Magnesium hydroxide - wikipedia Magnesium hydroxide Magnesium hydroxide Names IUPAC name Magnesium hydroxide Other names Milk of magnesia Identifiers CAS Number 1309 - 42 - 8 3D model ( JSmol ) Interactive image ChEBI CHEBI : 6637 ChEMBL ChEMBL1200718 ChemSpider 14107 ECHA InfoCard 100.013. 792 EC Number 215 - 170 - 3 E number E528 ( acidity regulators,... ) Gmelin Reference 485572 PubChem CID 14791 RTECS number OM3570000 UNII NBZ3QY004S InChI InChI = 1S / Mg. 2H2O / h ; 2 * 1H2 / q + 2 ; ; / p - 2 Key : VTHJTEIRLNZDEV - UHFFFAOYSA - L InChI = 1 / Mg. 2H2O / h ; 2 * 1H2 / q + 2 ; ; / p - 2 Key : VTHJTEIRLNZDEV - NUQVWONBAW SMILES ( Mg + 2 ). ( OH - ). ( OH - ) Properties Chemical formula Mg ( OH ) Molar mass 58.3197 g / mol Appearance White solid Odor Odorless Density 2.3446 g / cm Melting point 350 ° C ( 662 ° F ; 623 K ) decomposes Solubility in water 0.00064 g / 100 mL ( 25 ° C ) 0.004 g / 100 mL ( 100 ° C ) Solubility product ( K ) 5.61 × 10 Magnetic susceptibility ( χ ) − 22.1 10 cm / mol Refractive index ( n ) 1.559 Structure Crystal structure Hexagonal, hP3 Space group P3m1 No. 164 Lattice constant a = 0.312 nm, c = 0.473 nm Thermochemistry Specific heat capacity ( C ) 77.03 J / mol K Std molar entropy ( S ) 64 J mol K Std enthalpy of formation ( Δ H ) − 924.7 kJ mol Gibbs free energy ( Δ G  ̊ ) − 833.7 kJ / mol Pharmacology ATC code A02AA04 ( WHO ) G04BX01 ( WHO ) Hazards Safety data sheet External MSDS NFPA 704 0 0 Flash point Non-flammable Lethal dose or concentration ( LD, LC ) : LD ( median dose ) 8500 mg / kg ( rat, oral ) Related compounds Other anions Magnesium oxide Other cations Beryllium hydroxide Calcium hydroxide Strontium hydroxide Barium hydroxide Except where otherwise noted, data are given for materials in their standard state ( at 25 ° C ( 77 ° F ), 100 kPa ). N verify ( what is ? ) Infobox references Magnesium hydroxide is the inorganic compound with the chemical formula Mg ( OH ). It occurs in nature as the mineral brucite. It is a white solid with low solubility in water ( K = 5.61 × 10 ). Magnesium hydroxide is a common component of antacids, such as milk of magnesia, as well as laxatives. Contents 1 Preparation 2 Uses 2.1 Precursor to MgO 2.2 Health 2.2. 1 Metabolism 2.2. 2 History of milk of magnesia 2.3 Other niche uses 2.3. 1 Waste water treatment 2.3. 2 Fire retardant 3 Mineralogy 4 References Preparation Combining a solution of many magnesium salts with alkaline water induces precipitation of solid Mg ( OH ) : Mg + 2 OH → Mg ( OH ) On a commercial scale, Mg ( OH ) is produced by treating seawater with lime ( Ca ( OH ) ). 600 m of seawater gives about one ton of Mg ( OH ). Ca ( OH ) is far more soluble than Mg ( OH ), the latter precipitates as a solid : Mg + Ca ( OH ) → Mg ( OH ) + Ca Uses Precursor to MgO Most Mg ( OH ) that is produced industrially, as well as the small amount that is mined, is converted to fused magnesia ( MgO ). Magnesia is valuable because it is both a poor electrical conductor and an excellent thermal conductor. Health Metabolism When the patient drinks magnesium hydroxide, the suspension enters the stomach. Depending on how much was taken, one of two possible outcomes will occur. As an antacid, magnesium hydroxide is dosed at approximately 0.5 -- 1.5 g in adults and works by simple neutralization, where the hydroxide ions from the Mg ( OH ) combine with acidic H ions produced in the form