Cov khoom muaj zog yog cov uas tuaj yeem tsim lub cev thiab muaj ntim. Lawv txawv ntawm cov kua thiab roj hauv lawv cov duab. Cov khoom khaws cia cov duab ntawm lub cev vim qhov tseeb tias lawv cov khoom tsis tuaj yeem txav tau yooj yim. Lawv txawv ntawm lawv qhov ntom, plasticity, hluav taws xob conductivity thiab xim. Lawv kuj muaj lwm yam khoom. Yog li, piv txwv li, feem ntau ntawm cov khoom no yaj thaum lub sij hawm cua sov, tau txais cov kua hauv lub xeev ntawm kev sib sau. Ib txhia ntawm lawv, thaum rhuab, tam sim ntawd tig mus rau hauv ib tug roj (sublimate). Tab sis kuj muaj cov uas decompose rau hauv lwm yam tshuaj.
Nyob ntawm solids
Tag nrho cov khib nyiab muab faib ua ob pawg.
- Amorphous, nyob rau hauv uas ib tug neeg hais yog teem random. Hauv lwm lo lus: lawv tsis muaj qhov tseeb (txhais tau) qauv. Cov khib nyiab no muaj peev xwm yaj nyob rau hauv ib qho kev ntsuas kub. Feem ntau ntawm cov no suav nrog iav thiab resin.
- Crystalline, uas, dhau los, muab faib ua 4 hom: atomic, molecular, ionic, metallic. Nyob rau hauv lawv, cov hais yog nyob tsuas yog raws li ib tug tej yam qauv, uas yog, nyob rau ntawm lub pob ntawm cov siv lead ua lattice. Nws cov geometry hauv cov khoom sib txawv tuaj yeem sib txawv heev.
Cov khoom siv crystalline muaj zog tshaj cov amorphous hauv lawv tus lej.
Nyob ntawm crystalline solids
Hauv lub xeev, yuav luag txhua yam khoom muaj cov qauv crystalline. Lawv txawv ntawm lawv cov qauv. Crystal lattices nyob rau hauv lawv cov nodes muaj ntau yam hais thiab tshuaj ntsiab. Nws yog raws li lawv tau txais lawv lub npe. Txhua hom muaj cov khoom tshwj xeeb rau nws:
- Nyob rau hauv lub atomic crystal lattice, cov khoom ntawm cov khoom yog khi los ntawm covalent daim ntawv cog lus. Nws stands rau nws durability. Vim li no, xws li tshuaj muaj ib tug siab melting thiab boiling point. Hom no suav nrog quartz thiab pob zeb diamond.
- Nyob rau hauv molecular crystal lattice, kev sib raug zoo ntawm cov khoom yog txawv los ntawm nws qhov tsis muaj zog. Cov khoom ntawm hom no yog cov yam ntxwv ntawm qhov yooj yim ntawm boiling thiab melting. Lawv yog cov volatile, vim hais tias lawv muaj ib yam tsis hnov tsw. Cov khib nyiab no suav nrog dej khov thiab qab zib. Kev txav ntawm cov molecules hauv cov khoom ntawm hom no yog qhov txawv ntawm lawv cov haujlwm.
- Hauv cov ionic siv lead ua lattice ntawm cov nodes, cov khoom sib txuas sib hloov, them nyiaj zoo thiabtsis zoo. Lawv tuav ua ke los ntawm electrostatic attraction. Hom lattice no muaj nyob rau hauv alkalis, ntsev, yooj yim oxides. Ntau yam khoom ntawm hom no yooj yim soluble hauv dej. Vim muaj kev sib raug zoo ntawm cov ions, lawv yog refractory. Yuav luag tag nrho cov ntawm lawv tsis muaj ntxhiab, vim lawv yog cov yam ntxwv los ntawm non-volatility. Cov khoom uas muaj ionic lattice tsis tuaj yeem ua hluav taws xob tam sim no, vim lawv tsis muaj cov hluav taws xob dawb. Ib qho piv txwv ntawm cov khoom ionic yog cov ntsev ntsev. Xws li ib tug siv lead ua lattice ua rau nws nkig. Qhov no yog vim qhov tseeb tias kev hloov pauv hauv nws tuaj yeem ua rau muaj qhov tshwm sim ntawm ion repulsion rog.
