Abriefhistoryofdiscovery
In1787,Lavoisierfirstdiscoveredsiliconinrocks.
In1800,Davidmistakenitforacompound.
In1811,Guy-LussacandTanner(Thenard,LouisJacques)heatedpotassiumandsilicontetrafluoridetoobtainimpureamorphoussilicon,whichwasnamedsiliconaccordingtotheLatinsilex(flint).
In1811,Gay-LussacandThenardusedsilicon(silicon)tetrafluoridetoreactwithalkalineearthmetalsanddiscoveredthatarussetcompound(probablyamorphoussiliconcontainingimpurities)wasformedduringthereaction.
In1823,siliconwasfirstdiscoveredasanelementbyJonsJacobsBezelius.Ayearlater,amorphoussiliconwasextracted.Gramusesroughlythesamemethod.Hethenusedrepeatedcleaningmethodstopurifytheelementalsilicon.
In1823,Berzeliususedsiliconoxide(silicon)powderandamixtureofironandcarbontoheatitathightemperaturestoobtainironsilicide.Butinordertoextractpuresilicon(silicon),heusesacompoundofsilicon(silicon)-fluorine-calcium,andthesolidobtainedafterdryburningishydrolyzedtoobtainpuresilicon(silicon).
ThehonorofdiscoveringsiliconbelongstotheSwedishchemistJönsJacobBerzelius,whoobtainedsiliconbyheatingpotassiumandpotassiumfluorosilicateinStockholm(thecapitalofSweden)in1824.Thisproductwascontaminatedbypotassiumsilicate,buthestirreditinwaterandreactedwithit,thusobtainingrelativelypuresiliconpowder.
In1824,JonsJacobsBezeliususedthesamemethod,butafterrepeatedwashingtoremovefluorosilicicacid,pureamorphoussiliconwasobtained.
Thecrystallinesiliconwasnotrefineduntil1854.TheLatinwordforsilicon(silicon)issilicium,whichmeans"hardstone".
In1854,H·S·C·Devillemadecrystallinesiliconforthefirsttime.
Theoriginofthenameofsilicon:Englishsilicon,fromtheLatinsilex,silicis,meaningflint(flint).IntheearlydaysoftheRepublicofChina,scholarsoriginallytranslatedthiselementas"silicon"andpronounceditas"xi(youcanreadxisoundbythesideofGui)"(also,"silicon"isavariantof"砉",pronouncedhuo).However,inthetimeandspaceatthattime,sincethepinyinschemehasnotbeenpopularizedyet,itisgenerallymisreadasgui.InadditiontotheoriginalChinesename,transliterationisoftenusedforthetranslationofchemicalelements.TheSocietyofChemistrynoticedthisproblemandcreatedtheword"silicon"toavoidmisunderstandings.Taiwanstillusestheword"silicon"tothisday.InMainlandChina,inFebruary1953,theChineseAcademyofSciencesheldanationwidesymposiumonthenamingofchemicalsubstances.Somescholarsadoptedandannouncedthat"silicon"iseasilyconfusedwithotherchemicalelements"tin"and"selenium".Changedbacktotheoriginalname"Si"andpronounced"gui",butdidnotrealizethat"Si"shouldalsobepronouncedxi.Interestingly,wordssuchassilicosisandsiliconsteelsheetstillusethewordsilicon.InHongKong,bothareused,but"silicon"ismorecommon.
Distributionofmineraldeposits
Theabundanceofsiliconarousedtheinterestofearlychemists.Thecontentofsilicon(silicon)onthesurfaceoftheearthissecondonlytooxygen,accountingfornearly28%.However,silicon(silicon)isnotthefirstelementtobediscovered.Thatisbecausesiliconisreducedfromtheoxideofsilicon(silicon).Averydifficultthing.
