Chemical and Physical Properties
Ferrous sulfate, also known as Ferrous sulphate or green vitriol, is a sulphate of ferrous iron with the chemical formula FeSO₄. It appears as a dull blue-green monoclinic crystalline powder or granules. Odourless, it possesses a salty, astringent taste. It deliquesces in dry air and readily oxidises to form brownish-yellow basic ferric sulphate in humid conditions. A 10% aqueous solution exhibits acidity towards litmus (pH approximately 3.7). Upon heating to 70–73°C, it loses three molecules of water; at 80–123°C, it loses six molecules of water; and above 156°C, it transforms into basic ferric sulphate. It is readily soluble in water (1g/1.5ml at 25°C or 1g/0.5ml in boiling water) but insoluble in ethanol.
Green vitriol refers to its heptahydrate form, FeSO₄·7H₂O, which contains 19% iron (Fe). The pure substance forms green crystals. Upon exposure to air, it gradually oxidises to form basic ferric sulphate, appearing yellowish-brown. It dissolves in water, yielding an acidic aqueous solution.
Ferrous sulphate exhibits strong acidity and is highly corrosive. It is generally soluble in water; when chlorides are present in the solution, a brownish precipitate forms, also known as iron sulphate rust. The crystalline hydrate of ferrous sulphate at room temperature is the heptahydrate (i.e., ferrous sulphate heptahydrate). The heptahydrate is a blue-green monoclinic crystal that loses six molecules of water of hydration at 64–90°C and is completely dehydrated at 300°C, undergoing partial decomposition simultaneously. It is corrosive, deliquescent in dry air, and readily oxidised by moist air. It is soluble in water (48 g/100 mL) and methanol, and slightly soluble in ethanol.
Uses
- Nutritional supplements (iron enhancer); color former of fruit and vegetable; for example, the salted product used together with dried alum in eggplant can form stable complex salt with its pigment to prevent the discoloration caused by organic acids. However, it should be noted, for example, it will turn into black ink upon excess amount of iron. When the amount of alum is high, the meat of the pickled eggplant meat will become excessively solid. Formulation example: long eggplant 300 kg; edible salt 40kg; ferrous sulfate 100g; dried alum 500g. It can still be used as the color forming agent of black beans, sugar boiled beans and kelp. Food containing tannins, in order to avoid of causing blackening, should not be used. It can also be used for sterilization, deodorization and very weakly bactericidal.
- Legumes contained cryptochromic pigment is colorless upon reduction state while being oxidized into black upon oxidation in alkaline condition. Taking advantage of the reduction property of ferrous sulfate can achieve the purpose of color protection with the usage amount of 0.02% to 0.03%.
- If is used for the manufacturing of iron salt, iron oxide pigments, mordant, purifying agent, preservatives, disinfectants and medicine for anti-anemia drugs
Toxicity
LD50: 279 to 558 mg/kg (rat, oral, calculated as Fe).
GRAS (FDA, § 182.5315, §184.1315, 2000);
ADI 0.8 mg Fe/kg (calculated in terms of Fe; FAO/WHO, 2001);
Hazards & Safety Information
Category :Toxic substances
Toxicity classification: highly toxic
Acute Toxicity : Oral-Rat LD50 319 mg/kg; Oral-mouse LD50: 680 mg/kg
Flammability and Hazardous characteristics: Non-combustible with fire producing toxic iron-containing fumes
Storage and transportation characteristics Treasury: low temperature, ventilated, dry; store separately from food raw materials.
Fire extinguishing agent : water, carbon dioxide, dry powder, sand
Occupational Standard :TWA 1 mg (iron)/m3
Description
Green vitriol (FeSO₄·7H₂O) has been known since the thirteenth century; it crystallizes from solutions of iron or iron bases in dilute sulfuric acid. The heptahydrate forms green monoclinic crystals with a density of 1.88 and is very soluble in water (296 g L⁻¹ FeSO₄ at 25 °C). The white monohydrate is obtained by precipitating the aqueous solution with ethanol, heating the heptahydrate to 140 °C in vacuo, or crystallizing it from 50% sulfuric acid. This can be further dehydrated to white, amorphous FeSO₄ by heating to 300 °C in a stream of hydrogen. At red heat, the sulfate decomposes:
2FeSO₄ → Fe₂O₃ + SO₂ + SO₃
A tetrahydrate (FeSO₄·4H₂O) crystallizes from aqueous solutions above 56 °C.