of hydrochloric acid by parietal cells in the stomach to produce water. As a laxative, magnesium hydroxide is dosed at 2 -- 5 g, and works in a number of ways. First, Mg is poorly absorbed from the intestinal tract, so it draws water from the surrounding tissue by osmosis. Not only does this increase in water content soften the feces, it also increases the volume of feces in the intestine ( intraluminal volume ) which naturally stimulates intestinal motility. Furthermore, Mg ions cause the release of cholecystokinin ( CCK ), which results in intraluminal accumulation of water, electrolytes, and increased intestinal motility. Although it has been stated in some sources, the hydroxide ions themselves do not play a significant role in the laxative effects of milk of magnesia, as basic solutions ( i.e., solutions of hydroxide ions ) are not strongly laxative, and non-basic Mg solutions, like MgSO, are equally strong laxatives mole for mole. Only a small amount of the magnesium from magnesium hydroxide is usually absorbed by the intestine ( unless one is deficient in magnesium ). However, magnesium is mainly excreted by the kidneys so long - term, daily consumption of milk of magnesia by someone suffering from renal failure could lead in theory to hypermagnesemia. Unabsorbed drug is excreted in feces ; absorbed drug is excreted rapidly in urine. History of Milk of magnesia On May 4, 1818, American inventor John Callen received a patent ( No. X2952 ) for magnesium hydroxide. In 1829, Sir James Murray used a `` condensed solution of fluid magnesia '' preparation of his own design to treat the Lord Lieutenant of Ireland, the Marquis of Anglesey, of stomach pain. This was so successful ( advertised in Australia and approved by the Royal College of Surgeons in 1838 ) that he was appointed resident physician to Anglesey and two subsequent Lords Lieutenant, and knighted. His fluid magnesia product was patented two years after his death in 1873. The term milk of magnesia was first used by Charles Henry Phillips in 1872 for a suspension of magnesium hydroxide formulated at about 8 % w / v. It was sold under the brand name Phillips ' Milk of Magnesia for medicinal usage. Although the name may at some point have been owned by GlaxoSmithKline, USPTO registrations show `` Milk of Magnesia '' and `` Phillips ' Milk of Magnesia '' have both been assigned to Bayer since 1995. In the UK, the non-brand ( generic ) name of `` Milk of Magnesia '' and `` Phillips ' Milk of Magnesia '' is `` Cream of Magnesia '' ( Magnesium Hydroxide Mixture, BP ). Magnesium hydroxide is marketed for medical use as chewable tablets, as capsules, and as liquid suspensions, sometimes having various flavors added. These products are sold as antacids to neutralize stomach acid and relieve indigestion and heartburn. It also is a laxative to alleviate constipation. As a laxative, the osmotic force of the magnesia acts to draw fluids from the body. High doses can lead to diarrhea, and can deplete the body 's supply of potassium, sometimes leading to muscle cramps. Some magnesium hydroxide products sold for antacid use ( such as Maalox ) are formulated to minimize unwanted laxative effects through the inclusion of aluminum hydroxide, which inhibits the contractions of smooth muscle cells in the gastrointestinal tract, thereby counterbalancing the contractions induced by the osmotic effects of the