Carbon is a nonmetallic chemical element,known by the：碳是一種非金屬化學(xué)元素被稱為

CARBON

Carbonisanonmetallicchemicalelement,knownbythesymbolC.Itisthefundamentalbuildingblockofmaterialinlivingorganismsandisimportanttomanyindustries.Carbonoccursinnatureinnearlypureformindiamondandgraphite.Itisalsothemajorcomponentofcoal,petroleum,asphalt,limestone,andmostmaterialsmadebyplantsandanimals.ThenamecarbonisderivedfromtheLatinwordcarbo,meaningcharcoal,amaterialthatiscomposedprimarilyofcarbon.Acarbonatomcanchemicallycombinewithatomsofotherelements,aswellaswithothercarbonatoms,toformmolecules.Carboncanformmorecompoundsthancananyotherelementexcepthydrogen.Carbonispresentinallsubstancesknownasorganiccompounds.

AtomicNumber:6

Group:14

Period:2

Series:Nonmetals

AtomicStructure

AtomicRadius:0.91

?

AtomicVolume:4.58cm3/

mol

CovalentRadius:0.77

?

CrossSection:

CrystalStructure:Hexagonal

ElectronConfiguration:

1s22s2p2

ElectronsperEnergyLevel:2,4

ShellModel

IonicRadius:

FillingOrbital:2p2

NumberofElectrons(withnocharge):6

NumberofNeutrons(mostcommon/stablenuclide):6

NumberofProtons:6

OxidationStates:4,2

ValenceElectrons:

ElectronDotModel

ChemicalProperties

ElectrochemicalEquivalent:

ElectronWorkFunction:

Electronegativity(Pauling):2.55

HeatofFusion:kJ/mol

Incompatiblities:Verystrongoxidizerssuchasfluorine,chlorinetrifluoride&potassiumperoxide

IonizationPotential

First:11.26

Second:24.383

Third:47.887

ValanceElectronPotential

PhysicalProperties

AtomicMassAverage:12.011

BoilingPoint:5100K4827°C8721°F

Coefficientoflinealthermalexpansion:0.0000021cm/cm/°C(0°C)

Conductivity

Electrical:0.00061106/cm

Thermal:1.29W/cmK

Density:2.26g/cc@300K

Description:Inpureformasdiamondsorgraphite.

ElasticModulus:

Bulk:33/GPa

EnthalpyofFusion:104.6kJ/mole

EnthalpyofVaporization:716.7kJ/mole

FlammablityClass:Combustiblesolid(graphite)

FreezingPoint:seemeltingpoint

HardnessScale

Mohs:0.5

HeatofVaproization:355.8kJ/mol

MeltingPoint:3773

K

3500°

C

6332°

F

MolarVolume:5.34cm3/mole

OpticalReflectivity:27%

OpticalRefractiveIndex:2.417(diamond)

SpecificHeat:0.71J/gK

StateatStandardTemperature(20°C)&Pressure(1atm):Solid

VaporPressure=0mmHg@20°C

Isotopes

Threedifferentisotopesofcarbonexistinnature.Theimportantisotopesofcarbonarecarbon-12,carbon-13,andcarbon-14.Scientistsidentifythembytheirmassnumber.Carbon-12containssixprotonsandsixneutrons,carbon-13containssixprotonsandsevenneutrons,andcarbon-14containssixprotonsandeightneutrons.Innature,carbon-12accountsforabout98.89percentofallcarbon.Carbon-13hasanaturalabundanceof1.11percent,andtheamountofcarbon-14isnegligible.Theatomicmassofcarbonis12.011atomicmassunits(AMU),whichistheaveragemassoftheisotopesofcarbonbasedontheirabundance

Bonding

Carbonatomshavefourouter,orvalence,electronsintheirnextshell.Thisouterelectronshellcanholdeightelectrons.Toobtainafulloutershell,carbonatomsformfourcovalentbondswithotheratoms.Carbonatomscanbondtogetherinchains,rings,andmeshlikenetworks.Ifacarbonatombondswithfouridenticalatoms,thoseatomswillbeequallydistantfromeachother—atthetipsofanimaginarytetrahedron,orapyramidwithatriangularbase.Anytwoofthebondsformanangleof109.5°whencarbonisinatetrahedralform.

