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Epsom salts, chemically known as magnesium sulfate heptahydrate (MgSO₄·7H₂O), are a naturally occurring mineral compound composed of magnesium, sulfur, and oxygen, and they appear as colorless, crystalline granules that are highly soluble in water.
Epsom salts is difficult to dissolve and thus being easier to weigh than anhydrous magnesium sulphate for being convenient for quantitative control in industry.
Epsom salts or magnesium sulphate is a chemical compound, a salt with the formula MgSO4, consisting of magnesium cations Mg2+ (20.19% by mass) and sulfate anions SO2−4.
CAS Number: 10034-99-8
Molecular Formula: Mg.O4S.7H2O
Molecular Weight: 246.47
EINECS Number: 600-073-4
Synonyms: Magnesium sulfate heptahydrate, Epsom salt, magnesium sulphate heptahydrate, Magnesia sulphurica, Magnesium sulfate (1:1) heptahydrate, MgSO4.7H2O, Epsom salt(heptahydrate), Bitter salt, MgSO4*7H2O, SK47B8698T, Magnesii sulfatis heptahydras, sulfuric acid magnesium salt heptahydrate, CHEBI:31795, magnesium sulfate--water (1/7), E-518(MAGNESIUM SULFATE HEPTAHYDRATE), MAGNESIUM SULPHATE (1:1) HEPTAHYDRATE, INS-518(MAGNESIUM SULFATE HEPTAHYDRATE), INS NO.518(MAGNESIUM SULFATE HEPTAHYDRATE), MAGNESIUM SULFATE HEPTAHYDRATE (EP IMPURITY), MAGNESIUM SULFATE HEPTAHYDRATE (EP MONOGRAPH), MAGNESIUM SULFATE HEPTAHYDRATE [EP IMPURITY], MAGNESIUM SULFATE HEPTAHYDRATE [EP MONOGRAPH], MAGNESIUM SULFATE HEPTAHYDRATE (USP MONOGRAPH), MAGNESIUM SULFATE HEPTAHYDRATE [USP MONOGRAPH], MgSO4(H2O)7, 10034-99-8, magnesium, sulfate, heptahydrate, Sulfuric acid, magnesium salt, hydrate (1:1:7), MFCD00149785, Sulfuric acid magnesium salt (1:1), heptahydrate, Epsomite, Magnesium sulfate [USAN:JAN], Bittersalz, Epsomite (Mg(SO4).7H20), Magnesium sulfate heptahydrate (MgSO4.7H2O), MAGNESIUMSULFATEHEPTAHYDRATE, Sulfuric acid, magnesium salt (1:1), heptahydrate, Conclyte-Mg (TN), Magnesium sulfate (USP), MAGNESIUM(II), SULFATE, HEPTAHYDRATE, SCHEMBL840, Magnesium sufate heptahydrate, EPSOM SALT [WHO-IP], CHEMBL3989857, DTXSID5040544, MAGNESIA SULPHURICA [HPUS], Magnesium sulfate hydrate (JP17), AKOS015903838, FM39296, MAGNESIUM SULFATE HYDRATE [JAN], Magnesium sulfate heptahydrate ACS grade, 14457-55-7, MAGNESIUM SULFATE HEPTAHYDRATE [MI], DB-297725, NS00076332, D01108, MAGNESIUM SULFATE HEPTAHYDRATE [WHO-DD], MAGNESII SULFATIS HEPTAHYDRAS [WHO-IP LATIN], Magnesium sulfate heptahydrate, Cell Culture Reagent, Q15628528, Magnesium sulfate heptahydrate, meets the specifications of Ph. Eur., USP, BP, MAGNESIUM SULFATE 7HYD XTL, MAGNESIUMSULFATE,HEPTAHYDRATE,BIOTECHG, Magnesium sulfate heptahydrate Manufacturer, MAGNESIUM SULFATE, HEPTAHYDRATE, BIO-REFINEDMAGNESIUM SULFATE, HEPTAHYDRATE, BIO-REFINEDMAGNESIUM SULFATE, HEPTAHYDRATE, BIO-REFINEDMAGNESIUM SULFATE, HEPTAHYDRATE, BIO-REFINED, MAGNESIUM SULFATE, HEPTAHYDRATE, REAGENT (ACS)MAGNESIUM SULFATE, HEPTAHYDRATE, REAGENT (ACS)MAGNESIUM SULFATE, HEPTAHYDRATE, REAGENT (ACS), Crystalline magnesium sulfate, MgSO, MAG-BIND EQUIPURE LIBR
Epsom salts appears as white or colorless needle-like or inclined columnar crystal, being odorless, cool and slightly bitter with a molecular weight of 246.47, specific gravity 1.68, being easily soluble in water and slightly soluble in ethanol and glycerol.