magnesium hydroxide. Magnesium hydroxide is also a component of antiperspirant. Magnesium hydroxide is useful against canker sores ( aphthous ulcer ) when used topically. Other niche uses Waste water treatment Magnesium hydroxide powder is used industrially to neutralize acidic wastewaters. It also takes part in the Biorock method of building artificial reefs. Fire retardant Natural magnesium hydroxide ( brucite ) is used commercially as a fire retardant. Most industrially used magnesium hydroxide is produced synthetically. Like aluminium hydroxide, solid magnesium hydroxide has smoke suppressing and flame retardant properties. This property is attributable to the endothermic decomposition it undergoes at 332 ° C ( 630 ° F ) : Mg ( OH ) → MgO + H O The heat absorbed by the reaction retards the fire by delaying ignition of the associated substance. The water released dilutes combustible gases. Common uses of magnesium hydroxide as a flame retardant include additives to cable insulation ( i.e. cables for high quality cars, submarines, the Airbus A380, the Playstation 4, etc. ), insulation plastics, roofing ( e.g. London Olympic Stadium ), and various flame retardant coatings. Other mineral mixtures that are used in similar fire retardant applications are natural mixtures of huntite and hydromagnesite. Mineralogy Brucite crystals ( mineral form of Mg ( OH ) ) from the Sverdlovsk Region, Urals, Russia ( size : 10.5 × 7.8 × 7.4 cm ). Brucite, the mineral form of Mg ( OH ) commonly found in nature also occurs in the 1 : 2 : 1 clay minerals amongst others, in chlorite, in which it occupies the interlayer position normally filled by monovalent and divalent cations such as Na, K, Mg and Ca. As a consequence, chlorite interlayers are cemented by brucite and can not swell nor shrink. Brucite, in which some of the Mg cations have been substituted by Al cations, becomes positively charged and constitutes the main basis of layered double hydroxide ( LDH ). LDH minerals as hydrotalcite are powerful anion sorbents but are relatively rare in nature. Brucite may also crystallise in cement and concrete in contact with seawater. Indeed, the Mg cation is the second most abundant cation in seawater, just behind Na and before Ca. Because brucite is a swelling mineral, it causes a local volumetric expansion responsible for tensile stress in concrete. This leads to the formation of cracks and fissures in concrete, accelerating its degradation in seawater. For the same reason, dolostone can not be used as construction aggregate for making concrete. The reaction of magnesium carbonate with the free alkali hydroxides present in the cement porewater also leads to the formation of expansive brucite. MgCO + 2 NaOH → Mg ( OH ) + Na CO This reaction, one of the two main alkali - aggregate reaction ( AAR ) is also known as alkali - carbonate reaction. References Jump up ^ Pradyot Patnaik. Handbook of Inorganic Chemicals. McGraw - Hill, 2002, ISBN 0 - 07 - 049439 - 8 Jump up ^ Toshiaki Enoki and Ikuji Tsujikawa ( 1975 ). `` Magnetic Behaviours of a Random Magnet, NipMg ( 1 - p ) ( OH2 ) ''. J. Phys. Soc. Jpn. 39 ( 2 ) : 317 -- 323. doi : 10.1143 / JPSJ. 39.317. ^ Jump up to : Zumdahl, Steven S. ( 2009 ). Chemical Principles 6th Ed. Houghton Mifflin Company. p. A22. ISBN 0 - 618 - 94690 - X. Jump up ^ Handbook of Chemistry and Physics ( 76th ed. ). CRC Press. ISBN 0849305969. ^ Jump up to : Margarete Seeger ; Walter Otto ; Wilhelm Flick ; Friedrich Bickelhaupt ; Otto S. Akkerman ( 2005 ), `` Magnesium Compounds '', Ullmann 's Encyclopedia of Industrial Chemistry, Weinheim : Wiley - VCH, doi : 10.1002 / 14356007. a15_595. pub2 Jump up ^ Tedesco FJ, DiPiro JT ( 1985 ). `` Laxative use in constipation ''. Am. J. Gastroenterol. 