Allotropes

Carbonexistsinfourdifferentallotropes.Thethreecommonallotropesofcarbonarediamond,graphite,andamorphouscarbon(examplesofamorphouscarbonincludecharcoal,soot,andthecoal-derivedfuelcalledcoke).graphiterangesfrom1.9to2.3g/cm3,andamorphouscarbonrangesfrom1.8to2.1g/cm3.whilegraphiteisoneofthesoftest.Thesedifferencesinthestructureoftheallotropesarisefromthedifferencesinbondingbetweenthecarbonatoms.

DIAMOND

Indiamond,eachcarbonatombondstetrahedrallytofourothercarbonatomstoformathree-dimensionallattice.Thesharedelectronpairsareheldtightlyinsigmabondsbetweenadjacentatoms.Purediamondisanelectricalinsulator—itdoesnotconductelectriccurrent.Itiscolorlessand,becauseofitshardness,isusedinindustrialcuttingtools.Cutdiamondssparklebrilliantly,whichmakesthemtreasuredgemstonesinjewelry.Thedensityofdiamondis3.5gramspercubiccentimeter(g/cm3),itisoneofthehardestknownmaterials.

WhereFound?

Naturaldiamondsarefoundindepositsthatarebelievedtobetheremainsofancientvolcanicpipes,longtubesofrockymaterialformedbyvolcanoes.Diamond-containingpipesoccurinSouthAfrica,Russia,andthestateofArkansasintheUnitedStates,andintheoceanfloorofftheCapeofGoodHopeinSouthAfrica.Somemeteoritescontainmicroscopicdiamonds.

Thisdiagramshowsthebondingindiamond.

UsesofDiamond

Naturalandsyntheticdiamondscancutnearlyeveryotherknownmaterial.Gemcutters,surgeons,andmanufacturersusediamondknivesanddrills.GeneralElectricCompanyproducedthefirstsyntheticdiamondin1955.Todaytinysyntheticdiamondsarecommonlyusedasabrasives.Producersofmetaltoolsuselaserstoheatcarbondioxideoverametalsurface,makingthecarbonatomscoatthesurfacewithadiamondfilm.Thisdiamondcoatingcanmakecuttingtoolslastmuchlongerthanuntreatedtools.

GRAPHITE

Graphiteisblackandslipperyandconductselectricity.Ingraphite,theatomsformplanar,orflat,layers.Eachlayerismadeupofringscontainingsixcarbonatoms.Theringsarelinkedtoeachotherinastructurethatresemblesthehexagonalmeshofchickenwire.Eachatomhasthreesigmabondsandbelongstothreeneighboringrings.Thefourthelectronofeachatombecomespartofanextensivepibondsystem.Graphiteconductselectricity,becausetheelectronsinthepibondsystemcanmovearoundthroughoutthegraphite.Bondsbetweenatomswithinalayerofgraphitearestrong,buttheforcesbetweenthelayersareweak.Becausethelayerscanslippasteachother,graphiteissoftandcanbeusedasalubricant.Diamondmakerscantransformgraphiteintodiamondbyapplyingextremelyhighpressure(morethan100,000timestheatmosphericpressureatsealevel)andtemperature(about3000°Cor5000°F).Hightemperaturesbreakthestrongbondsingraphitesothattheatomscanrearrangethemselvesintoadiamondlattice.About90percentofthediamondsusedintoolsintheUnitedStatesaremadethisway

Thisdiagramshowsthebondingingraphite

Thisisathreedimensionalpictureofagraphitesurfacewithnodefects.

Anexternalviewofgraphite

PHYSICALCHARACTERISTICSOFGRAPHITE

ChemicalFormula

C

Composition

Carbon,sometimesmixedwithclay

Color

Darkgraytoblack

Streak

Black

Hardness

1-2

CrystalForms

andAggregates

(Hexagonal)Crystalsareuncommon,andareusuallysmall.Theyconsistofthinhexagonalplatesordistortedclustersofflakyplatesinamatrix.Long,wide,hexagonalcrystalsareveryrare.Occursasveins;someverylargeoneshavebeendiscovered.Mostcommonlyoccursinmassiveform.