Epsom salts is soluble in its own crystal water.
Epsom salts can be subject to thermal decomposition with loss of four molecules of crystal water molecules at 70, 80 °C.
Epsom salts will lose all the crystalline water at 200 °C to become anhydrous product.
In the air (dry), Epsom salts is easy to be weathered into powder with heating gradually removing the crystal water molecules to become anhydrous magnesium sulfate.
Epsom salts does not contain any toxic impurities.
Epsom salts is mainly used for the manufacture of fertilizer, tanning, printing and dyeing, catalyst, papermaking, plastic, porcelain, pigments, matches, explosives and fireproof materials.
Epsom salts can be used for printing fine cotton, silk, as the weighting agent of cotton yarn and the filler of kapok products; as Epsom salt of medicine.
Epsom salts is named after the town of Epsom in Surrey, England, where the compound was first discovered in the mineral waters of local springs during the 17th century, and it quickly became popular for its reputed healing and therapeutic properties.
Epsom salts is a white crystalline solid, soluble in water but not in ethanol.
Epsom salts is usually encountered in the form of a hydrate MgSO4·nH2O, for various values of n between 1 and 11.
The most common is the heptahydrate MgSO4·7H2O, known as Epsom salt, which is a household chemical with many traditional uses, including bath salts.
The main use of Epsom salts is in agriculture, to correct soils deficient in magnesium (an essential plant nutrient because of the role of magnesium in chlorophyll and photosynthesis).
The monohydrate is favored for this use; by the mid 1970s, its production was 2.3 million tons per year.
The anhydrous form and several hydrates occur in nature as minerals, and the salt is a significant component of the water from some springs.
Epsom salts is usually obtained directly from dry lake beds and other natural sources.
Epsom salts can also be prepared by reacting magnesite (magnesium carbonate, MgCO3) or magnesia (oxide, MgO) with sulfuric acid (H2SO4): H2SO4 + MgCO3 → MgSO4 + H2O + CO2
Another possible method is to treat seawater or magnesium-containing industrial wastes so as to precipitate magnesium hydroxide and react the precipitate with sulfuric acid.
Also, Epsom salts is manufactured by dissolution of magnesium sulfate monohydrate (kieserite, MgSO4·H2O) in water and subsequent crystallization of the heptahydrate.
Epsom salts relaxation is the primary mechanism that causes the absorption of sound in seawater at frequencies above 10 kHz (acoustic energy is converted to thermal energy).
Lower frequencies are less absorbed by the salt, so that low frequency sound travels farther in the ocean.
Boric acid and magnesium carbonate also contribute to absorption.
Melting point: 1124 °C
Density: 2.66
Bulk density: 900 kg/m³
Vapor density: <0.01 (vs air)
Vapor pressure: <0.1 mm Hg (20 °C)
Refractive index: 1.433
Storage temp.: Store at +5 °C to +30 °C
Solubility: H₂O: 1 M at 20 °C, clear, colorless
Form: Solid
Specific gravity: 1.68
Color: White
pH: 5.0–8.0 (25 °C, 50 mg/mL in H₂O)
Odor: Odorless
Water solubility: Soluble in water and acid. Slightly soluble in alcohol and glycerol.
λmax: λ: 260 nm Amax: 0.010; λ: 280 nm Amax: 0.010
Merck: 14,5691
Dielectric constant: 8.2 (Ambient)
Stability: Stable. Non-flammable. May slowly deteriorate in contact with air.
InChIKey: WRUGWIBCXHJTDG-UHFFFAOYSA-L
LogP: –1.031 (est)
Epsom salts are widely used in a variety of health, wellness, and industrial applications due to their ability to release magnesium and sulfate ions when dissolved in water—these ions are readily absorbed through the skin, which is why Epsom salt baths are commonly used to relieve muscle aches, reduce inflammation, and promote relaxation.
In medical contexts, Epsom salts may be taken orally as a laxative to relieve occasional constipation, as magnesium sulfate acts osmotically in the intestines, drawing water into the bowel to stimulate movement.
Additionally, in emergency or hospital settings, magnesium sulfate can be administered intravenously to treat magnesium deficiencies, eclampsia, or certain types of arrhythmias.
Beyond personal care, Epsom salts are frequently used in gardening and agriculture, where they serve as a magnesium-rich fertilizer that supports chlorophyll production and overall plant growth, especially in crops like tomatoes, peppers, and roses that may show signs of magnesium deficiency.