- Nyob hauv cov hlau siv lead ua lattice ntawm cov nodes tsuas muaj cov tshuaj ions zoo xwb. Nyob nruab nrab ntawm lawv muaj cov hluav taws xob dawb los ntawm cov thermal thiab hluav taws xob hluav taws xob kis tau zoo. Tias yog vim li cas txhua yam hlau tau txawv los ntawm cov yam ntxwv xws li conductivity.
Cov ntsiab lus dav dav ntawm lub cev nruj
Khoom thiab tshuaj yog xyaum tib yam. Cov ntsiab lus no hais txog ib qho ntawm 4 lub xeev ntawm kev sib sau ua ke. Cov khoom muaj qhov ruaj khov thiab qhov xwm txheej ntawm thermal txav ntawm atoms. Ntxiv mus, tom kawg ua me me oscillations nyob ze ntawm qhov sib npaug ntawm txoj haujlwm. Cov ceg ntawm kev tshawb fawb txog kev kawm txog kev muaj pes tsawg leeg thiab cov qauv sab hauv hu ua solid state physics. Muaj lwm qhov tseem ceeb ntawm kev paub txog cov khoom zoo li no. Qhov kev hloov pauv ntawm cov duab nyob rau sab nraud cuam tshuam thiab txav mus los yog hu ua mechanics ntawm lub cev deformable.
Vim cov khoom sib txawv ntawm cov khib nyiab, lawv tau pom daim ntawv thov hauv ntau yam khoom siv tsim los ntawm tus txiv neej. Feem ntau, lawv siv raws li cov khoom xws li hardness, ntim, loj, elasticity, plasticity, fragility. Kev tshawb fawb niaj hnub tso cai siv lwm yam zoo ntawm cov khib nyiab uas tuaj yeem pom hauv chav kuaj xwb.
Dab tsi yog crystals
Crystals yog lub cev muaj zog nrog cov khoom sib xyaw ua ke hauv ib qho kev txiav txim. Txhua yam tshuaj muaj nws tus kheej qauv. Nws cov atoms tsim muaj peb-dimensionally periodic kev npaj hu ua crystal lattice. Cov khoom muaj qhov sib txawv ntawm cov qauv symmetries. Lub xeev crystalline ntawm cov khoom yog suav tias yog qhov ruaj khov vim tias nws muaj qhov tsawg kawg nkaus ntawm lub zog muaj peev xwm.
Feem ntau ntawm cov khoom siv (natural) muaj ntau tus neeg cov nplej (crystallites). Cov tshuaj no hu ua polycrystalline. Cov no suav nrog kev siv hlau thiab hlau, nrog rau ntau pob zeb. Monocrystalline yog hais txog ib qho ntuj lossis hluavtaws siv lead ua.
Feem ntau, cov khib nyiab no yog tsim los ntawm lub xeev ntawm cov kua theem, sawv cev los ntawm yaj lossis kua. Qee zaum lawv tau txais los ntawm lub xeev gaseous. Cov txheej txheem no hu ua crystallization. Ua tsaug rau kev tshawb fawb thiab thev naus laus zis, cov txheej txheem rau kev loj hlob (synthesis) ntawm ntau yam khoom tau nce qib kev lag luam. Feem ntau cov muaju muaj lub ntuj tsim nyob rau hauv daim ntawv ntawm tsis tu ncuapolyhedra. Lawv qhov ntau thiab tsawg sib txawv heev. Yog li, ntuj quartz (pob zeb siv lead ua) tuaj yeem hnyav txog ntau pua kilograms, thiab pob zeb diamond - txog li ob peb grams.