Transparency

Opaque

SpecificGravity

1.9-2.3

Luster

Metallictodull

Cleavage

1,1-basal

Fracture

Conchoidal

Tenacity

Brittle;thinflakesslightlyflexible

OtherIDMarks

1)Hasagreasyfeel

2)Smudgesthehandswhentouched

3)Isagoodconductorofelectricity(althoughitdoesnotconductheatwell)

OtherNames

BlackLead,Plumbago,Grafito,PencilOre

Polymorphs

Diamond,chaoite,lonsdaleite

InGroup

Nativeelements,nonmetallicelements

AllAbout

Graphiteisrathercommon,butfinecrystalsarerare.MostGraphiteminingareasproduceenormousquantitiesfromasingleorseverallargeveinsthatproduceonlyfewgoodcrystals.

GraphitehasthesamechemicalcompositionasDiamond,butthetwohaveradicallydifferentproperties.

MuchcareshouldbegiventoaGraphitespecimen.Thethincrystals,althoughflexible,areveryfragile,butinelastic.Theywillsmudgeifswipedagainstahardersurface,thusruiningaspecimen.Evenmassivespecimensshouldnotbemovedacrossanyobject,evenpaper,forthespecimenwillwearout.Ifhandled,Graphitesmudgesthehands,andwillsmudgeapaperorcardboardboxifkeptinone.

Uses

The"lead"inpencilsisnotlead,butgraphitemixedwithclay.MuchminedGraphiteisusedaspencilfillings.Itsmainfunction,however,isasalubricant.Ithasmanyelectricaluses,primarilybecauseitistheonlynonmetalthatisagoodconductorofelectricity.Graphiteelectrodesareusedasconsumableconductorsofelectricityintheelectricarcfurnacesteel-makingprocesscommontoallmini-millsteelproducers.Calciumcarbideandderivativeproducts,primarilyacetylene,areusedinthemanufactureofspecialtychemicals,asafuelinmetalcuttingandweldingandformetallurgicalapplicationssuchasironandsteeldesulfurization.

StrikingFeatures

Lowweight,greasyfeel,smudge,andlowhardness

Popularity(1-4)

1

Prevalence(1-3)

1

Demand(1-3)

1

Distinguishing

SimilarMinerals

TherearequiteanumberofmineralssimilarinappearancetoGraphite,butGraphite'sintrinsicpropertieseasilydistinguishit.Molybdenite,commonlyconfusedwithGraphite,isheavierandnotsmudgy.

Commonly

OccursWith

Calcite,Quartz,Muscovite,Biotite(Marble,Limestone)

Noteworthy

Localities

Mostgraphiteisproducedthroughthemetamorphismoforganicmaterialinrocks.Evencoalisoccassionallymetamorphosedintographite.Somegraphiteisfoundinigneousrocksandalsoasnodulesinsideofironmeteorites.Finecrystalsarerare,butsomefamouslocalitiesarePargas,Finland;MountVesuvius,Naples,Italy;Borrowdale,Cumbria,England;andtheFranconquarry,nearMontreal,Quebec.IntheU.S.,commercialdepositsexistinTiconderoga,EssexCo.,NewYork,andinClayCo.,Alabama.GraphiteiscommonatFranklinandOgdensburg,SussexCo.,NewJersey,whereitisfoundassmallflakes,andoccasionallyincrystallizedhexagonalplates.FleckshavealsobeenfoundattheFrenchCreekmine,St.Peters,ChesterCo.,Pennsylvania,andatBisbee,CochiseCo.,Arizona.SmallflakesareabundantintheBearMountainarea,RocklandCo.,NewYork.depositsofgraphitearealsofoundinChina,India,NorthKorea,Mexico,Brazil,theCzechRepublic,andtheUkraine.

AMOPHOUSCARBON

Amorphouscarbonisactuallymadeupoftinycrystal-likebitsofgraphitewithvaryingamountsofotherelements,whichareconsideredimpurities.

