- Structure
- Nomenclature
- Properties
- Physical state
- Molecular weight
- Melting point
- Boiling point
- Density
- Solubility
- pH
- Chemical properties
- Obtaining
- Presence in nature
- Applications
- In wastewater treatment
- In veterinary curative procedures
- In the extraction of metals
- As a chemical and biological laboratory reagent
- In various applications
- Risks
- References
The iron chloride (III) is an inorganic compound consisting of the elements iron (Fe) and chlorine (Cl). Its chemical formula is FeCl 3. It is a crystalline solid whose color can be from orange to blackish brown.
FeCl 3 dissolves easily in water, forming acidic aqueous solutions in which increasing the pH, making them more alkaline, can form a solid of ferric oxide.
Iron (III) chloride or solid FeCl 3 ferric chloride. Егор Осин / CC BY-SA (https://creativecommons.org/licenses/by-sa/3.0). Source: Wikimedia Commons.
Iron (III) chloride is used to settle water-polluting particles from municipal or industrial waste. It is said that it allows the removal of some parasites and serves to stop blood loss from wounds in animals and for their healing.
It is used to extract copper (II) from copper sulphide ores. It is also used in various chemical reactions and analyzes in biological and chemical laboratories. For example, it is used to detect compounds such as phenols in oils extracted from plants. It is used in electronic circuits, in leather tanning and in photography.
Because FeCl 3 is an acid compound, it is corrosive to skin and mucous membranes. Breathing the dust of this compound should be avoided. It should not be disposed of in the environment.
Structure
Iron (III) chloride or FeCl 3 ferric chloride is an ionic compound and is made up of one Fe 3+ ferric ion and three Cl - chloride ions. Iron is in its oxidation state of +3 and each chlorine has a -1 valence.
Iron (III) chloride or ferric chloride. Author: Marilú Stea.
Nomenclature
- Iron (III) chloride
- Ferric chloride
- Iron trichloride
- Iron muriate
Properties
Physical state
Orange to blackish brown crystalline solid.
Ferric chloride FeCl 3 anhydrous (without water). Leiem / CC BY-SA (https://creativecommons.org/licenses/by-sa/4.0). Source: Wikimedia Commons.
Molecular weight
Anhydrous FeCl 3 = 162.2 g / mol
Melting point
Anhydrous FeCl 3 = 304 ºC
Hexahydrate FeCl 3 • 6H 2 O = 37 ° C
Boiling point
Anhydrous FeCl 3 = Approximately 316 ºC
FeCl 3 • 6H 2 O hexahydrate = 280-285 ° C
Density
Anhydrous FeCl 3 = 2.90 g / cm 3 at 25 ° C
Solubility
Very soluble in water: 74.4 g / 100 g of water at 0 ° C; 535.7 g / 100 g of water at 100 ° C. Very soluble in acetone, ethanol, ether and methanol. Weakly soluble in non-polar solvents such as benzene and hexane.
pH
Its aqueous solutions are very acidic. A solution of 0.1 moles of FeCl 3 per liter of water has a pH of 2.0.
Chemical properties
When the FeCl 3 is dissolved in water, it hydrolyzes; that is, it separates into its Fe 3+ and 3 Cl - ions. Fe 3+ forms the hexa-iron ion 3+ but this combines with the OH - ions from water forming mixed species and releasing H + protons.
For this reason their solutions are acidic. If the pH is increased, these species form a gel and finally a precipitate or solid of hydrated ferric oxide Fe 2 O 3 • nH 2 O forms.
Iron (III) chloride crystals are hygroscopic, that is, they absorb water from the environment. When wet it is corrosive to aluminum and many metals.
FeCl 3 solutions can be very acidic and corrosive, as they contain HCl. Kanesskong / CC BY-SA (https://creativecommons.org/licenses/by-sa/4.0). Source: Wikimedia Commons.
Aqueous FeCl 3 solutions are highly acidic and corrosive to most metals. They have a faint odor of hydrochloric acid HCl. When heated to decomposition, FeCl 3 emits highly toxic HCl gases.
Obtaining
Iron (III) chloride is produced by direct chlorination of iron by reacting dry chlorine (Cl 2) with scrap iron (Fe) at 500-700 ° C.
The reaction is carried out in an acid resistant reactor. The first step is to melt a mixture of iron (III) chloride (FeCl 3) and potassium chloride (KCl) at 600 ° C.
FeCl 3 must be prepared in highly acid-resistant containers such as stainless steel. Author: Johannes Plenio. Source: Pixabay.
Then the scrap iron (Fe) is dissolved in said molten mixture where the iron reacts with FeCl 3 and becomes ferrous chloride (FeCl 2).
Fe + 2 FeCl 3 → 3 FeCl 2
Then the FeCl 2 reacts with the chlorine Cl 2 forming the FeCl 3 which sublimates (goes directly from the solid to the gaseous state) and is collected in special condensation chambers.
2 FeCl 2 + Cl 2 → 2 FeCl 3
Ferrous sulfate FeSO 4 can also be reacted with chlorine Cl 2.
FeCl 3 • 6H 2 O hexahydrate can be obtained by evaporation of an aqueous solution of Fe 3+ and Cl - ions on a steam bath.
