Magnesium hydroxide, magnesium hydroxide- an inorganic compound of composition Mg (OH) 2. White crystals that are poorly soluble in water. The compound exhibits weak basic properties.

It is used as a drug to reduce the acidity of gastric juice and as an antidote for arsenic poisoning. Intermediate in the synthesis of metallic magnesium.

Distribution in nature

Minerals that contain magnesium hydroxide are quite rare. Among these minerals, brucite is the most important. In addition to the main compound, Mg (OH) 2, it may contain impurities MnO, FeO, Fe 2 O 3. Brucite is formed as a result of the hydrolysis of natural magnesium compounds soluble in meadows.

Mg (OH) 2 is also found in the mineral hydromagnesite, which in composition is close to a mixture of magnesium hydroxide and carbonate - 4MgCO 3 Mg (OH) 2 2H 2 O.

Physical properties

Magnesium hydroxide are white crystals that are poorly soluble in water and do not conduct electricity. Actively dehumidifies the air by absorbing water and carbon dioxide. It dissolves well in ammonium salts.

Receipt

Given the low prevalence of magnesium hydroxide in mineral deposits, it is mined using a different method. For industrial needs, Mg (OH) 2 is obtained by precipitation of sea water and brines. Hydroxide extraction from sea water was first used in 1865 on the French Mediterranean coast.

In laboratory languages, magnesium hydroxide can be synthesized by burning magnesium metal in water vapor:

Precipitation of poorly soluble hydroxide during the interaction of magnesium salts with alkalis and ammonium hydroxide is also used.

However, precipitation with ammonium hydroxide occurs entirely due to the constant decrease in OH - ions.

Chemical properties

Magnesium hydroxide decomposes when heated above 350 ° C in vacuum and at 800 ° C in air:

The compound is a weak base, interacts with acids, ammonium salts and acid oxides (actively absorbs carbon dioxide from the air):

When heated, it reacts with certain nonmetals, which result in the formation of the corresponding hydrides:

Complex formation with inorganic ligands for Mg 2+ cations is uncharacteristic (unstable complexes with oxygen molecules are known for magnesium halides), therefore Mg (OH) 2 is insoluble in meadows.

Application

Magnesium hydroxide is used as an intermediate in the synthesis of magnesium metal. It is used to purify sugar, water in boiler rooms, and in the production of toothpastes.

In medicine

Magnesium hydroxide is widely used as an antacid for high acidity of gastric juice (gastritis, gastric and duodenal ulcers). Included in the drug "Maalox" (an acronym for "ma manure al Yuminov ox id"), as well as its analogue "almagel", which reduce acidity.

Neutralizing the perchloric acid contained in the stomach turns into magnesium chloride, which has a laxative effect. Used for poisoning with acids and arsenic compounds.

Video on the topic

Related Images

International name:

Dosage form:

Pharmachologic effect:

Indications:

Bartel drugs Prolanta

International name: Algeldrate+Magnesium hydroxide

Dosage form: oral gel, oral suspension, tablets, chewable tablets

Pharmachologic effect: A combined agent, the effect of which is determined by the components included in its composition: it has an antacid, adsorbent, enveloping,...

Indications: Acute gastritis; hyperacid gastritis; acute duodenitis; peptic ulcer of the stomach and duodenum (in the acute phase); symptomatic ulcers...

Vitrum Mag

International name:

Dosage form: chewable tablets

Pharmachologic effect:

Indications:

Gastracid

International name: Algeldrate+Magnesium hydroxide

Dosage form: oral gel, oral suspension, tablets, chewable tablets

Pharmachologic effect: A combined agent, the effect of which is determined by the components included in its composition: it has an antacid, adsorbent, enveloping,...

Indications: Acute gastritis; hyperacid gastritis; acute duodenitis; peptic ulcer of the stomach and duodenum (in the acute phase); symptomatic ulcers...

Gastrik

International name: Calcium carbonate+Magnesium hydroxide

Dosage form: chewable tablets

Pharmachologic effect: An antacid that neutralizes excess free HCl in the stomach, thereby providing a protective effect on the gastric mucosa. Quick...

Indications: Hyperacidity of gastric juice (including after errors in diet, taking drugs and abuse of ethanol, coffee, nicotine: heartburn, feeling of fullness or heaviness in the epigastric region, flatulence, nausea, sour belching).

Liquid antacid "York" with simethicone

International name: Algeldrate+Magnesium hydroxide+Simethicone

Dosage form: oral suspension, oral suspension [cherry], oral suspension [mint]

Pharmachologic effect: A combined agent, the effect of which is determined by the components included in its composition; has an antacid, adsorbent, enveloping...