In1985chemistscreatedanewallotropeofcarbonbyheatinggraphitetoextremelyhightemperatures.Theynamedtheallotropebuckminsterfullerene,afterAmericanarchitectR.BuckminsterFuller.Unlikediamondandgraphite,whichcanhaveanunendingcrystalstructure,theoriginalfullereneformsmoleculesof60carbonatoms(withamolecularformulaofC60).Themoleculesareshapedliketinysoccerballs(calledbuckyballs),withanatomateachpointwherethelinesonasoccerballwouldnormallymeet.The60carbonatomsbondin20six-memberedringsand12five-memberedrings.Eachcarbonatomisatacornerwheretwosix-memberedringsandonefive-memberedringcometogether.Scientistshavesincediscoveredotherfullerenes,includingverynarrow,longtubesandtheC70fullerene,anelongatedstructureshapedmorelikeafootballbutroundedontheends.Afterscientistsdiscoveredfullerenesinthelab,geologistsdiscoveredfullerenesinnature—inancientrocksinNewZealandandinthemeteorite-createdRiesCraterinGermany.Whencooled,somefullerene-basedcompoundsthatincludeothernoncarbonatomsaresuperconductors,thatis,theycanconductelectricitywithnoresistance.Somepurecarbonfullerenetubesarestrongerthanmetalsandconductelectricity.OthercompoundsbasedonC60appeartoinhibittheactivityofthevirusthatcausesacquiredimmunodeficiencysyndrome(AIDS).

Thefigureshownbelowisfullerenecomposedof60carbons

UsesofCarbon

Scientists,industry,andconsumersusedifferentformsofcarbonandcarbon-containingcompoundsinmanyways.Scientistsusethecarbonatomasthebasicunitofmassandasacluetotheageofanobject.Industriesusecarbontomakesteelfromiron,purifymetals,andaddstrengthtorubber.Intheformofdiamond,carboncancutmostothersubstancesandshinemorebrilliantlyinjewelrythanmostothergems.Carboncompoundscanbeburnedasfueltoheatfoodorhomes,aswellasformmanydifferentmoleculesforallsortsofhumanneeds.Carbonhasmanyindustrialuses.Athightemperatures,carboncombineswithirontomakesteelCarbonsteelwithabout1.5percentcarbonisusedtomakesheetsteelandtools.Steelusedforautomobileandaircraftenginepartscontainsabout1percentcarbon.Highstrengthsteelusedfortransportationequipmentandstructuralbeamscontainsabout0.25percentcarbon.Stainlesssteelforenginepartsorkitchenutensilscontainsfrom0.03to1.2percentcarbon.Carbon,intheformofcoke,canalsoreactwithtinoxideandleadoxidetoyieldthepuremetalstinandlead.Carbonblack,madeoffineparticlesofamorphouscarbon,isproducedbyincompletecombustionofnaturalgas.Itismainlyusedasafillerandreinforcingagentforrubber.Peopleburnfossilfuelstogenerateenergy.Thehigherthe

carboncontent,thegreatertheenergyreleasedincombustion.Carboncompoundsarethebasisofthesyntheticorganicchemicals,whichaccountformanyoftheproductsofthechemicalindustry.Pharmaceuticals,pesticides,paints,andcoatingsareamongtheproductsmadefromsyntheticorganicchemicals.Thesyntheticfiber,syntheticrubber,andplasticsindustriesdependupontheuniqueabilityofcarbontoformstable,longchains,orpolymers,madefromsmallorganicmoleculesbondedtogether.Carbon-basedpolymersformsyntheticfibers,suchasnylon,rayon,andpolyester.Alltheplastics,frompolyethyleneterephthalate(PET)insoftdrinkbottlestopolyvinylchloride(PVC)inwindowframestostyreneincarparts,dependonthepropertiesofcarbon.

OccurrenceOfCarbon

Carboniswidelydistributedinnatureandtheuniverse.ItalsoaboundsintheSun,stars,comets,andintheatmospheresofmostplanets.TheatmosphereofMarsismostlycarbondioxide.ThetotalmassofcarbononEarthisabout7.5×1019kg.Onlyabout0.001percentofthistotalisfoundinlivingplantsandanimals.Carbonisfoundinelementalformasamorphouscarbon(mostlycoal),graphite,anddiamond.LargedepositsofcoalarefoundinEurope,Asia,Australia,andNorthAmerica.Large

Carbonisalsofoundininorganiccompoundsboundupinrocksand,mostimportantlytolivingorganisms,ascarbondioxideintheairandwater.Rockscancontaincarbon-basedinorganiccompoundssuchascarbonatesofcalciumandmagnesium,whichmakeuplimestone.CarbondioxideoccursasagasintheatmosphereofEarthandalsoasadissolvedgasinallnaturalwater.AlthoughthepercentageofcarbondioxideinEarth'satmosphereissmall,ithelpskeeptheplanetwarmenoughtosustainlife.Carbondioxidetrapssomeofthesolarradiation,inthesamewaythatagreenhousetrapsheat.Duringthecarboncycle—thecontinuousexchangeofcarbonamongplants,animals,andtheirenvironment—plantscapturecarbondioxidefromtheair.Withtheaidofsunlight,theplantsusethecarbontobuildcomplexorganicmolecules,suchasstarchesandsugars.Whenanimalseattheplantsortheplantsotherwisedecompose,thecomplexorganicmoleculesarebrokendownagain.Tocompletethecycle,animalsexhalecarbondioxidebackintotheatmosphere.Inaddition,somecarbongetsdepositedinrock,butastherocksweather,theyreleasethecarbon.Carbondioxidealsoescapesthroughtheventsofvolcanoes.Innaturalprocesses,thetotalamountofcarbondioxidereturnedtothe

