Magnesium hydroxide

From Wikipedia, the free encyclopedia

It has been suggested that this article or section be merged with Milk of Magnesia. (Discuss)

**Properties**
General

Name	Magnesium hydroxide
Chemical formula	Mg(OH)₂
Molar mass	58.33 g/mol
Appearance	White solid
Physical
Melting point	Decomposes at 623 K (350 °C)
pK_b	-0.85
Density	2.4 g/cm³
Crystal structure	?
Solubility	0.0012 g in 100 g water
Thermochemistry
Δ_fH⁰_gas	-561 kJ/mol
Δ_fH⁰_solid	-925 kJ/mol
S⁰_solid	63 J/(mol·K)
Safety
Ingestion	Safe in small amounts, but large amounts can be dangerous.
Inhalation	May cause irritation.
Skin	May cause irritation.
Eyes	May cause irritation.
More info	Hazardous Chemical Database
SI units were used where possible. Unless otherwise stated, standard conditions were used. Disclaimer and references

Magnesium hydroxide, Mg(OH)₂, otherwise known as milk of magnesia, is commonly used as an antacid or a laxative. The mineral form of magnesium hydroxide is known as brucite. Magnesium hydroxide interferes with the absorption of folic acid and iron. The diarrhea caused by magnesium hydroxide carries away much of the body's supply of potassium, and failure to take extra potassium will lead to muscle cramps.

It has very low solubility in water, and has a K_sp value of 1.5x10^-11.

It is a strong base.

[edit] Preparation

From a Magnesium salt:

$Mg_3N_2 + 6H_2O \rightarrow 2NH_3 + 3Mg(OH)_2$

In words:

Solid Magnesium nitride + Water = Ammonia + Aqueous Magnesium Hydroxide

From a Magnesium base:

$MgO + H_2O \rightarrow Mg(OH)_2$

In words:

Solid Magnesium oxide + Water = Aqueous Magnesium Hydroxide

From pure Magnesium metal:

$Mg_(s) + 2H_2O_(g) \rightarrow Mg(OH)_2(aq) + H_2(g)$

In Words:

Solid Magnesium + Water = Aqueous Magnesium Hydroxide + Hydrogen Gas

[edit] Uses

Magnesium hydroxide is used as an antacid to remove stomach acid. In industry, it is used as a non hazardous alkali to neutralise acidic wastewaters.

[edit] External links

Links to external chemical sources

v • d • e Urologicals (G04)
Acidifiers	Ammonium chloride, Calcium chloride
Urinary antispasmodics	Darifenacin, Emepronium, Flavoxate, Meladrazine, Oxybutynin, Propiverine, Solifenacin, Terodiline, Tolterodine, Trospium
For erectile dysfunction	Alprostadil, Apomorphine, Avanafil, Moxisylyte, Papaverine, Phentolamine, Sildenafil, Tadalafil, Udenafil, Vardenafil, Vendafidel, Yohimbine
Other urologicals	Acetohydroxamic acid, Collagen, Dimethyl sulfoxide, Magnesium hydroxide, Phenazopyridine, Phenyl salicylate, Succinimide
For benign prostatic hypertrophy	5α-reductase inhibitors: Dutasteride, Finasteride Alpha blockers: Alfuzosin, Doxazosin, Tamsulosin, Terazosin Herbals: Pygeum africanum, Serenoa repens