Magnesium hydroxide CAS#1309-42-8

Long-Lasting Antacid & Laxative Action – Reacts slowly with stomach acid and retains water in the intestine, providing sustained relief from acidity and constipation.
Effective Flame Retardant & Smoke Suppressant – Decomposes endothermically at 332 °C, releasing water and magnesia to reduce heat and suppress smoke in fire-resistant applications.
Versatile Industrial Applications – Widely used in wastewater treatment, fuel additives, and as a raw material for producing various magnesium salts.
Stable Aqueous Suspension – Forms a uniform suspension in water with controlled solubility, ensuring reliable performance in pharmaceutical and industrial formulations.

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Product Details

Magnesium Hydroxide CAS#1309-42-8

Magnesium hydroxide is widely known as the main active component in Milk of Magnesia, a traditional antacid and laxative that has been used for more than 150 years. It forms a suspension in water and reacts slowly with gastric acid, providing a prolonged neutralizing effect. At higher dosages, its laxative action is mainly due to water retention in the intestine, as it is not absorbed by the large intestine, helping to relieve constipation.

In addition to pharmaceutical use, magnesium hydroxide is applied as a flame retardant and smoke suppressant. When heated to about 332 °C, it undergoes endothermic decomposition, releasing water and forming magnesium oxide, which helps reduce heat and smoke. It is also used in wastewater treatment, as a fuel additive, and as a raw material for the manufacture of magnesium salts.

Magnesium hydroxide CAS#1309-42-8

Magnesium hydroxide Chemical Properties

Melting point	350 °C (lit.)
density	2,36 g/cm3
storage temp.	Room Temperature
solubility	5 M HCl: 0.1 M, clear, yellow
form	powder
color	White
Specific Gravity	2.36
Odor	Odorless
PH	10.4(1 mM solution);10.4(10 mM solution);10.4(100 mM solution)
PH Range	9.5 - 10.5
Water Solubility	0.9 mg/100 mL (18 ºC)
λmax	λ: 260 nm Amax: 0.030
λmax	λ: 280 nm Amax: 0.025
Sensitive	Air Sensitive
Merck	145,670
Solubility Product Constant (Ksp)	pKsp: 11.25
Stability:	Stable.
Cosmetics Ingredients Functions	ABSORBENT
Cosmetics Ingredients Functions	BUFFERING
InChIKey	VTHJTEIRLNZDEV-UHFFFAOYSA-L
LogP	-1.380 (est)
CAS DataBase Reference	1309-42-8(CAS DataBase Reference)
NIST Chemistry Reference	Magnesium hydroxide(1309-42-8)
EPA Substance Registry System	Magnesium hydroxide (Mg(OH)2) (1309-42-8)

Safety Information

Hazard Codes	Xi
Risk Statements	36/37/38
Safety Statements	26-36-37/39-24/25
WGK Germany	-
RTECS	OM3570000
F	3月9日
TSCA	Yes
HS Code	28161000
Hazardous Substances Data	1309-42-8(Hazardous Substances Data)
Toxicity	LD50 oral in rat: 8500mg/kg

Product Application of Magnesium Hydroxide CAS#1309-42-8

Magnesium hydroxide is widely used as a flame retardant in plastics, rubber, and coatings, offering smoke-free, non-toxic, and non-corrosive performance with high thermal stability. In environmental protection, it serves as a flue-gas desulfurization absorbent and an effective neutralizer for acidic wastewater and heavy metals, replacing caustic soda and lime.

It is also applied in electronics, pharmaceuticals, sugar refining, insulation materials, and the production of magnesium salts. In medicine and food processing, it is used as an antacid, laxative, mineral additive, and alkalizing agent. With its higher decomposition temperature compared to aluminum hydroxide, magnesium hydroxide is especially suitable for high-temperature processing in polyethylene, polypropylene, PVC, EPDM, polyester resins, and flame-retardant paints.

Magnesium hydroxide CAS#1309-42-8