He Iron sulphate III , Also known as ferric sulphate, Mars vitriol or Martian caparrosa, is an inorganic compound of the formula Fe 2 (SO4) 3 . Each iron atom has three ionic bonds with the sulfate.
Ferric sulfate is found in a wide variety of minerals, mainly in pyrite or marcasite minerals, where ferrous sulfate is connected with ferrous oxide (Fe0).
Other minerals such as coquimbite, kornelite and lausenite are sources of ferric sulphate nona, hepta and pentahidratado. On the other hand, the ferric sulphate can be found in minerals like Mikasita, where a mixture is formed with aluminum (Ferric sulfate Formula, 2005-2017).
Figure 1: Structure of ferric sulphate.
Ferric sulfate is mostly extracted from nature; however, it can also be prepared by evaporation of ferric oxide and sulfuric acid. It is generally prepared by treating ferrous sulfate and an oxidizing agent with sulfuric acid at elevated temperatures in the following manner:
2FeSO 4 + H 2 SW 4 + H 2 OR 2 → Faith 2 (SW 4 ) 3 + 2H 2 OR
Ferric sulfate solutions are prepared by injecting gaseous chlorine into a ferrous sulfate solution.
In aqueous solution Fe 2 (SW 4 ) 3 Is dissociated in Fe 3+ (Aq) and SO 4 2- (Aq). The sulfate ions will be solvated by hydrogen bonds with the water and the iron ions will form the complex hexahydrate (III), [Fe (H2O) 6 ] 3+ (What happens to iron (III) sulfate (ferric sulfate) in aqueous solution?, 2015).
Physical and chemical properties
Ferric sulfate is a hygroscopic solid whose appearance and aroma may vary depending on the amount of water contained in the salt.
The most frequent forms in which iron (III) sulfate is found in nature are penta and nona hydrate. In such a case, the crystals of this compound may be yellow in color. When it is anhydrous it has a gray color (Ferric sulfate, 2016).
Figure 2: appearance of hydrated ferric sulphate (left) and anhydrous (der.).
Ferric sulfate molecules form rhombic or rhombohedral crystals. Its anhydrous form has a molecular weight of 399.858 g / mol, its hydrated penta and nona form have a molecular weight of 489,960 g / mol and 562,000 g / mol respectively (Royal Society of Chemistry, 2015).
Its density is 3.097 g / ml (anhydrous) and its melting point is 480 ° C (anhydrous) and 175 ° C (nonahydrated). It is slightly soluble in water and alcohol, while very little soluble in acetone and ethyl acetate and insoluble in sulfuric acid (National Center for Biotechnology Information, S.F.).
Iron sulphate III is acid, being corrosive to copper, copper alloys, mild steel and galvanized steel (FERRIC SULFATE, 2016).
Reactivity and hazards
Ferric sulfate is a stable non-flammable compound, however, when heated it emits toxic fumes of iron and sulfur oxides.
It is very dangerous in case of ingestion, contact with skin and eyes (irritant) and inhalation. The substance is toxic to the lungs and mucous membranes and repeated or prolonged exposure to the substance may cause damage to these organs.
In case of contact with eyes, contact lenses should be checked and removed. Eye ointment should not be used and medical attention should be sought.
In case of contact with the skin, it should be washed immediately with plenty of water in a gentle manner and with care not to use non-abrasive soap. Cover irritated skin with an emollient. If irritation persists, seek medical attention.
If contact with the skin is severe, it should be washed with a disinfectant soap and cover the skin contaminated with an anti-bacterial cream. Seek medical attention.
In case of inhalation, the victim should be allowed to stand in a well-ventilated area and seek immediate medical attention.
If swallowed, do not induce vomiting, but loosen tight clothing such as a collar, tie, or belt. If the victim is not breathing, mouth-to-mouth resuscitation should be performed. As in previous cases, you should seek immediate medical attention.
This type of compound does not require a specific type of storage. Shelves or cabinets that are strong enough to support the weight of the chemical are used, ensuring that no effort is required to reach the materials, and that the shelves are not overloaded (Material Safety Data Sheet Ferric Sulfate, 2013).
Applications
Ferric sulfate is used in industry, in water and wastewater treatment operations because of its ability as a flocculant and coagulant and to eliminate the odor of sulfur compounds.
Ferric sulphate is used as a solids removal agent and oxidizing agent. In addition, this salt is used in the pigment industry and in medicine, it can be used as astringent and estíptico.
In the work of Ibricevic (2000), 70 decayed primary molar teeth with no symptoms and no sign of root resorption were treated in children aged 3 to 6 years (main age: 4.3 years) treated with conventional pulpotomy. They used a 15.5% ferric sulphate solution (applied for 15 seconds for 35 teeth) and formocresol solution (a five minute procedure of the Buckley formula for the next 35 teeth) as pulpotomy agents.
In both groups, the pulp stumps were covered with eugenol zinc oxide paste. Permanent restorations were stainless steel crowns. The clinical control was every three months and the radiographic follow-up was six and twenty months after the treatment.
Results in this period revealed a 100% clinical success rate in both groups. The radiographic success rate was 97.2% in both groups, while in 2.8% the cases showed internal root resorption.
Ferric sulfate and jarosite have been detected by the two Martian Rovers Spirit and Opportunity. These substances are indicative of very oxidizing conditions that prevail on the surface of Mars.
References
- Ferric sulfate. (2016). Retrieved from chemicalbook: chemicalbook.com.
- FERRIC SULFATE. (2016). Retrieved from cameochemicals: cameochemicals.noaa.gov.
- Ferric sulfate Formula. (2005-2017). Retrieved from Softschools: Softschools.com.
- Ibricevic H1, a.-J. Q. (2000). Ferric sulfate pulpotomy agent in primary teeth: twenty-month clinical follow-up. Clin Pediatr Dent 24 (4), 269-272.
- Material Safety Data Sheet Ferric sulfate. (2013, May 21). Retrieved from sciencelab.
- National Center for Biotechnology Information. (S.F.). PubChem Compound Database; CID = 24826. Retrieved from PubChem.
- Royal Society of Chemistry. (2015). Iron (III) sulfate. Retrieved from chemspider.
- What happens to iron (III) sulfate (ferric sulfate) in aqueous solution? (2015, August 8). Retrieved from stackexchange: stackexchange.com.