Hydrate - Wikipedia

In chemistry, a hydrate is a substance that contains water or its constituent elements. The chemical state of the water varies widely between different ... Hydrate FromWikipedia,thefreeencyclopedia Jumptonavigation Jumptosearch Substancecontainingwateroritsconstituentelements Thisarticleisaboutchemicalcompounds.Forhydrationinhumansoranimals,seedrinking. Inchemistry,ahydrateisasubstancethatcontainswateroritsconstituentelements.Thechemicalstateofthewatervarieswidelybetweendifferentclassesofhydrates,someofwhichweresolabeledbeforetheirchemicalstructurewasunderstood. Contents 1Chemicalnature 1.1Inorganicchemistry 1.2Organicchemistry 1.3Clathratehydrates 2Stability 3Seealso 4References Chemicalnature[edit] Inorganicchemistry[edit] Mainarticle:waterofcrystallization Hydratesareinorganicsalts"containingwatermoleculescombinedinadefiniteratioasanintegralpartofthecrystal"[1]thatareeitherboundtoametalcenterorthathavecrystallizedwiththemetalcomplex.Suchhydratesarealsosaidtocontainwaterofcrystallizationorwaterofhydration.Ifthewaterisheavywaterinwhichtheconstituenthydrogenistheisotopedeuterium,thenthetermdeuteratemaybeusedinplaceofhydrate.[citationneeded] Anhydrouscobalt(II)chlorideCoCl2(blue) Cobalt(II)chloridehexahydrateCoCl2·6H2O(pink) Acolorfulexampleiscobalt(II)chloride,whichturnsfrombluetoreduponhydration,andcanthereforebeusedasawaterindicator. Thenotation"hydratedcompound⋅nH2O",wherenisthenumberofwatermoleculesperformulaunitofthesalt,iscommonlyusedtoshowthatasaltishydrated.Thenisusuallyalowinteger,thoughitispossibleforfractionalvaluestooccur.Forexample,inamonohydraten = 1,andinahexahydraten = 6.NumericalprefixesmostlyofGreekoriginare:[2] Hemi–1⁄2 Mono–1 Sesqui–1+1⁄2 Di–2 Tri–3 Tetra–4 Penta–5 Hexa–6 Hepta–7 Octa–8 Nona–9 Deca–10 Undeca–11 Dodeca–12 Ahydratethathaslostwaterisreferredtoasananhydride;theremainingwater,ifanyexists,canonlyberemovedwithverystrongheating.Asubstancethatdoesnotcontainanywaterisreferredtoasanhydrous.Someanhydrouscompoundsarehydratedsoeasilythattheyaresaidtobehygroscopicandareusedasdryingagentsordesiccants. Organicchemistry[edit] Inorganicchemistry,ahydrateisacompoundformedbythehydration,i.e."Additionofwateroroftheelementsofwater(i.e.HandOH)toamolecularentity".[3]Forexample:ethanol,CH3−CH2−OH,istheproductofthehydrationreactionofethene,CH2=CH2,formedbytheadditionofHtooneCandOHtotheotherC,andsocanbeconsideredasthehydrateofethene.Amoleculeofwatermaybeeliminated,forexample,bytheactionofsulfuricacid.Anotherexampleischloralhydrate,CCl3−CH(OH)2,whichcanbeformedbyreactionofwaterwithchloral,CCl3−CH=O. Manyorganicmolecules,aswellasinorganicmolecules,formcrystalsthatincorporatewaterintothecrystallinestructurewithoutchemicalalterationoftheorganicmolecule(waterofcrystallization).Thesugartrehalose,forexample,existsinbothananhydrousform(meltingpoint203 °C)andasadihydrate(meltingpoint97 °C).Proteincrystalscommonlyhaveasmuchas50%watercontent. Moleculesarealsolabeledashydratesforhistoricalreasonsnotcoveredabove.Glucose,C6H12O6,wasoriginallythoughtofasC6(H2O)6anddescribedasacarbohydrate. Hydrateformationiscommonforactiveingredients.Manymanufacturingprocessesprovideanopportunityforhydratestoformandthestateofhydrationcanbechangedwithenvironmentalhumidityandtime.Thestateofhydrationofanactivepharmaceuticalingredientcansignificantlyaffectthesolubilityanddissolutionrateandthereforeitsbioavailability.