a closed-loop process. This box:      For other uses, see Solid (disambiguation). ... For other uses, see Gas (disambiguation). ...

1. Dissolving pure iron in a solution of iron(III) chloride
   Fe(s) + 2 FeCl₃(aq) → 3 FeCl₂(aq)
2. Dissolving iron ore in hydrochloric acid
   Fe₃O₄(s) + 8 HCl(aq) → FeCl₂(aq) + 2 FeCl₃(aq) + 4 H₂O
3. Upgrading the iron(II) chloride with chlorine
   2 FeCl₂(aq) + Cl₂(g) → 2 FeCl₃(aq)

Alternatively, iron(II) chloride can be oxidised with sulfur dioxide: Fe redirects here. ... This heap of iron ore pellets will be used in steel production. ... Hydrochloric acid is the aqueous solution of hydrogen chloride gas (HCl). ... Iron(II) chloride, or ferrous chloride, is the chemical compound FeCl2. ... General Name, symbol, number chlorine, Cl, 17 Chemical series nonmetals Group, period, block 17, 3, p Appearance yellowish green Standard atomic weight 35. ... Sulfur dioxide (or Sulphur dioxide) has the chemical formula SO2. ...

32 FeCl₂ + 8 SO₂ + 32 HCl → 32 FeCl₃ + S₈ + 16 H₂O

Like many other hydrated metal chlorides, hydrated iron(III) chloride can be converted to the anhydrous salt by refluxing with thionyl chloride.^[3] The hydrate cannot be converted to anhydrous iron(III) chloride by only heat, as instead HCl is evolved and iron oxychloride forms. R-phrases , , , S-phrases , , , Flash point non flammable Supplementary data page Structure and properties n, εr, etc. ...

Uses

Industrial

In industrial application, iron(III) chloride is used in sewage treatment and drinking water production.^[4] In this application, FeCl₃ in slightly basic water reacts with the hydroxide ion to form a floc of iron(III) hydroxide, or more precisely formulated as FeO(OH)^-, that can remove suspended materials. Sewage treatment, or domestic wastewater treatment, is the process of removing contaminants from wastewater, both runoff and domestic. ... A water treatment plant in northern Portugal. ... Hydroxide is a polyatomic ion consisting of oxygen and hydrogen: OH− It has a charge of −1. ... This article needs additional references or sources for verification. ...

Fe³⁺ + 4 OH⁻ → Fe(OH)₄⁻ → FeO(OH)₂⁻·H₂O

Another important application of iron(III) chloride is etching copper in two-step redox reaction to copper(I) chloride and then to copper(II) chloride in the production of printed circuit boards.^[5] For other uses, see Copper (disambiguation). ... ed|other uses|reduction}} Illustration of a redox reaction Redox (shorthand for reduction/oxidation reaction) describes all chemical reactions in which atoms have their oxidation number (oxidation state) changed. ... Copper(I) chloride (quite commonly called cuprous chloride), is the lower chloride of copper, with the formula CuCl. ... Copper(II) chloride is the chemical compound with the formula CuCl2. ... Close-up photo of one side of a motherboard PCB, showing conductive traces, vias and solder points for through-hole components on the opposite side. ...

FeCl₃ + Cu → FeCl₂ + CuCl

FeCl₃ + CuCl → FeCl₂ + CuCl₂

Iron(III) chloride is used as catalyst for the reaction of ethylene with chlorine, forming ethylene dichloride (1,2-dichloroethane), an important commodity chemical, which is mainly used for the industrial production of vinyl chloride, the monomer for making PVC. Ethylene (or IUPAC name ethene) is the chemical compound with the formula C2H4. ... General Name, symbol, number chlorine, Cl, 17 Chemical series nonmetals Group, period, block 17, 3, p Appearance yellowish green Standard atomic weight 35. ... The chemical compound 1,2-dichloroethane, commonly known by its old name of ethylene dichloride (EDC), is a chlorinated hydrocarbon, mainly used to produce vinyl chloride monomer (VCM, chloroethene), the major precursor for PVC production. ... Vinyl chloride, also known as chloroethene in IUPAC nomenclature, is an important industrial chemical chiefly used to produce its polymer, polyvinyl chloride (PVC). ... A monomer (from Greek mono one and meros part) is a small molecule that may become chemically bonded to other monomers to form a polymer [1]. // Examples of monomers are hydrocarbons such as the alkene and arene homologous series. ... PVC redirects here. ...

H₂C=CH₂ + Cl₂ → ClCH₂CH₂Cl

Laboratory use

In the laboratory iron(III) chloride is commonly employed as a Lewis acid for catalysing reactions such as chlorination of aromatic compounds and Friedel-Crafts reaction of aromatics. It is less powerful than aluminium chloride, but in some cases this mildness leads to higher yields, for example in the alkylation of benzene: In chemistry, a Lewis acid can accept a pair of electrons and form a coordinate covalent bond, after the American chemist Gilbert Lewis. ... It has been suggested that this article or section be merged into Catalysis. ... Chlorination is the process of adding the element chlorine to water as a method of water purification to make it fit for human consumption as drinking water. ... The term aromatic compound may also refer to: any organic compound possessing a strong olfactory aroma aromatic hydrocarbons (originally named as a subset of the above; however, aromatic hydrocarbons do not necessarily possess any smell whatsoever) ... The Friedel-Crafts reactions are a set of reactions developed by Charles Friedel and James Crafts in 1877. ... Aluminium chloride (AlCl3) is a compound of aluminium and chlorine. ...