Indications: Acute gastritis; chronic gastritis with increased and normal secretory function of the stomach (in the acute phase); acute duodenitis; peptic ulcer...

Cardiomagnyl

International name: Acetylsalicylic acid+Magnesium hydroxide

Dosage form: film-coated tablets

Pharmachologic effect: Cardiomagnyl is a combined drug, the action of which is due to its constituent components. ASA - NSAID; blocking COX1 and COX2...

Indications: Pain syndrome of low intensity; febrile syndrome.

Coalgel

International name: Algeldrate+Magnesium hydroxide

Dosage form: oral gel, oral suspension, tablets, chewable tablets

Pharmachologic effect: A combined agent, the effect of which is determined by the components included in its composition: it has an antacid, adsorbent, enveloping,...

Indications: Acute gastritis; hyperacid gastritis; acute duodenitis; peptic ulcer of the stomach and duodenum (in the acute phase); symptomatic ulcers...

Laxomag

International name: Magnesium hydroxide

Pharmachologic effect: Antacid, has a mild laxative effect. Salt laxative: poorly absorbed, increases osmotic pressure in the lumen...

Indications: Gastralgia, heartburn (including after an error in diet, abuse of coffee, ethanol, smoking), duodenitis, gastritis (with normal or increased secretory function), peptic ulcer of the stomach and duodenum, constipation.

Magnesium hydroxide is an inorganic substance, it is a poorly soluble compound, which is why a precipitate appears when it is formed in aqueous solutions. The formula of magnesium hydroxide is Mg(OH) 2, that is, it is a diacid base. More soluble in water than typical insoluble bases, but less soluble than calcium hydroxide. For this reason, it is classified as a poorly soluble compound.

Distribution in nature

Magnesium hydroxide occurs naturally as the mineral brucite. Large deposits of this rock are very rare. In Russia, it is mined at the Kuldurskoye field, where its reserves are estimated at 14 million tons. Production on it is going at a rate of about 250 thousand tons of product per year, but since this year, production volumes have doubled. The reason for this was the good demand for this mineral abroad. The largest importer is Japan.

Brucite looks like white, gray or greenish-white crystals with a glassy sheen at the break. It has a fairly low hardness, so it can be easily cut with a knife. May contain impurities. Depending on their quantity and type, several subspecies of this mineral are distinguished. So, ferronemalite contains, in addition to magnesium hydroxide, 5% iron in the form of oxide, and ferrobrusite - already as much as 36%. Iron oxide has a brown color (the color of rust), so these minerals take on the same shade instead of the usual light green. There is also mangobrucite. Manganese acts as an impurity here. This mineral already has a honey-yellow color. But upon contact with atmospheric oxygen, the mineral quickly loses its beautiful color and quickly turns black.

This mineral is used mainly as a raw material. Oxide and other magnesium compounds, fluxes, and various refractory materials are obtained from it. But brucite can be used without any processing. So, this mineral is used to purify gases from chlorine and for sorption filtration of water.

Receipt

The main reaction for the production of insoluble hydroxides is the reaction of alkalis with magnesium salts. For example, when magnesium sulfate reacts with sodium hydroxide. This is a good illustration. Another example is the interaction of magnesium chloride and potassium hydroxide.

In ionic form, all such reactions are written as:

Mg 2+ + OH - → Mg(OH) 2

When magnesium or its oxide reacts with water, hydroxide can also be obtained. This reaction proceeds very slowly and only when heated.

There is such a fairly common mineral - dolomite. From a chemical point of view, it is a mixture of calcium carbonate and magnesium. When this mineral is treated with an aqueous solution of magnesium chloride and heated, an insoluble hydroxide precipitates:

MgCO 3 CaCO 3 + 2H 2 O + MgCl 2 → Mg(OH) 2 + CaCl 2 + 2CO 2

Physical properties

When dry, magnesium hydroxide is a white crystalline substance. It has no smell, but it has an inherent taste of alkali. It is slightly soluble in water (only 0.6 mg per 100 ml of water). But even despite this, its aqueous solutions have a slightly alkaline environment and color the indicators in the corresponding colors. But this compound dissolves in solutions of ammonium salts. It does not melt, since at a temperature of 480 o C it decomposes into magnesium oxide and water, like any other insoluble base. Density under normal conditions: 2.4 g/cm 3 .

Chemical properties

Magnesium hydroxide is a typical insoluble base. This determines its chemical properties. For example, magnesium hydroxide reacts with acids, acid oxides and non-metals:

Due to the latter reaction, it tends to absorb carbon dioxide directly from the air to form carbonate, so storing this substance open for a long time is not recommended.