Siliconaccountsforabout25.7%ofthetotalweightoftheearth'scrust,secondonlytooxygen.Innature,siliconusuallyexistsintheformofoxygen-containingcompounds,thesimplestofwhichissilicaSiO2,acompoundofsiliconandoxygen.Quartz,crystal,etc.arevariantsofpuresilica.Silicacompoundsinoresandrocksarecollectivelyreferredtoassilicates.ThemoreimportantonesarefeldsparKAlSi3O8andkaolinAl2Si2O5(OH)4,talcMg3(Si4O10)(OH)2,MicaKAl2(AlSi3O10)(OH)2,asbestosH4Mg3Si2O9,SodiumzeoliteNa2(Al2Si3O10)·2H2O,garnetCa3Al2(SiO4)3,ZirconiumQuartzZrSiO4andBerylBe3Al2Si6O18Wait.Soil,clayandsandaretheweatheredproductsofnaturalsilicaterocks.
Siliconiswidelydistributedinnature,anditsatomicpercentageintheearth'scrustis16.7%.Itisabasicelementcomposingrockminerals,appearingasquartzsandandsilicate.
Thecontentofsiliconintheearth'scrustisthemostabundantelementexceptoxygen.Ifcarbonisthebasisofallorganiclife,thensiliconoccupiesthesameplaceintheearth'scrust,becausethemainpartoftheearth'scrustiscomposedofsilicon-containingrocklayers.Almostalloftheserocksarecomposedofsilicaandvarioussilicates.Feldspar,mica,clay,olivine,hornblende,etc.areallsilicates;crystal,agate,jasper,opal,quartz,sandandflintareallsilica.
Physicalandchemicalproperties
Physicalproperties
Therearetwoallotropesofamorphoussiliconandcrystallinesilicon.Crystallinesiliconisgray-black,amorphoussiliconisblack,density2.32-2.34g/cm3,meltingpoint1410℃,boilingpoint2355℃,crystallinesiliconbelongstoatomiccrystal.Itisinsolubleinwater,nitricacidandhydrochloricacid,butsolubleinhydrofluoricacidandlye.Hardandmetallic.
series | metal-like |
family | IVAfamily |
period | 3 |
ElementPartition | PArea |
Commonvalences | -4,+4 |
Hardness | 6.5 |
Crustalcontent | 25.7% |
Elasticmodulus | 190GPa |
Density | 2.33g/cm³(18°C) |
Meltingpoint | 1687K(1414°C) |
Boilingpoint | 3173K(2900℃) |
Molevolume | 12.06×10-6m3/mol |
Heatofvaporization | 384.22kJ/mol |
Heatoffusion | 50.55kJ/mol |
Vaporpressure | 4.77Pa(1683K) |
Indirectbandgap | 1.1eV(Roomtemperature) |
Conductivity | 2.52×10-4/(meterohm) |
Electronegativity | 1.90(Paulingscale) |
Specificheat p> | 700J/(kg·K) |
Electronicarrangementoutsidethenucleus:1s²2s²2p⁶3s²3p²
Unitcelltype:cubicdiamondtype;
Unitcellparameter:measuredat20℃,itsunitcellparametera=0.543087nm;
ColorAndappearance:darkgraywithbluishtint;
TheEofsinglecrystalsilicon(100)measuredbynanoindentationmethodis140～150GPa;
Conductivity:Silicon’sconductivityTheratehasagreatrelationshipwithitstemperature.Asthetemperaturerises,theconductivityincreases,reachingamaximumaround1480℃,andafterthetemperatureexceeds1600℃,itdecreaseswiththeincreaseintemperature.
