Magnesium sulfate
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| Magnesium sulfate | |
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| General | |
| Systematic name | Magnesium sulfate (anhydrous); Magnesium sulfate heptahydrate |
| Other names | Epsom salts bitter salts |
| Molecular formula | MgSO4 (anhydrous) MgSO4·7H2O |
| Formula weight | 120.36 g/mol (anhydrous) 246.48 g/mol (Heptahydrate) |
| Appearance | white crystalline solid |
| CAS number | 7487-88-9(anhydrous) 10034-99-8(heptahydrate) |
| EINECS number | ? |
| Properties | |
| Density and phase | ? g/cm3, solid |
| Solubility in water | 25.5 g/100 ml (20 °C) |
| In ethanol | Slightly soluble (anh.) Insoluble (hydrate) |
| Melting point | 1124°C decomp. |
| Dehydration Temperature | 250°C |
| Structure | |
| Coordination geometry | ? |
| Crystal structure | monoclinic (hydrate) |
| Safety data | |
| PEL-TWA (OSHA) | — |
| RTECS number | ? |
| Supplementary data page | |
| Structure & properties | n, εr, etc. |
| Thermodynamic data | Phase behaviour Solid, liquid, gas |
| Spectral data | UV, IR, NMR, MS |
| Related compounds | |
| Other cations | Calcium sulfate Aluminium sulfate |
| Related compounds | |
| Except where noted otherwise, data are given for materials in their standard state (at 25°C, 100 kPa) Infobox disclaimer and references |
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Magnesium sulfate is a chemical compound containing magnesium, with the formula MgSO4. It is often encountered as the heptahydrate, MgSO4·7H2O, commonly called Epsom salt. Anhydrous magnesium sulfate is used as a drying agent. Since the anhydrous form is deliquescent and therefore harder to weigh accurately, the hydrate is often preferred when preparing solutions, for example in medical preparations. Epsom salts have traditionally been used as a component of bath salts.
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[edit] Origin
In 1618 a farmer at Epsom in England attempted to give his cows water, but they refused to drink it to due its sour/bitter taste. However the farmer noticed that the water seemed to heal scratches and rashes. The fame of Epsom salts now began to spread.
Epsom salt was originally prepared by boiling down mineral waters at Epsom, England, and afterwards prepared from sea water. In more recent times, these salts are obtained from certain minerals such as epsomite.
[edit] Agricultural use
In agriculture and gardening, magnesium sulfate is used to correct magnesium deficiency in soil (magnesium is an essential element in the chlorophyll molecule). It is most commonly applied to potted plants, or to magnesium-hungry crops, such as potatoes, roses, and tomatoes. The advantage of magnesium sulfate over other magnesium soil amendments (such as dolomitic lime) is its high solubility.
[edit] Medical use
Locally it may be used as a treatment of an ingrown nail. Oral magnesium sulfate, or magnesium hydroxide, is used as a laxative. Epsom salts are also available in a gel form for topical application in treating aches and pains. Intravenous use is broadening, as magnesium sulfate reduces striated muscle contractions and blocks peripheral neuromuscular transmission by reducing acetylcholine release at the myoneural junction, as well as other effects. Indications for its use are:
- Hypomagnesemia (low magnesium concentrations in the blood)
- Treatment (and sometimes prevention) of seizures in eclampsia, for which it is the most effective therapy.
- In some cardiac arrhythmias, most notably in:
- Severe refractory ventricular fibrillation ("V-fib"), Pulseless ventricular tachycardia ("V-tach"), atrial fibrillation, and Torsades de pointes tachycardia
- As a bronchodilator after beta-agonist and anticholinergic agents have been tried, e.g. in severe exacerbations of asthma.[1] In fact, recent studies have revealed that magnesium sulfate can be nebulized to reduce the symptoms of acute asthma (Blitz et al 2005). In the UK, it is commonly administered via the intravenous route for the management of severe asthma attacks
- As a tocolytic agent, administered intravenously for the treatment of preterm labor: Until recently, intravenous magnesium sulfate was used extensively as first-line therapy in pregnancy to treat or forestall preterm contractions and preterm labor, but studies have shown that presumption of its effectiveness was unwarranted. Other, better tocolytic agents are now commonly used.
- For treatment of acute migraine.
- In the treatment of tetanus
- In the management of phaeochromocytoma
- Can also be used in the treatment of acne, when applied as a liquid to problematic areas.[citation needed]
- Recent (2004) research at the School of Biosciences, Birmingham University, UK has shown that both magnesium and sulphate are absorbed through the skin when bathing in 1% solution.
[edit] Use in organic chemistry
Anhydrous magnesium sulfate is commonly used as a desiccant in organic synthesis due to its affinity for water. During workup, an organic phase is saturated with magnesium sulfate until it no longer forms clumps. The hydrated solid is then removed with filtration or decantation.
A number of other inorganic sulfate salts, sodium sulfate and calcium sulfate for example, may also be used in the same way.
[edit] Other uses
Magnesium sulfate is used as in bath salts, particularly in floatation therapy where high concentrations raise the bath water's specific gravity, effectively making the body more buoyant. This property is also used to restore some Lava lamps damaged by being shaken by exchanging the water and adding drops of a concentrated solution until sustainable buoyancy is reached. Traditionally, it is also used to prepare foot baths, intended to soothe sore feet. The reason for the inclusion of the salt is cosmetic: the increase in ionic strength prevents some of the temporary skin wrinkling ("pruning") which is caused by prolonged immersion of extremities in pure water. Magnesium sulfate paste has been used as an agent for drawing (dehydrating) boils and carbuncles. In some parts of the world (such as New Zealand), it is added to homemade drinks, such as lemon cordials. Here the sulfate part of the salt is not important, rather it is the intensely sour taste of magnesium ion Mg2+ which acts as flavoring agent.
Also recommended for dropsy treatment for fishes.[citation needed]
[edit] See also
[edit] Reference
- ^ 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.