Chemical Properties
Ferrous sulfate is a greenish or yellowish solid in fine or lumpy crystals. It is odorless, soluble in water (with a saline taste), insoluble in alcohol, and hygroscopic.
Physical properties
White orthorhombic crystal; hygroscopic; density 3.65 g/cm
3; soluble in water (26.6g/100g water at 20°C). The monohydrate is a yellowish-white monoclinic crystal; density 3.0 g/cm
3; decomposes at 300°C; soluble in water. Heptahydrate is bluish-green monoclinic crystal; refractive index 1.47; hardness 2 Mohs; density 1.89g/cm
3; decomposes at about 60°C; very soluble in water; soluble in absolute methanol; slightly soluble in ethanol.
Occurrence
Iron(II) sulfate is probably the most important salt of iron, as well as the longest-known iron(II) compound. The compound is used as a mordant in dyeing; as a component of writing ink; in electroplating baths; in radiation dosimeters; in lithography and engraving; as a weed-killer; and in water purification. A major application of this compound is in the manufacture of other iron(II) salts including Prussian blue or ferric ferrocyanide. Iron(II) sulfate also is used as a reducing agent and an analytical reagent (in brown ring test for nitrate).
Uses
Ferrous sulfate (FeSO4) is also known as iron sulfate or iron vitriol. It is used in the production
of various chemicals, such as sulfur dioxide and sulfuric acid.
Uses
Ferrous Sulfate is a nutrient and dietary supplement that is a source
of iron. it is a white to grayish odorless powder. ferrous sulfate hep-
tahydrate contains approximately 20% iron, while ferrous sulfate
dried contains approximately 32% iron. it dissolves slowly in water
and has high bioavailability. it can cause discoloration and rancidity.
it is used for fortification of baking mixes. in the encapsulated form
it does not react with lipids in cereal flours. it is used in infant foods,
cereals, and pasta products.
Production Methods
Iron(II) sulfate in industrial scale is mostly produced in the pickling process as a by-product of the steel industry. It is obtained when the surface of steel is cleaned with dilute sulfuric acid to remove metal impurities. In the laboratory iron(II) sulfate heptahydrate may be prepared by dissolving iron in dilute sulfuric acid in a reducing atmosphere, followed by crystallization:
Fe + H
2SO
4 → FeSO
4 + H
2 Alcohol may be added to the aqueous solution to speed up crystallization; iron(II) may otherwise oxidize to iron(III) during a slow crystallization process.
Iron(II) oxide or carbonate may be used instead of iron metal to prepare the heptahydrate.
Definition
Copperas: an off-whitesolid, FeSO
4.H
2O; monoclinic; r.d.2.970. There is also a heptahydrate,FeSO
4.7H
2O; blue-green monoclinic;r.d. 1.898; m.p. 64°C. The heptahydrateis the best known iron(II) saltand is sometimes called green vitriolor copperas. It is obtained by the actionof dilute sulphuric acid on ironin a reducing atmosphere. The anhydrouscompound is very hygroscopic.It decomposes at red heat to giveiron(III) oxide, sulphur trioxide, andsulphur dioxide. A solution of iron(II)sulphate is gradually oxidized on exposureto air, a basic iron(III) sulphatebeing deposited.
Definition
A rusty-brown solid prepared by the action
of heat on iron(III) hydroxide or iron(II)
sulfate. It occurs in nature as the mineral
hematite. Industrially it is obtained by
roasting iron pyrites. Iron(III) oxide dissolves
in dilute acids to produce solutions
of iron(III) salts. It is stable at red heat, decomposes
around 1300°C to give triiron
tetroxide, and can be reduced to iron by
hydrogen at 1000°C. Iron(III) oxide is not
ionic in character but has a structure similar
to that of aluminum(III) oxide.
Hazard
Ingestion causes intestinal disorders.
Flammability and Explosibility
Non flammable
Agricultural Uses
Copperas, also called green vitriol, is ferrous sulphate heptahydrate. It is an iron salt fertilizer, which is most effective in overcoming iron deficiency.