An example of a Friedel-Crafts alkylation catalysed by iron(III) chloride, taken from B. S. Furnell et al. ...

The ferric chloride test is a traditional colorimetric test for phenols, which uses a 1% iron(III) chloride solution that has been neutralised with sodium hydroxide until a slight precipitate of FeO(OH) is formed.^[6] The mixture is filtered before use. The organic substance is dissolved in water, methanol or ethanol, then the neutralised iron(III) chloride solution is added—a transient or permanent coloration (usually purple, green or blue) indicates the presence of a phenol or enol. In organic chemistry, phenols, sometimes called phenolics, are a class of chemical compounds consisting of a hydroxyl group (-O H) attached to an aromatic hydrocarbon group. ... Sodium hydroxide (NaOH), also known as lye, caustic soda and (incorrectly, according to IUPAC nomenclature)[1] sodium hydrate, is a caustic metallic base. ... Methanol, also known as methyl alcohol, carbinol, wood alcohol, wood naphtha or wood spirits, is a chemical compound with chemical formula CH3OH (often abbreviated MeOH). ... Grain alcohol redirects here. ...

Other uses

• Anhydrous iron(III) chloride is sometimes used as a drying reagent in certain reactions.
• Iron(III) chloride is sometimes used by American coin collectors to identify the dates of Buffalo nickels that are so badly worn that the date is no longer visible.
• Iron(III) chloride is commonly used by knife craftsmen and sword smiths to stain blades, as to give a contrasting effect to the metal, and to view metal layering or imperfections.
• Iron(III) chloride is often used to etch the widmanstatten pattern in Iron Meteorites .
• Iron(III) chloride is necessary for the etching of photogravure plates for printing photographic and fine art images in intaglio and for etching rotogravure cylinders used in the printing industry.
• Iron(III) chloride is used in veterinary practice to treat overcropping of an animal's claws, particularly when the overcropping results in bleeding.
• Iron(III) chloride reacts with cyclopentadienylmagnesium bromide in one preparation of ferrocene, a metal-sandwich complex.^[7]
• Iron(III) chloride is sometimes used in the technique of Raku Firing as an additive during the reduction process, turning a pottery piece a burnt orange color due to the iron content present in the reducing atmosphere.

The United States five cent coin, commonly called a nickel, is a unit of currency equaling one 1/20th of a United States dollar. ... Worlds second largest Meteorite in Culiacan, Mexico A meteorite is a relatively small extra-terrestrial body that reaches the Earths surface. ... Photogravure is a type of intaglio printing process used for reproducing monochromatic (black and white) images. ... Intaglio is a printmaking technique in which the image is incised into a surface. ... Diagram of rotogravure process Rotogravure (gravure for short) is a type of intaglio printing process, in that it involves engraving the image onto an image carrier. ... Ferrocene is the chemical compound with the formula Fe(C5H5)2. ... A 16th century black Raku-style chawan, used for thick tea (Tokyo National Museum) Rakuyaki (樂焼き) or Raku (樂) is a form of Japanese pottery characterized by low firing temperatures (resulting in a fairly porous body), lead glazes, and the removal of pieces from the kiln while still glowing hot. ...

Safety

Iron(III) chloride is toxic, highly corrosive and acidic. The anhydrous material is a powerful dehydrating agent.

See also

• iron(II) sulfate
• aluminium chloride

Iron(II) sulfate is the chemical compound with the formula (FeSO4). ... Aluminium chloride (AlCl3) is a compound of aluminium and chlorine. ...

References

A digital object identifier (or DOI) is a standard for persistently identifying a piece of intellectual property on a digital network and associating it with related data, the metadata, in a structured extensible way. ... Akzo Nobel is a multinational company, active in the fields of healthcare products, coatings and chemicals. ... Year 2007 (MMVII) was a common year starting on Monday of the Gregorian calendar in the 21st century. ... is the 299th day of the year (300th in leap years) in the Gregorian calendar. ... Butterworth-Heinemann was a UK-based international publishing company specialized in professional information and learning materials for higher education and professional training, in printed and electronic forms. ... Longman is a firm of English publishers. ... Look up Wiley in Wiktionary, the free dictionary. ...

Further reading

1. Handbook of Chemistry and Physics, 71st edition, CRC Press, Ann Arbor, Michigan, 1990.
2. The Merck Index, 7th edition, Merck & Co, Rahway, New Jersey, USA, 1960.
3. D. Nicholls, Complexes and First-Row Transition Elements, Macmillan Press, London, 1973.
4. A.F. Wells, 'Structural Inorganic Chemistry, 5th ed., Oxford University Press, Oxford, UK, 1984.
5. J. March, Advanced Organic Chemistry, 4th ed., p. 723, Wiley, New York, 1992.
6. Handbook of Reagents for Organic Synthesis: Acidic and Basic Reagents, (H. J. Reich, J. H. Rigby, eds.), Wiley, New York, 1999.