It also interacts with salts if the reaction results in a precipitate or gas:

As mentioned above, when heated, magnesium hydroxide decomposes according to the equation:

Mg(OH) 2 → H 2 O + MgO

As for the formation of complex compounds where the magnesium cation would act as a ligand, there is conflicting information on this matter. Some sources indicate that magnesium is not prone to their formation, and there are only unstable compounds with magnesium halides. Other sources indicate that magnesium hydroxide can react with hot alkalis to form hydromagnesates:

Mg(OH) 2 + 2NaOH → Na 2

Application in medicine

In medicine, suspensions based on magnesium hydroxide are used as an antacid. This is facilitated by the main properties. Once in the stomach, magnesium hydroxide reduces its acidity by neutralizing hydrochloric acid. It is used for gastritis, peptic ulcer of the stomach and duodenum. Preparations based on it do not reduce the acid-base balance and do not violate the secretion of hydrochloric acid. But even despite this, the drug has a number of limitations and is contraindicated in people with hypersensitivity to magnesium hydroxide.

The product of the interaction of magnesium hydroxide and hydrochloric acid of gastric juice is magnesium chloride. It is a strong laxative (action occurs in 2-6 hours). Therefore, magnesium hydroxide is the active ingredient in some preparations in this area. Excess magnesium in the body is easily excreted by the kidneys, but if a person suffers from any diseases of these organs, then he can get an excess of magnesium in the body when taking drugs (hypermagnesemia).

Another property of this compound is muscle relaxation. Sometimes preparations containing magnesium hydroxide are prescribed to women with a threatened miscarriage.

Application in other industries

Magnesium hydroxide is also used in the food industry as an additive E528. In products, it regulates acidity and stabilizes color. Magnesium hydroxide is also used to bind sulfur dioxide, the appearance of which is undesirable in food products. It is used in the production of canned vegetables, sauces, marinade and cheese. This additive is considered harmless but is banned in Australia, the UK and New Zealand.

Magnesium hydroxide is also used as a flame retardant additive in polymers (PVC, polyolefins), as an additive in detergents and toothpastes, for sugar refining and wastewater treatment.

The oxide obtained from magnesium hydroxide is a rather useful compound. It is able to withstand temperatures of about 3000 degrees, so it is used as a refractory. So, it is added to bricks, from which blast furnaces are then made. Magnesium oxide is also used as a sorbent for the purification of petroleum products. The abrasive ability of this compound is also high. It is used to clean and polish the surfaces of parts in the electronics industry.

Used as a fertilizer.

Magnesium carbonate MgCO 3 . Colorless trigonal diamagnetic crystals. Slightly soluble in cold water. In hot water it turns into basic carbonates. Dissolves in acids. Decomposes on heating. Obtained by treating magnesium chloride or sulfate with sodium or calcium carbonate in excess of carbon dioxide. In industry, it can be obtained from natural minerals magnesite and dolomite.

It is used for the manufacture of refractory bricks, in the production of Sorel cement, as a filler for linoleum, rubber, and paper.

Magnesium bicarbonate Mg(HCO 3 ) 2 . Obtained in solution by passing carbon dioxide through an aqueous suspension of magnesium oxide, hydroxide or carbonate. The presence of magnesium bicarbonate in water causes its temporary hardness, which can be eliminated by boiling or adding soda.

Chemical properties of magnesium oxide and hydroxide

Magnesium oxide (burnt magnesia, periclase) is a chemical compound with the formula MgO, colorless crystals, insoluble in water, fire and explosion-proof. The main form is the mineral periclase.

Chemical properties

1) Reacts easily with dilute acids and water to form salts and Mg(OH) 2:

MgO + 2HCl> MgCl 2 + H 2 O;

MgO + H 2 O > Mg(OH) 2.

Magnesium hydroxide is an inorganic hydroxide of the alkaline earth metal magnesium. Belongs to the class of insoluble bases.

Chemical properties:

1) Decomposition when heated up to 350°C:

2) Reaction with acids to form salt and water (neutralization reaction):

3) Interaction with acid oxides to form salt and water:

4) Interaction with hot concentrated solutions of alkalis with the formation of hydroxomagnesates:

Ways to get an element.

The usual industrial method for producing magnesium metal is the electrolysis of a melt of a mixture of anhydrous magnesium chlorides MgCl 2, sodium NaCl and potassium KCl. In this melt, magnesium chloride undergoes electrochemical reduction:

MgCl 2 (electrolysis) = Mg + Cl 2.