Electronegativity | 1.90(Paulingscale) p> |
Thermalconductivity | 148W/(m·K) |
Firstionizationenergy | 786.5kJ/mol |
Secondionizationenergy | 1577.1kJ/mol |
Thirdionizationenergy | 3231.6kJ/mol |
Fourthionizationenergy | 4355.5kJ/mol |
Fifthionizationenergy | 16091kJ/mol |
Sixthionizationenergy | 19805kJ/mol |
TheseventhIonizationenergy | 23780kJ/mol |
Eighthionizationenergy | 29287kJ/mol |
Ninthionizationenergy | 33878kJ/mol |
Tenthionizationenergy | 38726kJ/mol |
Isotopes:
22Si | 14 | 8 | 22.03453(22)# | 29(2)ms | 0+ | ||
23Si | 14 | 9 | 23.02552(21)# | 42.3(4)ms | 3/2+# | ||
24Si | 14 | 10 | 24.011546(21) | 140(8)ms | 0+ | ||
25Si | 14 | 11 | 25.004106(11) | 220(3)ms | 5/2+ | ||
26Si | 14 | 12 | 25.992330(3) | 2.234(13)s | 0+ | ||
27Si | 14 | 13 | 26.98670491(16) | 4.16(2)s | 5/2+ | ||
28Si | 14 | 14 | 27.9769265325(19) | stable | 0+ | 0.92223(19) | 0.92205-0.92241 | tr>
29Si | 14 | 15 | 28.976494700(22) | Stable | 1/2+ | 0.04685(8) | 0.04678-0.04692 |
30Si | 14 | 16 | 29.97377017(3) | Stable | 0+ | 0.03092(11) | 0.03082-0.03102 |
31Si | 14 | 17 | 30.97536323(4) | 157.3(3)min | 3/2+ | ||
32Si | 14 | 18 | 31.97414808(5) | 170(13)a | 0+ | ||
33Si | 14 | 19 | 32.978000(17) | 6.18(18)s | (3/2+) | tr> | |
34Si | 14 | 20 | 33.978576(15) | 2.77(20)s | 0+ | ||
35Si | 14 | 21 | 34.98458(4) | 780(120)ms | 7/2-# | ||
36Si | 14 | 22 | 35.98660(13) | 0.45(6)s p> | 0+ | ||
37Si | 14 | 23 | 36.99294(18) | 90(60)ms | （7/2-)# | ||
38Si | 14 | 24 | 37.99563(15) | 90#ms | 0+ | ||
39Si | 14 | 25 | 39.00207(36) | 47.5(20)ms | 7/2-# | ||
40Si | 14 | 26 | 40.00587(60) | 33.0(10)ms | 0+ | ||
41Si | 14 | 27 | 41.01456(198) | 20.0(25)ms | 7/2-# | ||
42Si | 14 | 28 | 42.01979(54)# | 13(4)ms | 0+ | ||
43Si | 14 | 29 | 43.02866(75)# | 15#ms | 3/2-# | ||
44Si | 14 | 30 | 44.03526(86)# | 10#ms | 0+ |
Remarks:1.Thedatamarkedwith#indicatesthatthereisnoexperimentalproof,butonlytheoreticalspeculation,andthedataenclosedinbracketsrepresentstheuncertaintyofthedata.
2.TherearethreenaturalstableisotopesSi-28(92.2%),Si-29(4.7%)andSi-30(3.1%),andthemassnumbersare25,26,27,Artificialradioisotopesof31and32.
3.Silicon(atomicmassunit:28.0855,thereare23isotopesintotal,ofwhich3isotopesarestable.
Chemicalproperties
SiliconhasobviousThenon-metallicpropertiesofsiliconcanbedissolvedinalkalimetalhydroxidesolutiontoproduce(meta)silicateandhydrogen.
ThesiliconatomislocatedintheIVmaingroupoftheperiodictable,anditsatomicnumberisZ=14,thereare14electronsoutsidethenucleus.Theelectronsareoutsidethenucleus,andaresurroundedbylayersfromlowsiliconatomstohighenergylevels,frominsidetooutside.Thisiscalledtheshellstructureofelectrons.Theextranuclearelectronsofsiliconatomshave2electronsinthefirstlayerand8electronsinthesecondlayer,reachingastablestate.The4electronsintheoutermostlayerarevalenceelectrons,whichplayaleadingroleintheconductivityofsiliconatoms.Function.
Becausethesiliconatomhassuchastructure,ithassomespecialproperties:thefouroutermostvalenceelectronsmakethesiliconatominametastablestructure,andthesevalenceelectronsmakethesiliconatomscommunicatewitheachother.Covalentlybonded,duetothestrongcovalentbond,siliconhasahighermeltingpointanddensity;chemicalpropertiesarerelativelystable,itisdifficulttoreactwithothersubstances(excepthydrogenfluorideandlye)atroomtemperature;thereisnoobviousinsiliconcrystalsThefreeelectronscanconductelectricity,buttheconductivityisnotasgoodasthatofmetals,anditincreaseswithtemperature.Ithassemiconductorproperties.