Nyob rau hauv amorphous solids, atoms nyob rau hauv tas li oscillation nyob ib ncig ntawm random nyob rau hauv cov ntsiab lus. Lawv khaws ib qho kev txiav txim luv luv, tab sis tsis muaj kev txiav txim ntev ntev. Qhov no yog vim qhov tseeb tias lawv cov molecules nyob ntawm qhov deb uas tuaj yeem sib piv nrog lawv qhov loj me. Cov piv txwv feem ntau ntawm cov khoom zoo li no hauv peb lub neej yog lub xeev iav. Cov tshuaj amorphous feem ntau suav hais tias yog cov kua uas muaj viscosity siab infinitely. Lub sijhawm ntawm lawv cov crystallization yog qee zaum ntev heev uas nws tsis tshwm sim.
Nws yog cov khoom saum toj no ntawm cov tshuaj no uas ua rau lawv tshwj xeeb. Amorphous solids raug suav hais tias tsis ruaj khov vim lawv tuaj yeem ua crystalline dhau sijhawm.
Cov molecules thiab atoms uas ua rau cov khoom yog ntim ntawm qhov ntom ntom. Lawv xyaum tuav lawv txoj kev sib nrig sib txheeb ze rau lwm cov khoom thiab tau tuav ua ke vim kev sib cuam tshuam ntawm intermolecular. Qhov kev ncua deb ntawm cov molecules ntawm cov khoom sib txawv yog hu ua lattice parameter. Cov qauv ntawm cov teeb meem thiab nws symmetry txiav txim siab ntau yam khoom, xws li electron band, cleavage, thiab optics. Thaum lub zog loj txaus siv rau cov khoom, cov khoom zoo no tuaj yeem ua txhaum rau ib qib lossis lwm qhov. Nyob rau hauv rooj plaub no, lub cev muaj zog yuav raug deformation mus tas li.
Atoms ntawm cov khib nyiab ua oscillatory motions, uas txiav txim siab lawv muaj thermal zog. Txij li thaum lawv tsis tsim nyog, lawv tsuas tuaj yeem pom nyob rau hauv lub chaw kuaj mob. Cov qauv molecular ntawm cov khoom muaj feem cuam tshuam rau nws cov khoom.
Study of solids
Ntawm, cov khoom ntawm cov tshuaj no, lawv qhov zoo thiab kev txav ntawm cov khoom yog kawm los ntawm ntau ntu ntawm cov khoom hauv lub xeev physics.
Rau txoj kev tshawb fawb yog siv: xov tooj cuaspectroscopy, kev tsom xam cov qauv siv x-rays thiab lwm txoj kev. Qhov no yog li cas cov neeg kho tshuab, lub cev thiab thermal zog ntawm cov khib nyiab tau kawm. Hardness, load kuj, tensile zog, theem transformations yog kawm los ntawm cov ntaub ntawv science. Nws feem ntau echoes solid state physics. Muaj lwm yam kev tshawb fawb tseem ceeb niaj hnub no. Kev kawm txog cov uas twb muaj lawm thiab kev sib txuas ntawm cov khoom tshiab yog ua los ntawm cov khoom hauv lub xeev chemistry.
Txoj kev sib tw
Qhov xwm ntawm qhov txav ntawm sab nraud ntawm cov khoom siv hluav taws xob ntawm cov khoom siv txiav txim siab ntau ntawm nws cov khoom, piv txwv li, hluav taws xob. Muaj 5 chav kawm ntawm lub cev zoo li no. Lawv tau teeb tsa nyob ntawm hom atomic daim ntawv cog lus:
- Ionic, tus yam ntxwv tseem ceeb uas yog lub zog ntawm electrostatic attraction. Nws nta: kev xav thiab nqus ntawm lub teeb hauv thaj tsam infrared. Thaum tsis tshua muaj kub, cov ionic daim ntawv cog lus yog tus yam ntxwv ntawm cov hluav taws xob conductivity tsawg. Ib qho piv txwv ntawm cov khoom no yog sodium ntsev ntawm hydrochloric acid (NaCl).