In the industrial sector, Epsom salts are employed in processes such as textile dyeing, tanning, water treatment, and even in food preparation, where magnesium sulfate may be used as a firming agent or a nutrient supplement under the food additive code E518.
Epsom salts can be taken as an internally administrated laxative.
As a result of slow absorption and rapid discharge, it generally does not show toxic effects. Oral administration of large doses can cause nerve, muscle paralysis, heart failure, sometimes can cause skin diseases.
Industrial Epsom salts generally refers to heptahydrate, appearing as colorless needle-like or inclined columnar crystal, being odorless and of bitter taste.
Epsom salts is easily soluble in water and slightly soluble in ethanol and glycerol.
In addition to its use in foods as a flavor enhancer, nutrient supplement and processing aid, magnesium sulfate (as Epsom salt) is employed in over-the-counter preparations as a laxative.
As a legend (prescription drug) it has been used as an anticonvulsant and electrolyte replenisher.
The heptahydrate takes its common name "Epsom salt" from a bitter saline spring in Epsom in Surrey, England, where the salt was produced from the springs that arise where the porous chalk of the North Downs meets the impervious London clay.
The heptahydrate readily loses one equivalent of water to form the hexahydrate.
It is a natural source of both magnesium and sulphur.
Epsom salts are commonly used in bath salts, exfoliants, muscle relaxers and pain relievers.
However, these are different from Epsom salts that are used for gardening, as they may contain aromas and perfumes not suitable for plants.
Epsom salts, or kieserite, can be prepared by heating the heptahydrate to 120 °C.
Further heating to 250 °C gives anhydrous magnesium sulfate.
Kieserite exhibits monoclinic symmetry at pressures lower than 2.7 GPa after which it transforms to phase of triclinic symmetry.
Production method Of Epsom salts:
Sulfuric acid method: this method takes dolomite, serpentine and magnesite as raw material.
Add water or mother liquor to the neutralization reactor, and then add the mixture of sulfuric acid and the bitter earth powder containing more than 85 percent of magnesium oxide in a certain proportion to the reactor for carrying out neutralization reaction, control the Ph of 5 with the concentration of 39-40 ° Bé. Stir for 30 min for thorough reaction.
Epsom salts: MgO + H2SO4 + 6H2O → MgSO4 • 7H2O
The neutralization liquid is kept at 80 °C and the filtered filtrate is sent into a crystallizer, and then added with proper seed crystal, and then cooled, filtered and centrifuged.
The obtained filtrate is dried at 50-55 °C to obtain magnesium sulphate.
The mother liquor is returned for ingredient use.
Recrystallization: the bitter brine obtained in the salt lake is subject to natural evaporation to be condensed into crude magnesium (crude magnesium sulfate).
The crude magnesium is taken as raw material, and is dissolved in water at 80-90 °C, then is clarified at 60-70 °C, cooled and crystallized at 20-25 °C, and centrifuged and dried to obtain industrial magnesium sulfate product.
Industrial magnesium sulfate is immersed in distilled water.
The Ph value is adjusted with sulfuric acid.
Epsom salts is subject to centrifugal separation, drying dehydration and further recrystallization, made of magnesium sulfate for medical use.
Sea salt is subject to sunshine to obtain bittern with evaporation obtaining high-temperature salt.
The composition is MgSO4> 30%, NaCI <35%, MgCl2 about 7%, KCl is about 0.5%.
Bittern can be immersed in 200g/L MgCl2 solution at 48 ℃ with NaCl being dissolved less while MgSO4 being dissolved more.
After separation, the immersed liquid was cooled to 10 ° C to precipitate crude MgSO4•7H2O with secondary recrystallization obtaining the finished product.
In the neutralization tank, the magnesia was slowly added into water and mother liquor, then neutralized with sulfuric acid, and the color changed from soil color to red.
Control the Ph at 5 with the relative density being 1.37~1.38 (39~40 ° Bé).
The neutralized solution was filtered at 80 °C and then the pH was adjusted to 4 with sulfuric acid. Appropriate seed crystals were added and the crystals were cooled to 30 °C.
After separation, the product is dried at 50 to 55 °C, and the mother liquor is returned to the neutralization tank.
We can also use low concentration of sulfuric acid for neutralization with bitter soil containing 65% of magnesium oxide content.
Undergo filtration, precipitation, concentration, crystallization, centrifugal separation, drying and preparation to obtain magnesium sulfate heptahydrate.
MgO + H2SO4 + 6H2O → MgSO4 • 7H2O
Uses Of Epsom salts:
Epsom salts can be used for catharsis with its saturated solution subject to topical administration.