Agricultural Uses
Ferrous sulphate heptahydrate (FeSO
4.7H
2O), also called green vitriol or copperas, is a blue-green water-soluble crystal and is the best known ferrous salt. It is obtained by the action of dilute sulphuric acid on iron in a reducing atmosphere. The anhydrous compound is very hygroscopic. It gets oxidized gradually in an aqueous solution. On heating, the solid decomposes to give red ferric oxide, sulphur trioxide (SO
3) and sulphur dioxide (SO
2).
Mechanism of action
Selective, causes a pH shift inside the moss causing enzymes production to cease thus killing the plants
Clinical Use
Iron deficiency anaemia
Safety Profile
A human poison by
ingestion. Moderately toxic to humans by an
unspecified route. An experimental poison
by ingestion, intraduodenal, intraperitoneal,
intravenous, and subcutaneous routes.
Human systemic effects by ingestion:
aggression, somnolence, brain recorlng
changes, diarrhea, nausea or vomiting,
bleedmg from the stomach, coma.
Questionable carcinogen with experimental
tumorigenic data. Experimental teratogenic
and reproductive effects. Mutation data
reported. Potentially explosive reaction with
methyl isocyanoacetate at 25'. May igmte on
contact with arsenic trioxide + sodium
nitrate. When heated to decomposition it
emits toxic fumes of SOx. See also IRON COMPOUNDS.
Potential Exposure
It is used as a fertilizer, food or feed
additive; and in herbicides; process engraving; dyeing, and
water treatment. A byproduct of various chemical and
metal treating operations.
Veterinary Drugs and Treatments
While iron is a necessary trace element in all hemoglobin-utilizing
animals, the use of therapeutic dosages of ferrous sulfate (or other
oral iron) preparations in veterinary medicine is limited primarily
to the treatment of iron-deficiency anemias in dogs (usually due to
chronic blood loss), and as adjunctive therapy in cats when receiving
epoetin (erythropoietin) therapy. Injectable iron products are
usually used in the treatment of iron deficiency anemias associated
with newborn animals.
Drug interactions
Potentially hazardous interactions with other drugs
Antibacterials: reduced absorption of 4-quinolones
and tetracyclines.
Dimercaprol: avoid concomitant use.
Mycophenolate: may significantly reduce absorption
of mycophenolate.
First aid
If this chemical gets into the eyes, remove anycontact lenses at once and irrigate immediately for at least15 min, occasionally lifting upper and lower lids. Seek medical attention immediately. If this chemical contacts theskin, remove contaminated clothing and wash immediatelywith soap and water. Seek medical attention immediately. Ifthis chemical has been inhaled, remove from exposure,begin rescue breathing (using universal precautions, including resuscitation mask) if breathing has stopped and CPR ifheart action has stopped. Transfer promptly to a medicalfacility. When this chemical has been swallowed, get medical attention. Give large quantities of water and inducevomiting. Do not make an unconscious person vomit.Note to physician: Gastric lavage with large amounts of 5%sodium phosphate or water. Follow this with a large amountof 1% sodium bicarbonate over a 3-h period.Note to physician: For severe poisoning do not use BAL[British Anti-Lewisite, dimercaprol, dithiopropanol(C3H8OS2)] as it is contraindicated or ineffective in poisoning from iron.
Metabolism
Following absorption, the majority of iron is bound to
transferrin and transported to the bone marrow where
it is incorporated into haemoglobin. The remainder is
stored within ferritin or haemosiderin or is incorporated
into myoglobin with smaller amounts occurring in haemcontaining enzymes or in plasma bound to transferrin. Only very small amounts are excreted as the body
reabsorbs the iron after the haemoglobin has broken
down
storage
Color Code—Green: General storage may beused. Prior to working with this chemical you should betrained on its proper handling and storage. Store in tightlyclosed containers in a cool, well-ventilated area away fromalkalis.
Incompatibilities
Aqueous solution is acidic. Contact with
alkalies form iron. Keep away from alkalies, soluble carbo nates; gold and silver salts; lead acetate; lime water, potassium
iodide; potassium and sodium tartrate; sodium borate; tannin.