- Covalent,nqa los ntawm ib khub electron uas belongs rau ob lub atoms. Xws li daim ntawv cog lus tau muab faib ua: ib zaug (yooj yim), ob npaug thiab triple. Cov npe no qhia tias muaj cov khub ntawm electrons (1, 2, 3). Ob npaug thiab triple bonds yog hu ua ntau daim ntawv cog lus. Muaj lwm qhov kev faib ntawm pab pawg no. Yog li, nyob ntawm qhov sib faib ntawm electron ceev, polar thiab non-polar bonds txawv. Thawj yog tsim los ntawm txawv atoms, thiab qhov thib ob yog tib yam. Xws li lub xeev muaj teeb meem, piv txwv ntawm cov pob zeb diamond (C) thiab silicon (Si), yog qhov txawv ntawm nws qhov ntom. Cov crystals nyuaj tshaj plaws yog tshwj xeeb rau covalent daim ntawv cog lus.
- Hlau, tsim los ntawm kev sib txuas cov valence electrons ntawm atoms. Yog li ntawd, ib qho huab huab electron tshwm sim, uas tau hloov pauv raws li qhov cuam tshuam ntawm hluav taws xob hluav taws xob. Ib daim ntawv cog lus hlau yog tsim thaum cov atoms loj heev. Lawv muaj peev xwm pub dawb electrons. Nyob rau hauv ntau cov hlau thiab complex compounds, daim ntawv cog lus no tsim ib lub xeev ntawm cov teeb meem. Piv txwv li: sodium, barium, txhuas, tooj liab, kub. Ntawm cov khoom tsis yog xim hlau, cov hauv qab no tuaj yeem sau tseg: AlCr2, Ca2Cu, Cu5. Zn8. Cov khoom uas muaj cov hlau nplaum (hlau) muaj ntau yam hauv lawv lub cev. Lawv tuaj yeem ua kua (Hg), mos (Na, K), tawv heev (W, Nb).
- Molecular, tshwm sim hauv cov muaju, uas yog tsim los ntawm tus kheej molecules ntawm ib yam khoom. Nws yog tus cwj pwm los ntawm qhov sib txawv ntawm cov molecules nrog xoom electron ceev. Lub zog uas khi atoms hauv cov muaju yog qhov tseem ceeb. Cov molecules yog attractedrau ib leeg tsuas yog qaug zog intermolecular attraction. Yog li ntawd, cov kev sib raug zoo ntawm lawv tau yooj yim puas thaum cua sov. Cov kev sib txuas ntawm atoms yog qhov nyuaj dua rau kev tawg. Molecular bonding yog subdivided rau orientational, dispersion thiab inductive. Ib qho piv txwv ntawm cov khoom no yog cov khoom muaj methane.
- Hydrogen, uas tshwm sim ntawm qhov zoo polarized atoms ntawm ib lub molecule los yog nws ib feem thiab qhov tsawg tshaj plaws tsis zoo polarized particle ntawm lwm molecule los yog lwm yam. Cov ntawv cog lus no suav nrog dej khov.
Txoj khoom ntawm cov khoom khib nyiab
Hnub no peb paub dab tsi? Cov kws tshawb fawb tau kawm ntev txog cov khoom ntawm lub xeev ntawm cov teeb meem. Thaum raug kub, nws kuj hloov. Kev hloov ntawm lub cev mus rau hauv cov kua yog hu ua melting. Kev hloov pauv ntawm cov khoom mus rau hauv lub xeev gaseous hu ua sublimation. Thaum qhov kub thiab txias qis, crystallization ntawm cov khoom tshwm sim. Qee cov tshuaj nyob rau hauv kev cuam tshuam ntawm txias dhau mus rau theem amorphous. Cov kws tshawb fawb hu cov txheej txheem no vitrification.
Thaum lub sijhawm hloov pauv, cov qauv sab hauv ntawm cov khoom hloov pauv. Nws tau txais qhov kev txiav txim loj tshaj plaws nrog txo qhov kub thiab txias. Ntawm atmospheric siab thiab kub T > 0 K, tej yam khoom uas muaj nyob rau hauv cov xwm solidify. Tsuas yog helium, uas yuav tsum muaj lub siab ntawm 24 atm kom crystallize, yog qhov zam rau txoj cai no.