Epsom salts has anti-inflammatory, detumescence, detoxification, analgesic effect, and can inhibit the effect of central nervous system, anti-traction and antispasmodic; used as the weighing agent of printing fine cotton, cotton, silk and the filler for kapok products; it can be used for the manufacturing of grass, fertilizers, porcelain, pigments, matches, explosives and fireproof materials; can be used as the medium component in the microbial industry; supplying the magnesium for brewing additives; used as filler to enhance the thermal resistance in the leather industry; used for the production of fresh yeast, monosodium glutamate and the stabilizer of dicalcium phosphate used in toothpaste production; can also be used in cement coagulant; pulp industry, rayon and silk industry, etc.
Product containing a small amount of crystal water or no crystal water can be used for the synthesis of product that contains low water content and mixed ingredients.
In organic chemical industry, it can be used for desiccant and dehydrating agent for printing thin cotton, silk, as the aggravating agent of cotton and filler of kapok products.
Epsom salts can be used for leather industry, fertilizer, porcelain, matches, explosives, printing and dyeing, pharmaceutical and other industries
Epsom salts can be used for steelmaking and ironmaking
Magnesium sulfate is a feed nutrition enhancer.
Epsom salts can be used as laxative, cholagogue, for cathartic and duodenal diversion
Epsom salts can be used as analysis reagents and mordant
Epsom salts can be used as food fortifier.
China provides that it can be used for dairy products with the usage amount of 3~7 g/kg; usage amount in the beverages and milk beverages is 1.4~2.8g/kg; the maximum dose in mineral drinks should be 0.05g/kg.
Epsom salts can be used as nutritional supplements, curing agents, flavor enhancers, processing aids. Brewing additives for supplement the magnesium of brewing water; as a source of nutrients during fermentation to enhance the fermentation capacity; improve the flavor of synthetic wine (usage amount of 0.002%).
In Europe for the production of "Bolton" type of beer.
It is often used in combination with the calcium salt for the yeast-purpose water.
Epsom salts can be used as tanning filler.
In the printing and dyeing industry, it can be used as the aggravating agent of the thin cotton used as paper sizing agent.
Used as medicine, food, feed additives, fermentation, industry, engineering plastics, agricultural fertilizers, household chemicals, and other fields.
Epsom salts is the core element of chlorophyll, being able to enhance the reduction process of plants and improve the disease resistance.
It is essential for photosynthesis. Magnesium is the activator of many enzymes, can promote carbohydrate metabolism, nucleic acid synthesis, phosphate conversion.
Magnesium sulfate is a very important fertilizer, because it can provide the crop with rich nutrition.
Epsom salts can help crop growth and yield. Sulfur is the main component of proteins and enzymes in plants, which can promote root growth, enhance metabolism and redox in plants, and thus promote the growth of crops and increase the yield.
Epsom salts is a good fertilizer, it can not only provide magnesium and sulfur elements, and can also make the compacted soil be loose and strong, well-developed root system and enable full absorption of nutrients so that plants can become lusher.
Magnesium and other 15 elements are considered to be plant growth and high-yielding nutrients.
The nutritional components and fertilizers of the plants, the nutrients (nitrogen, phosphorus and potassium) contained in traditional fertilizers are clearly insufficient to increase agricultural yields while moderate nutrient (calcium, magnesium and sulfur) and micronutrients (zinc, copper, iron, manganese, boron, molybdenum and chlorine) become less in the soil, and the lack of these nutrients can result in reduced crop yields.
Magnesium has been proven to be an important source of increased productivity and agricultural production, and must be replenished in a timely manner since the excessively extraction of magnesium from the soil is the major source of this widespread disease.
Epsom salts can be mixed with nitrogen, phosphorus and potassium into compound fertilizer or mixed fertilizer according to different needs, and can be mixed with one or more elements into various fertilizers and photosynthetic fertilizers respectively.
After the contrast practical fertilization experiment of treatment of nine crops including rubber trees, fruit trees, tobacco leaves, potatoes and cereals, magnesium-containing compound fertilizer can make the crop grow 15-50% better than magnesium-free fertilizer.
Feed grade Epsom salts heptahydrate can be used as a magnesium supplement in the processing of feed.
Magnesium is an indispensable factor in the process and muscle contraction of livestock and poultry.
Epsom salts is the activator of various enzymes in livestock and poultry, and plays an extremely important role in animal metabolism and nerve function.
If the animal body undergoes magnesium deficiency, it will lead to material metabolism and neurological disorders, supply disorders, affecting the growth and development of livestock and poultry, and even lead to death.