Whenheated,itcanactwithelementalhalogens,nitrogen,carbonandothernon-metals.ItinteractswithcertainmetalssuchasMg,Ca,Fe,Pt,etc.toproducesilicides.Itisinsolubleingeneralinorganicacids,solubleinalkalinesolutions,andreleaseshydrogentoformthecorrespondingalkalimetalsilicatesolution.Underhottemperature,itcaninteractwithwatervapor.
Classification:puresubstance,simplesubstance,non-metallicsimplesubstance.
(1)Reactwithsimplesubstance
(2)ItcanbecombinedwithSomeoxidereactions
(3)Reactionwithacid:onlyreactionwithhydrofluoricacid
(4)Reactionwithalkali
Note:SiliconandaluminumcanbothreactwithacidandAsimplesubstancethatcanreactwithalkalitoreleasehydrogen.
Relatedequation:
Relatedcompounds:
Silica,silicagel,silicate,silicicacid,orthosilicicacid,silane,dichlorideSilane,trichlorosilane,tetrachlorosilane,
Atomicproperties:
Atomicweight:28.0855u;
Nucleuslossmass:0.1455u;
Atomicradius:(calculatedvalue)110(111)pm;
Covalentradius:111pm;
VanderWaalsradius:210pm;
Thearrangementoftheperipheralelectronlayer:3s²3p²;
Thearrangementofelectronsateachenergylevel:2,8,4
Theelectronlayer:KLM;
Oxidizing(oxide):4(amphoteric).
Preparationmethod
Inthelaboratory,magnesiumpowdercanbeusedtoreducethepowderedsilicaunderredheat,andthegeneratedmagnesiumoxideandmagnesiumpowdercanbewashedawaywithdiluteacid,andthenhydrogenisused.Fluoricacidwashesawaytheunactedsilicondioxidetoobtainelementalsilicon.Theamorphoussiliconproducedbythismethodisnotpureenough,whichisbrown-blackpowder.Industrialproductionofsiliconistoreducesilicainanelectricarcfurnace(thecontentofSiO2isgreaterthan99%).Thereducingagentusedispetroleumcokeandcharcoal.WhenusingaDCelectricarcfurnace,allpetroleumcokecanbeusedinsteadofcharcoal.Petroleumcokehaslowashcontent(0.3%to0.8%),andhigh-qualitysilica(SiO2greaterthan99%)canbeusedtodirectlyproducehigh-qualitysiliconforsiliconsteelsheets.High-puritysemiconductorsiliconcanbepreparedbyreducinghigh-puritytrichlorosilaneSiHCl3orSiCl4withhydrogenonahotsiliconrodat1200°C.Ultra-puresinglecrystalsiliconcanbepreparedbytheCzochralskimethodorzonemeltingmethod.
Amorphoussiliconcanbeobtainedbyreducingsilicondioxidewithmagnesium.Crystalsiliconcanbeobtainedbyreducingsilicondioxidewithcarboninanelectricfurnace.Thehigh-puritysiliconusedintheelectronicsindustryismadebyreducingtrichlorosilaneorsilicontetrachloridewithhydrogen.
Applicationareas
1.High-puritysinglecrystalsiliconisanimportantsemiconductormaterial.AsmallamountofgroupIIIAelementisaddedtomonocrystallinesilicontoformap-typesiliconsemiconductor;asmallamountofgroupVAelementisaddedtoformann-typesemiconductor.Thep-typesemiconductorandthen-typesemiconductorarecombinedtoformap-njunction,whichcanbemadeintoasolarcell,whichconvertsradiantenergyintoelectricalenergy.Itisapromisingmaterialinthedevelopmentofenergy.Inaddition,thewidelyuseddiodes,triodes,thyristors,fieldeffecttransistorsandvariousintegratedcircuits(includingchipsandCPUsinpeople'scomputers)areallrawmaterialsmadeofsilicon.
2.Metalceramics,importantmaterialsforastronautics.Ceramicandmetalaremixedandsinteredtomakeametal-ceramiccompositematerial,whichisresistanttohightemperature,richintoughness,andcanbecut.Itnotonlyinheritstherespectiveadvantagesofmetalandceramic,butalsomakesupfortheinherentdefectsofthetwo.Itcanbeusedinthemanufactureofmilitaryweapons.Thefirstspaceshuttle"Columbia"wasabletowithstandthehightemperaturegeneratedbyfrictionwhentravelingthroughdenseatmosphereathighspeed,thankstoitsshellmadeof31,000silicontiles.
