Magnesium sulfate

From Wikipedia, the free encyclopedia - View original article

Magnesium sulfate

Anhydrous magnesium sulfate

Epsomite (heptahydrate)
Identifiers
CAS number7487-88-9 YesY, 14168-73-1 (monohydrate), 24378-31-2 (tetrahydrate), 15553-21-6 (pentahydrate), 13778-97-7 (hexahydrate), 10034-99-8 (heptahydrate)
PubChem24083
ChemSpider22515 YesY
UNIIML30MJ2U7I YesY
DrugBankDB00653
ChEBICHEBI:32599 YesY
ChEMBLCHEMBL1200456 N
RTECS numberOM4500000
ATC codeA06AD04,A12CC02 B05XA05 D11AX05 V04CC02
Jmol-3D imagesImage 1
Properties
Molecular formulaMgSO4
Molar mass120.366 g/mol (anhydrous)
246.47 g/mol (heptahydrate)
Appearancewhite crystalline solid
Odorodorless
Density2.66 g/cm3 (anhydrous)
2.445 g/cm3 (monohydrate)
1.68 g/cm3 (heptahydrate)
1.512 g/cm3 (11-hydrate)
Melting pointanhydrous decomposes at 1124 °C
monohydrate decomposes at 200 °C
heptahydrate decomposes at 150 °C
undecahydrate decomposes at 2 °C
Solubility in wateranhydrous
26.9 g/100 mL (0 °C)
25.5 g/100 mL (20 °C)
heptahydrate
71 g/100 mL (20 °C)
Solubility1.16 g/100 mL (18 °C, ether)
slightly soluble in alcohol, glycerol
insoluble in acetone
Refractive index (nD)1.523 (monohydrate)
1.433 (heptahydrate)
Structure
Crystal structuremonoclinic (hydrate)
Hazards
MSDSExternal MSDS
EU IndexNot listed
NFPA 704
NFPA 704.svg
0
1
0
Related compounds
Other cationsBeryllium sulfate
Calcium sulfate
Strontium sulfate
Barium sulfate
 N (verify) (what is: YesY/N?)
Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
Infobox references
 
Jump to: navigation, search
Magnesium sulfate

Anhydrous magnesium sulfate

Epsomite (heptahydrate)
Identifiers
CAS number7487-88-9 YesY, 14168-73-1 (monohydrate), 24378-31-2 (tetrahydrate), 15553-21-6 (pentahydrate), 13778-97-7 (hexahydrate), 10034-99-8 (heptahydrate)
PubChem24083
ChemSpider22515 YesY
UNIIML30MJ2U7I YesY
DrugBankDB00653
ChEBICHEBI:32599 YesY
ChEMBLCHEMBL1200456 N
RTECS numberOM4500000
ATC codeA06AD04,A12CC02 B05XA05 D11AX05 V04CC02
Jmol-3D imagesImage 1
Properties
Molecular formulaMgSO4
Molar mass120.366 g/mol (anhydrous)
246.47 g/mol (heptahydrate)
Appearancewhite crystalline solid
Odorodorless
Density2.66 g/cm3 (anhydrous)
2.445 g/cm3 (monohydrate)
1.68 g/cm3 (heptahydrate)
1.512 g/cm3 (11-hydrate)
Melting pointanhydrous decomposes at 1124 °C
monohydrate decomposes at 200 °C
heptahydrate decomposes at 150 °C
undecahydrate decomposes at 2 °C
Solubility in wateranhydrous
26.9 g/100 mL (0 °C)
25.5 g/100 mL (20 °C)
heptahydrate
71 g/100 mL (20 °C)
Solubility1.16 g/100 mL (18 °C, ether)
slightly soluble in alcohol, glycerol
insoluble in acetone
Refractive index (nD)1.523 (monohydrate)
1.433 (heptahydrate)
Structure
Crystal structuremonoclinic (hydrate)
Hazards
MSDSExternal MSDS
EU IndexNot listed
NFPA 704
NFPA 704.svg
0
1
0
Related compounds
Other cationsBeryllium sulfate
Calcium sulfate
Strontium sulfate
Barium sulfate
 N (verify) (what is: YesY/N?)
Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
Infobox references

Magnesium sulfate (or magnesium sulphate) is an inorganic salt (chemical compound) containing magnesium, sulfur and oxygen, with the formula MgSO4. It is often encountered as the heptahydrate sulfate mineral epsomite (MgSO4·7H2O), commonly called Epsom salt, taking its name 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 non-porous London clay. Epsom salt occurs naturally as a pure mineral. Another hydrate form is kieserite.