atmosphereequalstheamountextracted.Plants,animals,andotherlifeformsmakecarbon-basedorganicmoleculesthatrangefromsmalltoenormousinsize.Smallmoleculesincludeaceticacid(C2H4O2),thesimplesugarglucose(C6H12O6),andcommontablesugar,sucrose(C12H22O11).Thethreebasicenergy-providingnutrientsoflivingorganisms,carbohydrates,fats,andproteins,areallbasedoncarbon.Woodfromplantsismadeofaverylargecarbohydrate,calledcellulose.Thehumanbodyisabout18percentcarbonbymass,andthebiologicallysignificantmolecules(otherthanwater)havecarbonaspartorallofthebackboneoftheirstructure.Ribonucleicacids(RNA)anddeoxyribonucleicacids(DNA)aregiganticcarbon-basedmoleculesthatcontainthegeneticinformation,foralivingorganism.Biochemicalprocessesprocessesinvolvethecomplexandcoordinatedmakingorbreakingofcarbonbonds.Fossilfuels,suchascoal,petroleum,andnaturalgas,aremainlymoleculescontainingonlycarbonandhydrogen.Coalisformedfromtheremainsofplantsthatwereburiedandsubjectedtohighpressureandheatoverlongperiodsoftime.Petroleum,formedfrommicroscopicseaplantsandbacteria,isathick,darkliquidcomposedofavarietyofhydrocarbons.Naturalgas,alsoformedfromtinyseacreatures,isusuallyfoundwithpetroleumdeposits.Itconsistsmostlyofmethane,butitalsocontainssignificantamountsofethane,propane,andbutane.Productsmadefrompetroleumincludegasoline,kerosene,jetfuel,dieselfuel,heatingoil,lubricatingoil,andasphalt.

ManufactureandProcessesofCarbon

Likevirtuallyallatoms,carbonatomsaremadeintheinteriorofstarsduringasupermova,anexplosionofastarthatemitsvastamountsofenergy.Byfarthemoststableformofcarbonisgraphite,whichoccursnaturally.TheformofcarbonknownasCarbonblackiscomposedofextremelysmallcrystalsofcarbonhavinganamorphous,orimperfectgraphitestructure.Itisproducedinlargequantitiesbyburningnaturalgas(CH4)orpetroleumhydrocarbonsinalimitedsupplyofairsothatheat“cracks“thehydrocarbon.

CH4(g)C(s)+2H2(g)

Carbonblackisusedinthemanufactureofrubbertiresandasapigmentinblackprintinginks.Cokeisanamorphouscarbonobtainedbyheatingcoalintheabsenceofair.Althoughnaturalgraphiteisessentialforcertainuses,syntheticgraphitemustbemanufacturedtomeetindustrialneeds.Itispreparedbyheatingcokeinanelectricfurnaceto3000oC.Carbonfibersandclotharepreparedbyheatingtextiles,suchasrayon.Atlowtemperatures,atextilepyrolyzes;thatis,itdecomposesintogaseousproductsandsolidcarbon.Athighertemperatures,thecarbonbecomesgraphitized,ortransformedtoamoreorlesscrystallinegraphitestructure.In1955,scientistsatGeneralElectricweresuccessfulinsynthesizingdiamonds.Usingatransition-metalcatalyst,theprocessrequirestemperaturesofabout2000oCandpressuresofabout100,000atmospheres.

Vaporphasecarbon,housedinspeciallydesignedpressurevessels,canbesteamregeneratedon-site.Baseduponaproventechnologydevelopedforthedrycleaningindustry,vaporphasecarboncanbeeconomicallyutilizedforairemissionscontrolofcompoundsthatarereadilyadsorbe