3.Opticalfibercommunication,thelatestmodernmeansofcommunication.Puresilicacanbeusedtodrawhigh-transparencyglassfibers.Thelasercanbetransmittedforwardthroughcountlesstotalreflectionsinthepathoftheglassfiber,insteadofbulkycables.Theopticalfibercommunicationcapacityishigh.Aglassfiberasthinasahaircantransmit256telephonesatthesametime;anditisnotaffectedbyelectricityormagnetism,isnotafraidofeavesdropping,andhasahighdegreeofconfidentiality.Opticalfibercommunicationwillrevolutionizehumanlifeinthe21stcentury.
4.Siliconeorganiccompoundswithexcellentperformance.Forexample,siliconeplasticisanexcellentwaterproofcoatingmaterial.Sprayingsiliconeonthewallsofthesubwaycansolvetheproblemofwaterseepageonceandforall.Coatingathinlayerofsiliconeplasticonthesurfaceofancientculturalrelicsandsculpturescanpreventmossfromgrowingandresistwind,rain,andweathering.TheMonumenttothePeople'sHeroesonTiananmenSquareistreatedwithsiliconeplastic,soitwillalwaysbewhiteandfresh.
5.Duetotheuniquestructureoforganicsilicon,itcombinesthepropertiesofinorganicmaterialsandorganicmaterials.Ithasbasicpropertiessuchaslowsurfacetension,lowviscosity-temperaturecoefficient,highcompressibility,andhighgaspermeability.Highandlowtemperature,electricalinsulation,oxidationstability,weatherresistance,flameretardancy,waterrepellency,corrosionresistance,non-toxic,odorless,andphysiologicalinertia.Itiswidelyusedinaerospace,electronicandelectrical,construction,transportation,chemical,textile,Food,lightindustry,medicalandotherindustries,inwhichsiliconeismainlyusedinsealing,bonding,lubrication,coating,surfaceactivity,demoulding,defoaming,foamsuppression,waterproofing,moisture-proof,inertfilling,etc.Withthecontinuousgrowthofthenumberandvarietyofsilicones,theapplicationareascontinuetoexpand,formingauniqueandimportantproductsysteminthefieldofnewchemicalmaterials.Manyvarietiesareirreplaceableandindispensableforotherchemicals.
6.Siliconcanincreasethehardnessofplantstalksandincreasethedifficultyoffeedinganddigestionbypests.Althoughsiliconisnotanessentialelementinplantgrowthanddevelopment,itisalsoachemicalelementnecessaryforplantstoresistadversityandregulatetherelationshipbetweenplantsandotherorganisms.
Siliconplaysagreatroleinimprovingtheresistanceofplantstoabioticandbioticstresses.Forexample,siliconcanimprovetheresistanceofplantstodrought,saltstress,ultravioletradiation,pestsanddiseases.SiliconcanincreasetheresistanceofricetoCnaphalocrocismedinalis.Aftertheapplicationofsilicon,thedefensiveresponseofricetopestfeedingisrapidlyimproved.Siliconplaysaguardroleinplantdefense.
Whenriceisattackedbyinsectpests,siliconcanalertricetoquicklyactivatethejasmonicacidpathwayrelatedtostressresistance.Jasmonicacidsignalinturnpromotestheabsorptionofsilicon.TheinteractionofsiliconandjasmonicacidsignalpathwayaffectsResistanceofricetopests.
Physiologicalfunction
Siliconisoneoftheessentialtraceelementsforthehumanbody.Itaccountsfor0.026%ofbodyweight.Thebiggestharmofsiliconandsilicon-containingdusttothehumanbodyistocausesilicosis.Silicosisisoneoftheseriousoccupationaldiseases.Miners,stoneprocessingworkersandotherworkersinplacescontainingsilicondustshouldtakenecessaryprotectivemeasures.