Anhydrous magnesium sulfate is used as a drying agent. The anhydrous form is hygroscopic (readily absorbs water from the air) and is therefore difficult to weigh accurately; the hydrate is often preferred when preparing solutions (for example, in medical preparations). Epsom salt has been traditionally used as a component of bath salts. Epsom salt can also be used as a beauty product. Athletes use it to soothe sore muscles, while gardeners use it to improve crops. It has a variety of other uses.[1]

Uses[edit]

Medical[edit]

Magnesium sulfate is a common pharmaceutical preparation of magnesium, commonly known as Epsom salts, used both externally and internally. Epsom salts are used as bath salts. The sulfate is supplied in a gel preparation for topical application in treating aches and pains.[citation needed] Oral magnesium sulfate is commonly used as a saline laxative or osmotic purgative. Magnesium sulfate is the main preparation of intravenous magnesium.

Bathing in a 1% solution of Epsom salts (about 500g of Epsom salts for a standard size bathtub of 60 litres) is a "a safe and easy way to increase sulfate and magnesium levels in the body". [2]

Indications for internal use are:

An overdose of magnesium causes hypermagnesemia.

Agriculture[edit]

In gardening and other agriculture, magnesium sulfate is used to correct a magnesium or sulfur deficiency in soil; magnesium is an essential element in the chlorophyll molecule, and sulfur is another important Macronutrient.[16] It is most commonly applied to potted plants, or to magnesium-hungry crops, such as potatoes, roses, tomatoes, lemon trees and peppers 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 neutral, as compared to 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.[citation needed]

Other[edit]

Anhydrous magnesium sulfate is commonly used as a desiccant in organic synthesis due to its affinity for water. During work-up, an organic phase is saturated with magnesium sulfate until it no longer forms clumps. The hydrated solid is then removed with filtration or decantation. Other inorganic sulfate salts such as sodium sulfate and calcium sulfate may also be used in the same way.

Magnesium sulfate is used in bath salts, particularly in flotation therapy where high concentrations raise the bath water's specific gravity, effectively making the body more buoyant. Traditionally, it is also used to prepare foot baths, intended to soothe sore feet. The reason for the inclusion of the salt is partially cosmetic: the increase in ionic strength prevents some of the temporary skin wrinkling (partial maceration) which is caused by prolonged immersion of extremities in pure water. However, magnesium sulfate can also be absorbed into the skin, reducing inflammation.[17] It is naturally present in some mineral waters.[citation needed]

It may also be used as a coagulant for making tofu.[18]

Magnesium sulfate heptahydrate is also used to maintain the magnesium concentration in marine aquaria which contain large amounts of stony corals as it is slowly depleted in their calcification process. In a magnesium-deficient marine aquarium calcium and alkalinity concentrations are very difficult to control because not enough magnesium is present to stabilize these ions in the saltwater and prevent their spontaneous precipitation into calcium carbonate.[19]

Magnesium sulfate is used as the electrolyte to prepare copper sulfate. A magnesium sulfate solution is electrolyzed with a copper anode to form copper sulfate, magnesium hydroxide, and hydrogen:

Cu + MgSO4 + 2 H2O → H2 + CuSO4 + Mg(OH)2.[citation needed]

Magnesium sulfate is used as a brewing salt in beer production to adjust the ion content of the brewing water and enhance enzyme action in the mash or promote a desired flavor profile in the beer.

Physical properties[edit]

Magnesium sulfate is highly soluble in water. The anhydrous form is strongly hygroscopic, and can be used as a desiccant.

Magnesium sulfate is the primary substance that causes the absorption of sound in seawater[20] (acoustic energy is converted to thermal energy). Absorption is strongly dependent on frequency: lower frequencies are less absorbed by the salt, so that the sound travels much farther in the ocean. Boric acid also contributes to absorption, but the most abundant salt in seawater, sodium chloride, has negligible sound absorption.

Hydrates[edit]

Almost all known mineralogical forms of MgSO4 occur as hydrates. Epsomite is the natural analogue of "Epsom salt". Another heptahydrate, the copper-containing mineral alpersite (Mg,Cu)SO4·7H2O,[21] was recently recognized. Both are, however, not the highest known hydrates of MgSO4, due to the recent terrestrial find of meridianiite, MgSO4·11H2O, which is thought to also occur on Mars. Hexahydrite is the next lower (6) hydrate. Three next lower hydrates — pentahydrite (5), starkeyite (4) and especially sanderite (2) — are more rarely found. Kieserite is a monohydrate and is common among evaporitic deposits. Anhydrous magnesium sulfate was reported from some burning coal dumps but never treated as a mineral.