80 ( 4 ) : 303 -- 9. PMID 2984923. Jump up ^ https://www.glowm.com/resources/glowm/cd/pages/drugs/m001.html Jump up ^ Patent USX2952 - Magnesia, medicated, liquid - Google Patents Jump up ^ Michael Hordern, A World Elsewhere ( 1993 ), p. 2. Jump up ^ `` Sir James Murray 's condensed solution of fluid magnesia ''. The Sydney Morning Herald. 21 ( 2928 ). October 7, 1846. p. 1, column 4. Jump up ^ Ulster History. Sir James Murray -- Inventor of Milk of Magnesia. 1788 to 1871 Archived 2011 - 06 - 05 at the Wayback Machine., 24 February 2005 Jump up ^ When was Phillips ' Milk of Magnesia introduced ? FAQ, phillipsrelief.com, accessed 4 July 2016 Jump up ^ results from the TARR web server : Milk of Magnesia Jump up ^ results from the TARR web server : Phillips ' Milk of Magnesia Jump up ^ Magnesium Hydroxide -- Revolution Health Jump up ^ Washington, Neena ( 2 August 1991 ). Antacids and Anti Reflux Agents. Boca Raton, FL : CRC Press. p. 10. ISBN 0 - 8493 - 5444 - 7. Jump up ^ Milk of Magnesia Makes Good Antiperspirant Jump up ^ Canker sores, 2 / 1 / 2009 Jump up ^ Aileen Gibson and Michael Maniocha White Paper : The Use Of Magnesium Hydroxide Slurry For Biological Treatment Of Municipal and Industrial Wastewater, August 12, 2004 Jump up ^ Rothon, RN ( 2003 ). Particulate Filled Polymer Composites. Shrewsbury, UK : Rapra Technology. pp. 53 -- 100. Jump up ^ Hollingbery, LA ; Hull TR ( 2010 ). `` The Thermal Decomposition of Huntite and Hydromagnesite - A Review ''. Thermochimica Acta. 509 ( 1 - 2 ) : 1 -- 11. doi : 10.1016 / j. tca. 2010.06. 012. Jump up ^ Hollingbery, LA ; Hull TR ( 2010 ). `` The Fire Retardant Behaviour of Huntite and Hydromagnesite - A Review ''. Polymer Degradation and Stability. 95 ( 12 ) : 2213 -- 2225. doi : 10.1016 / j. polymdegradstab. 2010.08. 019. Jump up ^ Hollingbery, LA ; Hull TR ( 2012 ). `` The Fire Retardant Effects of Huntite in Natural Mixtures with Hydromagnesite ''. Polymer Degradation and Stability. 97 ( 4 ) : 504 -- 512. doi : 10.1016 / j. polymdegradstab. 2012.01. 024. Jump up ^ Hollingbery, LA ; Hull TR ( 2012 ). `` The Thermal Decomposition of Natural Mixtures of Huntite and Hydromagnesite ''. Thermochimica Acta. 528 : 45 -- 52. doi : 10.1016 / j. tca. 2011.11. 002. Jump up ^ Hull, TR ; Witkowski A ; Hollingbery LA ( 2011 ). `` Fire Retardant Action of Mineral Fillers ''. Polymer Degradation and Stability. 96 ( 8 ) : 1462 -- 1469. doi : 10.1016 / j. polymdegradstab. 2011.05. 006. Magnesium compounds MgB MgBr MgCO MgC O MgC H O MgC H O MgCl Mg ( ClO ) MgF MgH Mg ( HCO ) MgI Mg ( NO ) MgO MgO Mg ( OH ) MgPo MgS MgSO MgSO MgU O Mg Al Mg Si Mg SiO Mg Si O Mg N Mg ( PO ) Mg ( CrO ) Hydroxides H O He LiOH Be ( OH ) NH H O O Ne NaOH Mg ( OH ) Al ( OH ) Si Cl Ar KOH Ca ( OH ) Sc ( OH ) Ti V Cr ( OH ) Cr ( OH ) Mn ( OH ) Fe ( OH ) Fe ( OH ) Co ( OH ) Ni ( OH ) CuOH Cu ( OH ) Zn ( OH ) Ga ( OH ) Ge ( OH ) As Se Br Kr RbOH Sr ( OH ) Y ( OH ) Zr ( OH ) Nb Mo Tc Ru Rh Pd AgOH Cd ( OH ) In ( OH ) Sn ( OH ) Sn ( OH ) Sb ( OH ) Te Xe CsOH Ba ( OH ) * Hf Ta Re Os Ir Pt Au ( OH ) Hg ( OH ) TlOH Tl ( OH ) Pb ( OH ) Pb ( OH ) Bi ( OH ) Po At Rn Fr Ra * * Rf Db Sg Bh Hs Mt Ds Rg Cn Nh Fl Mc Lv Ts Og ↓ * La ( OH ) Ce ( OH ) Pr ( OH ) Nd ( OH ) Pm ( OH ) Sm ( OH ) Eu ( OH ) Gd ( OH ) Tb ( OH ) Dy ( OH ) Ho ( OH ) Er ( OH ) Tm ( OH ) Yb ( OH ) Lu ( OH ) * * Ac Th ( OH ) Pa UO ( OH ) Np Pu Am Cm ( OH ) Bk Cf Es Fm Md No Lr Urologicals, including antispasmodics ( G04B ) Acidifiers Ammonium chloride Calcium chloride Urinary antispasmodics ( primarily antimuscarinics ) Darifenacin Desfesoterodine Emepronium Fesoterodine Flavoxate Imidafenacin Meladrazine Mirabegron Oxybutynin Propiverine Solifenacin Terodiline Tolterodine Trospium chloride Other urologicals Urea analogues : Acetohydroxamic acid Salicylhydroxamic acid Other : Collagen Dimethyl sulfoxide Magnesium hydroxide Pentosan polysulfate Phenazopyridine Phenyl salicylate Succinimide Drugs for acid related disorders : Antacids ( A02A ) Magnesium ( increases motility ) Magnesium carbonate Magnesium oxide Magnesium peroxide Magnesium hydroxide Magnesium silicate Aluminium ( decreases motility ) Aceglutamide aluminum Algeldrate Aluminium phosphate Aluminium acetoacetate Aloglutamol Aluminium glycinate Carbaldrate Calcium Calcium carbonate Calcium silicate Sodium Sodium bicarbonate Combinations and complexes of aluminium, calcium and magnesium Almagate Almasilate Hydrotalcite Magaldrate Drugs for constipation ( laxatives and cathartics ) ( A06 ) Stool softeners Docusate Stimulant laxatives Bisacodyl Bisoxatin Cascara Castor oil Dantron Oxyphenisatine Phenolphthalein Senna glycosides Sodium picosulfate Bulk - forming laxatives Dietary fiber Ethulose Ispaghula Methylcellulose Polycarbophil calcium Sterculia Triticum Lubricant laxatives Liquid paraffin Mineral oil White petrolatum ( petroleum jelly ) Osmotic laxatives Lactitol Lactulose Laminarid Magnesium carbonate Magnesium citrate Magnesium hydroxide ( milk of magnesia ) Magnesium oxide Magnesium peroxide Magnesium sulfate Mannitol Pentaerythritol Polyethylene glycol ( macrogol ) Sodium phosphate Sodium sulfate Sodium tartrate Sorbitol Enemas Bisacodyl Dantron Glycerol Oil Sodium laurilsulfate Sodium lauryl sulfoacetate Sodium phosphate Sorbitol Opioid antagonists Alvimopan Methylnaltrexone bromide Naloxegol Naloxone ( Oxycodone / naloxone ) Others Linaclotide Lubiprostone Oxyphenisatine Prucalopride Tegaserod Ulimorelin Retrieved from `` https://en.wikipedia.org/w/index.php?title=Magnesium_hydroxide&oldid=836392208 '' Categories : Antacids Laxatives Food acidity regulators Bases ( chemistry ) Hydroxides Magnesium compounds Hidden categories : CS1 : Julian -- Gregorian uncertainty Webarchive template wayback links Articles without KEGG source Articles with changed EBI identifier ECHA InfoCard ID from Wikidata E number from Wikidata Articles containing unverified chemical infoboxes Chembox image size set Talk Contents About Wikipedia Afrikaans تۆرکجه Català Čeština Cymraeg Deutsch Ελληνικά Español Euskara فارسی Français Gaeilge 한국어 हिन्दी Bahasa Indonesia Italiano עברית Magyar Nederlands 日本 語 Polski Português Română Русский Slovenščina Српски / srpski Srpskohrvatski / српскохрватски Suomi Svenska ไทย Türkçe Українська Tiếng Việt 中文 26 more Edit links This page was last edited on 14 April 2018, at 14 : 35. 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Question: what is the molar mass of magnesium hydroxide
Answer: 58.3197 g/mol