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SiliconWikipedia
Silicon
FromWikipedia,thefreeencyclopedia
SiliconisachemicalelementwithsymbolSiandatomic
number14.Ahardandbrittlecrystallinesolidwithabluegray
metallicluster,itisatetravalentmetalloid.Itisamemberof
group14intheperiodictable,alongwithcarbonaboveitand
germanium,tin,lead,andfleroviumbelow.Itisrather
unreactive,thoughlesssothangermanium,andhasgreat
chemicalaffinityforoxygenassuch,itwasfirstpreparedand
characterizedinpureformonlyin1823byJnsJakob
Berzelius.
Siliconistheeighthmostcommonelementintheuniverseby
mass,butveryrarelyoccursasthepureelementintheEarth's
crust.Itismostwidelydistributedindusts,sands,planetoids,
andplanetsasvariousformsofsilicondioxide(silica)or
silicates.Over90%oftheEarth'scrustiscomposedofsilicate
minerals,makingsiliconthesecondmostabundantelementin
theEarth'scrust(about28%bymass)afteroxygen.[10]
Mostsiliconisusedcommerciallywithoutbeingseparated,and
oftenwithlittleprocessingofthenaturalminerals.Suchuse
includesindustrialconstructionwithclays,silicasand,and
stone.SilicateisusedinPortlandcementformortarandstucco,
andmixedwithsilicasandandgraveltomakeconcretefor
walkways,foundations,androads.Silicatesareusedin
whitewareceramicssuchasporcelain,andintraditionalquartz
basedsodalimeglassandmanyotherspecialtyglasses.Silicon
compoundssuchassiliconcarbideareusedasabrasivesand
componentsofhighstrengthceramics.
Elementalsiliconalsohasalargeimpactonthemodernworld
economy.Mostfreesiliconisusedinthesteelrefining,
aluminiumcasting,andfinechemicalindustries(oftentomake
fumedsilica).Evenmorevisibly,therelativelysmallportionof
veryhighlypurifiedsiliconusedinsemiconductorelectronics(<
10%)isessentialtointegratedcircuitsmostcomputers,cell
phones,andmoderntechnologydependonit.Siliconisthebasis
ofthewidelyusedsyntheticpolymerscalledsilicones.
Siliconisanessentialelementinbiology,althoughonlytiny
tracesarerequiredbyanimals.[11]However,variousseasponges
andmicroorganisms,suchasdiatomsandradiolaria,secrete
skeletalstructuresmadeofsilica.Silicaisdepositedinmany
planttissues,suchasinthebarkandwoodofChrysobalanaceae
andthesilicacellsandsilicifiedtrichomesofCannabissativa,
horsetailsandmanygrasses.[12]
Contents
https://en.wikipedia.org/wiki/Silicon#Siemens_process_and_alternatives
Silicon,14Si
Generalproperties
Name,symbol
silicon,Si
Pronunciation
/slkn/or/slkn/
knorkon
Appearance
crystalline,reflectivewith
bluishtingedfaces
Siliconintheperiodictable
C
Si
Ge
aluminiumsiliconphosphorus
Atomicnumber(Z)
14
Group,block
group14(carbongroup),p
block
Period
period3
Elementcategory
metalloid
28.085[1](28.084
Standardatomic
weight(Ar)
Electron
configuration
28.086)[2]
[Ne]3s23p2
2,8,4
pershell
Physicalproperties
Phase
solid
Meltingpoint
1687K(1414C,2577F)
Boilingpoint
3538K(3265C,5909F)
Densitynearr.t.
2.3290g/cm3
whenliquid,atm.p.
2.57g/cm3
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SiliconWikipedia
Contents
1 Characteristics
1.1 Physical
1.2 Chemical
1.3 Isotopes
2 History
3 Occurrence
4 Production
4.1 Alloys
4.2 Metallurgicalgrade
4.3 Polysilicon
4.3.1 Siemensprocessandalternatives
4.4 Electronicgrade
4.4.1 Earlypurificationtechniques
4.5 Occupationalsafetyandhealth
5 Compounds
6 Applications
6.1 Compounds
6.2 Alloys
6.3 Electronics
6.4 Mechanicalwatches
7 Biologicalrole
8 Seealso
9 References
10 Bibliography
11 Externallinks
Characteristics
Physical
Siliconcrystallizesina
diamondcubiccrystal
structure
Siliconisasolidatroom
temperature,withameltingpoint
of1,414C(2,577F)anda
boilingpointof3,265C
(5,909F).Likewater,ithasa
greaterdensityinaliquidstate
thaninasolidstateanditexpands
whenitfreezes,unlikemostother
substances.Witharelativelyhigh
thermalconductivityof149Wm
1K1,siliconconductsheatwell.
Initscrystallineform,puresilicon
hasagraycolorandametallicluster.Likegermanium,siliconis
ratherstrong,verybrittle,andpronetochipping.Silicon,like
carbonandgermanium,crystallizesinadiamondcubiccrystal
structurewithalatticespacingof0.5430710nm(5.430710
).[13]
https://en.wikipedia.org/wiki/Silicon#Siemens_process_and_alternatives
Heatoffusion
50.21kJ/mol
Heatof
vaporization
383kJ/mol
Molarheat
capacity
19.789J/(molK)
Vaporpressure
P(Pa)
10
100
1k
10k 100k
atT(K) 1908 2102 2339 2636 3021 3537
Atomicproperties
Oxidationstates
4,3,2,1[3]1,2,3,4
(anamphotericoxide)
Electronegativity
Paulingscale:1.90
Ionizationenergies
1st:786.5kJ/mol
2nd:1577.1kJ/mol
3rd:3231.6kJ/mol
(more)
Atomicradius
empirical:111pm
Covalentradius
111pm
VanderWaals
radius
210pm
Miscellanea
Crystalstructure
facecentereddiamondcubic
Speedofsound
thinrod
8433m/s(at20C)
Thermalexpansion
2.6m/(mK)(at25C)
Thermal
conductivity
149W/(mK)
Electrical
resistivity
2.3 103m(at20C)[4]
Bandgap
1.12eV(at300K)
Magneticordering
diamagnetic[5]
Magnetic
susceptibility(mol)
3.9106cm3/mol
Young'smodulus
130188GPa[7]
Shearmodulus
5180GPa[7]
Bulkmodulus
97.6GPa[7]
Poissonratio
0.0640.28[7]
Mohshardness
CASNumber
7440213
(298K)[6]
History
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