Epsom salts is used as a source of magnesium in foliar application of fertilizers to plants.
Epsom salts is used in preparation of magnesium standard solutions
Epsom salts is a nutrient and dietary supplement.
It is soluble in water and its solutions are neutral.
Epsom salts exists as crystals with a cooling, saline, bitter taste.
Epsom salts is also termed epsom salt.
Epsom salts has been used: as a component in Kreb′s Ringer buffer, as a component in minimal medium to culture Ralstonia solanacearum, in the preparation of maceration solution for Lamb′s lettuce cell isolation and isotonic glucose buffer
Epsom salts, a naturally occurring mineral, has needle-like, orthorhombic crystals.
Epsom salts may be found in the saline efflorescence of the surface of some soils of arid regions.
It is soluble in water, which makes magnesium easily available to plants.
Epsom salts is used as a source of magnesium in many chemical industries like paper, sugar refining, etc.
Epsom salt, MgSO4·7H2O(rhombic), is the commonest hydrate of magnesium sulphate.
Used as a plant nutrient to overcome magnesium deficiency, epsom salt finds application in fertilizer manufacture besides being used in fireproofing cotton and in tanning leather.
Epsom salt is also known to be a laxative.
The main external use is the formulation as bath salts, especially for foot baths to soothe sore feet. Such baths have been claimed to also soothe and hasten recovery from muscle pain, soreness, or injury.
Health effects of magnesium sulfate that have been proposed include resistant depression and as an analgesic for migraine and chronic pain.
Epsom salts has also been studied in the treatment of asthma,[18]preeclampsia, and eclampsia.
Epsom salts is usually the main component of the concentrated salt solution used in isolation tanks to increase its specific gravity to approximately 1.25–1.26.
This high density allows an individual to float effortlessly on the surface of water in the closed tank, eliminating stimulation of as many of the external senses as possible.
In the UK, a medication containing magnesium sulfate and phenol, called "drawing paste", is useful for small boils or localized infections and removing splinters.
Internally, magnesium sulfate may be administered by oral, respiratory, or intravenous routes.
Internal uses include replacement therapy for magnesium deficiency, treatment of acute and severe arrhythmias, as a bronchodilator in the treatment of asthma, preventing eclampsia and cerebral palsy, a tocolytic agent, and as an anticonvulsant.
The effectiveness and safety of magnesium sulfate for treating acute bronchiolitis in children under the age of 2 years old is not well understood.
In agriculture, Epsom salts is used to increase magnesium or sulfur content in soil.
Epsom salts is most commonly applied to potted plants, or to magnesium-hungry crops such as potatoes, tomatoes, carrots, peppers, lemons, and roses.
The advantage of magnesium sulfate over other magnesium soil amendments (such as dolomitic lime) is its high solubility, which also allows the option of foliar feeding.
Solutions of magnesium sulfate are also nearly pH neutral, compared with the slightly alkaline salts of magnesium as found in limestone; therefore, the use of magnesium sulfate as a magnesium source for soil does not significantly change the soil pH.
Contrary to the popular belief that magnesium sulfate is able to control pests and slugs, helps seeds germination, produce more flowers, improve nutrient uptake, and is environmentally friendly, it does none of the purported claims except for correcting magnesium deficiency in soils.
Epsom salts can even pollute water if used in excessive amounts.
Safety Profile Of Epsom salts:
While Epsom salts (magnesium sulfate heptahydrate) are generally considered safe when used appropriately, especially in personal care and medical settings, they can still pose certain hazards or risks under specific conditions, particularly if misused, overused, or improperly handled in industrial contexts.
One of the primary hazards associated with Epsom salts occurs when taken internally in excessive amounts.
Although magnesium sulfate is often used as a laxative, ingesting too much can lead to serious gastrointestinal discomfort, including diarrhea, nausea, cramping, and electrolyte imbalances, especially in individuals with underlying health conditions such as kidney disease.
In more severe cases, excessive magnesium in the body—known as hypermagnesemia—can lead to muscle weakness, low blood pressure, slowed heart rate, difficulty breathing, or even cardiac arrest, particularly if the kidneys are unable to efficiently remove the excess magnesium from the bloodstream.
When administered intravenously in medical settings, magnesium sulfate must be dosed carefully, as incorrect dosage or rapid infusion can result in toxic effects on the central nervous system and cardiovascular system, potentially causing respiratory depression, confusion, loss of reflexes, or arrhythmias.
For this reason, it is typically used under strict medical supervision, especially in hospital settings (e.g., to manage seizures in eclampsia patients).