The pH of hydrates is average 6.0 (5.5 to 6.5). Magnesium hydrates have, like copper(II) sulfate, coordinated water.[22]

Manufacturing[edit]

The heptahydrate can be prepared by neutralizing sulfuric acid with magnesium carbonate or oxide, but it is usually obtained directly from natural sources.

Anhydrous magnesium sulfate is prepared only by the dehydration of a hydrate.

Occurrence[edit]

Magnesium sulfates are common minerals in geological environments. Their occurrence is mostly connected with supergene processes. Some of them are also important constituents of evaporitic potassium-magnesium (K-Mg) salts deposits.

References[edit]

  1. ^ "Quick Cures/Quack Cures: Is Epsom Worth Its Salt?". Wall Street Journal. April 9, 2012. 
  2. ^ "Report on Absorption of magnesium sulfate (Epsom salts) across the skin". Retrieved 2013-09-06. 
  3. ^ "Pharmaceutical Information – Magnesium Sulfate". RxMed. Retrieved 2009-07-06. 
  4. ^ "When clicking citation, it is listed under ''Other medicinal and home uses''". Disabled-world.com. 2007-01-04. Retrieved 2009-07-06. 
  5. ^ a b Blitz M, Blitz S, Hughes R, Diner B, Beasley R, Knopp J, Rowe BH. Aerosolized magnesium sulfate for acute asthma: a systematic review. Chest 2005;128:337-44. PMID 16002955.
  6. ^ jab averts pregnancy danger', BBC News, 30 May 2002
  7. ^ "Magnesium sulfate for preterm labor". Webmd.com. 2007-01-19. Retrieved 2009-07-06. 
  8. ^ Lewis DF (September 2005). "Magnesium sulfate: the first-line tocolytic". Obstet. Gynecol. Clin. North Am. 32 (3): 485–500. doi:10.1016/j.ogc.2005.03.002. PMID 16125045. 
  9. ^ Simhan HN, Caritis SN (2007). "Prevention of Preterm Delivery". New England Journal of Medicine 357 (5): 477–487. doi:10.1056/NEJMra050435. PMID 17671256. 
  10. ^ Nanda, K; Grimes, DA (2006). "Magnesium sulfate tocolysis: Time to quit". Obstetrics and Gynecology 108 (4): 986–989. doi:10.1097/01.AOG.0000236445.18265.93. PMID 17012463. 
  11. ^ FDA http://www.fda.gov/Safety/MedWatch/SafetyInformation/SafetyAlertsforHumanMedicalProducts/ucm354603.htm |url= missing title (help). Retrieved 2 June 2013. 
  12. ^ "Epsom salt can prevent cerebral palsy: U.S. study". Reuters.com. 2008-01-31. Retrieved 2009-07-06. 
  13. ^ Doyle, L. W.; Crowther, C. A.; Middleton, P.; Marret, S. (2009). "Antenatal magnesium sulfate and neurologic outcome in preterm infants: A systematic review". Obstetrics and gynecology 113 (6): 1327–1333. doi:10.1097/AOG.0b013e3181a60495. PMID 19461430.  edit
  14. ^ Corkeron M (2003). "Magnesium infusion to treat Irukandji syndrome". Med J Aust 178 (8): 411. PMID 12697017. 
  15. ^ "BARIUM CHLORIDE DIHYDRATE 4. First Aid Measures". Jtbaker.com. Retrieved 2009-07-06. 
  16. ^ Reece, J. B., & Campbell, N. A. (2011). Campbell biology. (9th ed., p. 791). Boston: Benjamin Cummings
  17. ^ "How do epsom salts reduce swelling?". Retrieved 2013-02-09. 
  18. ^ "Process for producing packed tofu". 
  19. ^ "Do-It-Yourself Magnesium Supplements for the Reef Aquarium". Reefkeeping. 2006. Retrieved 2008-03-14. 
  20. ^ "Underlying physics and mechanisms for the absorption of sound in seawater". Resource.npl.co.uk. Retrieved 2009-07-06. 
  21. ^ Peterson, Ronald C.; Hammarstrom, Jane M.; Seal, II, Robert R (Feb 2006). "Alpersite (Mg,Cu)SO4·7H2O, a new mineral of the melanterite group, and cuprian pentahydrite: Their occurrence within mine waste". American Mineralogist 91 (2–3): 261–269. doi:10.2138/am.2006.1911. 
  22. ^ Lucia Odochian "Study of the nature of the crystallization water in some magnesium hydrates by thermal methods," J. of Thermal Analysis and Calorimetry, Volume 45, Number 6, December, 1995. doi:10.1007/BF02547437

External links[edit]