The molten metal is periodically taken from the electrolysis bath, and new portions of magnesium-containing raw materials are added to it. Since the magnesium obtained in this way contains a relatively large amount - about 0.1% of impurities, if necessary, "raw" magnesium is subjected to additional purification. For this purpose, electrolytic refining, vacuum remelting with the use of special additives - fluxes, which “take away” impurities from magnesium, or distillation (sublimation) of the metal in vacuum are used. The purity of refined magnesium reaches 99.999% and higher.

Another method for obtaining magnesium has been developed - thermal. In this case, silicon or coke is used to reduce magnesium oxide at high temperatures:

magnesium chemical compound

MgO + C = Mg + CO

The use of silicon makes it possible to obtain magnesium from raw materials such as dolomite CaCO 3 ·MgCO 3 without preliminary separation of magnesium and calcium. The following reactions occur with the participation of dolomite:

CaCO 3 MgCO 3 = CaO + MgO + 2CO 2,

2MgO + 2CaO + Si = Ca 2 SiO 4 + 2Mg.

The advantage of the thermal method is that it allows one to obtain magnesium of higher purity. To obtain magnesium, not only mineral raw materials are used, but also sea water.

MAGNESIUM HYDROXIDE

MAGNESIUM HYDROXIDE: instructions for use and reviews

Active ingredient of the drug MAGNESIUM HYDROXIDE

magnesium hydroxide

Indications

Chronic gastritis with normal and increased secretory function in the acute phase - peptic ulcer of the stomach and duodenum in the acute phase - discomfort or pain in the epigastrium, heartburn after errors in diet, drinking coffee, alcohol, smoking - constipation.

pharmachologic effect

Antacid and laxative. Neutralizes free hydrochloric (hydrochloric) acid in the stomach, reduces the peptic activity of gastric juice. The effect of magnesium hydroxide is not accompanied by secondary hypersecretion of hydrochloric (hydrochloric) acid and changes in the acid-rich hormone. The laxative effect occurs after 0.5-6 hours. Magnesium hydroxide helps to increase peristalsis in all parts of the intestine.

Dosage

As an antacid: adults and children over 12 years of age are prescribed 0.3-1.2 g 4 times a day. A single dose for children from 3 to 12 years old is 400 mg; the frequency of administration is 3-4 times a day.

As a laxative, take at bedtime. In adults and children over 12 years of age, the dose is increased daily until the desired effect is obtained, on average the effective dose is 0.8-1.8 g.

Drug interactions

When used simultaneously with the absorption of dicumarol when used simultaneously with magnesium hydroxide.

With the simultaneous use of a combination of magnesium hydroxide and aluminum hydroxide with diflunisal, its bioavailability decreases.

When used simultaneously with iron salts, a decrease in iron absorption may occur.

With simultaneous use, the initial absorption of ibuprofen and flurbiprofen increases.

With simultaneous use, a decrease in the concentration of indomethacin in the blood plasma is possible. The irritating effect of indomethacin on the gastrointestinal tract is reduced.

When used simultaneously with captopril, a decrease in the AUC of captopril is possible.

With the simultaneous use of a combination of magnesium hydroxide and aluminum hydroxide with carbenoxolone, a decrease in its effectiveness is possible; with lansoprazole, a moderate decrease in its bioavailability is possible; with penicillamine, the absorption of penicillamine from the gastrointestinal tract is reduced; with sulpiride; a decrease in the absorption of sulpiride is possible; with prednisone and, apparently, with prednisolone - it is possible to reduce the absorption of GCS - with pyrazinamide - it is possible to slow down the rate, but not the degree of absorption of pyrazinamide - with quinidine - it is possible to increase its toxicity due to a significant increase in urine pH and a decrease in the excretion of quinidine - with cimetidine or ranitidine - it is possible to reduce the absorption of cimetidine and ranitidine.

With the simultaneous use of magnesium hydroxide with mefenamic acid, the absorption of mefenamic acid increases - with nitrofurantoin - a decrease in the absorption of nitrofurantoin is possible - with phenytoin - a slight decrease in the absorption of phenytoin is possible - with chlorpromazine - a decrease in the absorption of chlorpromazine is possible - with chlorpropamide - an increase in the absorption of chlorpropamide is possible.

Contraindications

Hypermagnesemia, hypersensitivity to magnesium hydroxide.

special instructions

For the drug MAGNESIUM HYDROXIDE:

In patients with impaired renal function, hypermagnesemia may develop when using magnesium hydroxide.

It is usually used in combination with aluminum-containing antacids to reduce side effects from the gastrointestinal tract and increase the duration of action.