[4] Clathratehydrates[edit] Mainarticle:Clathratehydrate Clathratehydrates(alsoknownasgashydrates,gasclathrates,etc.)arewatericewithgasmoleculestrappedwithin;theyareaformofclathrate.Animportantexampleismethanehydrate(alsoknownasgashydrate,methaneclathrate,etc.). Nonpolarmoleculessuchasmethanecanformclathratehydrateswithwater,especiallyunderhighpressure.Althoughthereisnohydrogenbondingbetweenwaterandguestmoleculeswhenmethaneistheguestmoleculeoftheclathrate,guest–hosthydrogenbondingoftenformswhentheguestisalargerorganicmoleculesuchastetrahydrofuran.Insuchcasestheguest–hosthydrogenbondsresultintheformationofL-typeBjerrumdefectsintheclathratelattice.[5] Stability[edit] Thestabilityofhydratesisgenerallydeterminedbythenatureofthecompounds,theirtemperature,andtherelativehumidity(iftheyareexposedtoair). Seealso[edit] Efflorescence Hygroscopy Mineralhydration Waterofcrystallization Hemihydrate Hydrousoxide References[edit] ^Greenwood,NormanN.;Earnshaw,Alan(1997).ChemistryoftheElements(2nd ed.).Butterworth-Heinemann.p. 625.ISBN 978-0-08-037941-8. ^NomenclatureofInorganicChemistry.IUPACRecommendations2005.TableIVMultiplicativePrefixes,p. 258. ^IUPAC,CompendiumofChemicalTerminology,2nded.(the"GoldBook")(1997).Onlinecorrectedversion: (2019)"Hydration".doi:10.1351/goldbook.H02876 ^Surov,ArtemO.,NikitaA.Vasilev,AndreiV.Churakov,JuliaStroh,FranziskaEmmerling,andGermanL.Perlovich."SolidFormsofCiprofloxacinSalicylate:Polymorphism,FormationPathwaysandThermodynamicStability".CrystalGrowth&Design(2019).doi:10.1021/acs.cgd.9b00185. ^AlaviS.,SusiloR.,RipmeesterJ.A.(2009)."Linkingmicroscopicguestpropertiestomacroscopicobservablesinclathratehydrates:guest-hosthydrogenbonding"(PDF).TheJournalofChemicalPhysics.130(17):174501.Bibcode:2009JChPh.130q4501A.doi:10.1063/1.3124187.PMID 19425784.CS1maint:usesauthorsparameter(link) Retrievedfrom"https://en.wikipedia.org/w/index.php?title=Hydrate&oldid=1058544031" Categories:HydratesHiddencategories:CS1maint:usesauthorsparameterArticleswithshortdescriptionShortdescriptionisdifferentfromWikidataAllarticleswithunsourcedstatementsArticleswithunsourcedstatementsfromSeptember2013 Navigationmenu Personaltools NotloggedinTalkContributionsCreateaccountLogin Namespaces ArticleTalk Variants expanded collapsed Views ReadEditViewhistory More expanded collapsed Search Navigation MainpageContentsCurrenteventsRandomarticleAboutWikipediaContactusDonate Contribute HelpLearntoeditCommunityportalRecentchangesUploadfile Tools WhatlinkshereRelatedchangesUploadfileSpecialpagesPermanentlinkPageinformationCitethispageWikidataitem Print/export DownloadasPDFPrintableversion Inotherprojects WikimediaCommons Languages AfrikaansالعربيةAzərbaycancaБеларускаяБългарскиCatalàČeštinaDanskDeutschEestiEspañolEsperantoفارسیFrançaisGaeilgeGalego한국어ՀայերենHrvatskiIdoBahasaIndonesiaItalianoҚазақшаKreyòlayisyenКыргызчаBahasaMelayuNederlands日本語NorskbokmålOʻzbekcha/ўзбекчаPolskiPortuguêsRomânăРусскийСрпски/srpskiSrpskohrvatski/српскохрватскиSuomiУкраїнськаاردوTiếngViệt吴语中文 Editlinks