Siliconisessentialfortheformationofconnectivetissueandcartilage.Siliconcanconnectmucopolysaccharidestoeachotherandbindmucopolysaccharidestoproteinstoformafibrousstructure,therebyincreasingtheelasticityandstrengthofconnectivetissue,Maintaintheintegrityofthestructure;siliconparticipatesinthecalcificationofbonesandplaysaroleintheinitialstageofcalcification.Siliconinfoodcanincreasethespeedofcalcification,especiallywhenthecalciumintakeislow.Theeffectismoreobvious;theaminoacidincollagenisabout21%Itishydroxyproline,prolylhydroxylasemakesprolinehydroxylate,thisenzymeneedssiliconwhenitshowsmaximumactivity;throughanalysisofdifferentsourcesofcollagen,theresultsshowthatsiliconisoneofthecomponentsofcollagen.
Referenceintake:Sincethereisnoexperimentaldataonthehumanbody'ssiliconrequirement,itisdifficulttoputforwardasuitabledailysiliconrequirementofthehumanbody.Accordingtoanimalexperiments,ifsiliconiseasytoabsorb,thedailyrequirementofthehumanbodyItmaybe2～5mg.However,mostofthesiliconinthedietisnoteasilyabsorbed,andtherecommendedintakeisabout5-10mgperday.Itcanbeconsideredthatadailyintakeof20-50mgisappropriate.
Excessivemanifestations:Individualswithhighsilicondisease,highsilicondiet,focalglomerulonephritis,andsignificantlyhighersiliconcontentinkidneytissue.Therearealsoreportsthatalargeamountofmagnesiumsilicate(silicon-containingantacids)mayinduceurinarycalculiinhumans.
Silicosis,long-terminhalationoflargeamountsofsilicon-containingdustthroughtherespiratorytractcancausesilicosis.
Silicosis,alsoknownassilicosis,isthemostcommontypeofpneumoconiosis.Itiscausedbylong-terminhalationofalargeamountofdustcontainingfreesilicondioxide.Itiscausedbyextensivenodularfibrosisinthelungs.Themaindisease.Inpatientswithsilicosis,duetoextensivefibroustissuehyperplasiainbothlungs,themicrovascularcirculationofthelungtissueishinderedandtheresistanceisreduced,soitiseasytomergewithotherdiseases,leadingtoworseningofthediseaseandevendeath.
Insufficientperformance:Thelackofsiliconinthefeedcanslowthegrowthofanimals,andthelackcancausehairandnailstobreakeasily,andtheskinlosesitsluster.Theresultsofanimalexperimentsshowthatsupplementingsiliconwhilefeedingarterioscleroticbeveragesisbeneficialtoprotectthestructureoftheanimal’saorta.Inaddition,ithasbeendeterminedthatthesiliconcontentinbloodvesselwallsisinverselyproportionaltothedegreeofatherosclerosisinhumansandanimals.Amongthepopulationswithdifferentlong-termincidencesofcardiovasculardisease,thesiliconcontentintheirdrinkingwateralsodifferedbyabouttwotimes.Peoplewithhighsiliconcontentindrinkingwatersufferedfewerdiseases.
Siliconisaverysafesubstance.Itdoesnotreactbytheimmunesystem,norisitswallowedbycells,nordoesitbreedbacteriaorreactwithchemicals.Itcanalsotargetskinwounds.Thesilicageldevelopedandproducedcanbeusedtoprotectwounds.Itisaverysafematerialandisapprovedforusebyhealthagenciesinvariouscountries.
Commonrumors
Rumors:Innature,siliconexistsintheformofoxygen-containingcompounds.
Refute:Thereisanaturalsiliconelementinnatureandithasbeenreportedforalongtime.Thefollowingisanexcerptfromtheliteraturereport
Thisarticlehascarriedoutthemineralogy,mineralogyandmineralogyofnaturalsilicon.Studyresearch.Themineralisproducedinaskarn-typesulfurandpolymetallicdepositinacertainplaceinFujian.Naturalsiliconisbrightgrayandsilverywhitewithstrongmetallicluster.Brittle.Underthemicroscope,itwasroundandgranularandmilkydroplets.Homogeneous.Themeasuredspecificgravityd=2.368.HardnessH_M=6.76.ReflectanceR470nm37.08;546nm33.44;589nm31.27;650nm29.96.Afterscanningelectronmicroscopyenergyspectrumanalysisandelectronprobeanalysis,Siis99.87%～99.94%.