Presence in nature
Ferric chloride or iron (III) chloride is found in nature in the form of the mineral molysite, which is found in lava from active volcanoes. Among the volcanoes where it can be found is Mount Vesuvius.
FeCl 3 is part of the mineral molysite which is found in active volcanoes. Author: Skeeze. Source: Pixabay.
Applications
In wastewater treatment
Ferric chloride is used to treat municipal or industrial wastewater by chemical sedimentation.
It acts as a coagulant favoring the union of several particles with each other, in this way conglomerates or larger particles are formed that tend to flocculate or sediment (go down by their own weight to the bottom of the water being treated).
FeCl 3 is used to separate undesirable materials from wastewater by communities or industries. Author: 后 园 卓. Source: Pixabay.
In this way, the separation of solids from the water is favored and this is free of unwanted materials.
This type of treatment can facilitate the removal of parasites, such as protozoa, which are microorganisms formed by a single cell, such as amoebae, that cause disease.
For this reason, FeCl 3 is also used to purify water.
In veterinary curative procedures
Iron (III) chloride is used to heal animal wounds.
It serves as a local astringent (can retract tissues and act as an anti-inflammatory and healing) and hemostatic (stops bleeding or blood loss).
It is used in powders to stop blood loss or when cattle have had their horns cut off. It is also used in the form of a solution to stop bleeding when claws are cut or warts are removed.
FeCl 3 is used in powders applied to the cut horns of cows to prevent infection. Author: JacLou DL. Source: Pixabay.
It is also used to treat pharyngitis (inflammation of the pharynx) or stomatitis (inflammation of the oral mucosa) and to increase hemoglobin in the blood in some birds.
In the extraction of metals
Iron (III) chloride or ferric chloride FeCl 3 is used to extract copper (II) from copper ore containing copper sulphides.
It is an oxidative method that is suitable to avoid the release of the toxic gas sulfur dioxide (SO 2), since instead of this sulfur (S) is generated. Solutions are produced with high concentrations of FeCl 2, FeCl 3, CuCl 2 and other metal chlorides.
4 FeCl 3 + Cu 2 S ⇔ 4 FeCl 2 + 2 CuCl 2 + S ↓
As a chemical and biological laboratory reagent
Among many of its uses in chemistry, it serves to indicate the presence of the phenolic –OH group (that is, the –OH group attached to a benzene ring).
The compound to be analyzed is dissolved in ethanol and a few drops of FeCl 3 solution are added. When the compound has a -OH group attached to a benzene ring (that is, it is a phenol), a bluish-green color is formed.
This test allows to analyze the presence of phenols in plant extracts.
FeCl 3 in the presence of phenols gives a bluish-green color. Author: Ewa Urban. Source: Pixabay.
It is also used in tests to determine the antioxidant activity of certain oils extracted from vegetables.
Another of its applications is that it allows the preparation of other chemical compounds. It can also act as an oxidizing, chlorinating agent (providing chlorine) and condensing (to join two or more molecules together).
It also serves as a catalyst or accelerator for organic chemistry reactions.
In various applications
Ferric chloride is used in printed electronic circuits. Due to the coloration of its various hydrated forms, it serves as a pigment and is used in leather tanning.
FeCl 3 is used in leather tanning. Author: Pexels. Source: Pixabay.
It is disinfectant. It is used to treat skin disorders and is also used in photography.
Risks
FeCl 3 dust is irritating to the eyes, nose and mouth. If inhaled it may cause coughing or difficulty breathing. It is a corrosive compound, so prolonged contact with the skin and with the eyes or mucous membranes can cause redness and burns.
It is not flammable, but when heated to high temperatures it produces hydrogen chloride HCl gas, which is toxic and highly corrosive.
FeCl 3 is harmful to aquatic and terrestrial organisms. If by accident it is disposed of into the environment, its acidity must be neutralized with basic compounds.
References
- US National Library of Medicine. (2019). Ferric chloride. Recovered from pubchem.ncbi.nlm.nih.gov.
- Kirk-Othmer (1994). Encyclopedia of Chemical Technology. Volume 19. Fourth Edition. John Wiley & Sons.
- Ullmann's Encyclopedia of Industrial Chemistry. (1990). Fifth Edition. Volume A22. VCH Verlagsgesellschaft mbH.
- Ngameni, B. et al. (2013). Flavonoids and Related Compounds from the Medicinal Plants of Africa. Characterization of Flavonoids in Plant Extracts. Ferric Chloride Test. In Medicinal Plant Research in Africa. Recovered from sciencedirect.com.
- Agyare, C. et al. (2017). Petroselinum crispum: a Review. Antioxidant activity. In medicinal Spices and Vegetables from Africa. Recovered from sciencedirect.com.
- Stott, R. (2003). Fate and behavior of parasites in wastewater treatment systems. Chemically assisted sedimentation. In Handbook of Water and Wastewater Microbiology. Recovered from sciencedirect.com.
- Tasker, PA et al. (2003). Applications of Coordination Chemistry. Extraction of Cu II from chloride solutions. In Comprehensive Coordination Chemistry. Recovered from sciencedirect.com.
- Cotton, F. Albert and Wilkinson, Geoffrey. (1980). Advanced Inorganic Chemistry. Fourth Edition. John Wiley & Sons.