Lub xeev muaj teeb meem muab nws ntau yam khoom ntawm lub cev. Lawv ua tus cwj pwm tshwj xeeb ntawm lub cevnyob rau hauv kev cuam tshuam ntawm tej yam teb thiab lub zog. Cov khoom no tau muab faib ua pawg. Muaj 3 txoj kev raug, sib xws rau 3 hom hluav taws xob (mechanical, thermal, electromagnetic). Raws li, muaj 3 pawg ntawm lub cev ntawm cov khoom khib nyiab:
- Cov khoom siv kho tshuab cuam tshuam nrog kev ntxhov siab thiab lub cev hnyav. Raws li cov qauv no, cov khib nyiab tau muab faib ua elastic, rheological, lub zog thiab thev naus laus zis. Thaum so, xws li lub cev khaws nws cov duab, tab sis nws tuaj yeem hloov pauv raws li qhov kev txiav txim ntawm lub zog sab nraud. Nyob rau tib lub sijhawm, nws qhov deformation tuaj yeem yog cov yas (thawj daim ntawv tsis rov qab), elastic (rov qab los rau nws daim ntawv qub) lossis kev puas tsuaj (thaum muaj qee qhov pib mus txog, lwj / tawg tshwm sim). Cov lus teb rau kev siv quab yuam yog piav qhia los ntawm moduli ntawm elasticity. Lub cev muaj zog tiv tsis tau tsuas yog compression, ncab, tab sis kuj hloov, torsion thiab khoov. Lub zog ntawm lub cev muaj zog yog nws cov cuab yeej tiv thaiv kev puas tsuaj.
- Thermal, tshwm sim thaum raug tshav kub. Ib qho ntawm cov khoom tseem ceeb tshaj plaws yog lub melting point uas lub cev nkag mus rau hauv lub xeev ua kua. Nws yog pom nyob rau hauv crystalline solids. Amorphous lub cev muaj lub latent cua sov ntawm fusion, txij li thaum lawv hloov mus rau lub xeev ua kua nrog nce kub tshwm sim maj mam. Thaum ncav cuag ib qho cua sov, lub cev amorphous poob nws elasticity thiab tau txais plasticity. Lub xeev no txhais tau hais tias nws tau mus txog lub iav hloov pauv kub. Thaum rhuab, qhov deformation ntawm cov khoom tshwm sim. Thiab feem ntau nws nthuav. Quantitatively qhov nolub xeev yog characterized los ntawm ib co coefficient. Lub cev kub cuam tshuam rau cov khoom siv xws li fluidity, ductility, hardness thiab lub zog.
- Electromagnetic, cuam tshuam nrog kev cuam tshuam ntawm cov khoom ntawm cov khoom ntws ntawm microparticles thiab electromagnetic nthwv dej ntawm siab rigidity. Cov khoom hluav taws xob kuj tseem raug xa mus rau lawv.
Zone structure
Solids kuj raug cais raws li lub npe hu ua band. Yog li, ntawm lawv lawv qhov txawv:
- Tus neeg coj, tus yam ntxwv ntawm lawv qhov kev coj ua thiab kev sib tw valence sib tshooj. Hauv qhov no, cov khoom siv hluav taws xob tuaj yeem txav nruab nrab ntawm lawv, tau txais lub zog me ntsis. Tag nrho cov hlau yog conductors. Thaum qhov sib txawv muaj peev xwm siv rau lub cev zoo li no, ib qho hluav taws xob tam sim no raug tsim (vim lub zog dawb ntawm cov hluav taws xob ntawm cov ntsiab lus nrog qhov qis tshaj plaws thiab muaj peev xwm siab tshaj plaws).
- Dielectrics uas nws thaj chaw tsis sib tshooj. Lub sijhawm nruab nrab ntawm lawv tshaj 4 eV. Yuav tsum muaj ntau lub zog los ua cov khoom siv hluav taws xob los ntawm lub valence mus rau qhov conduction band. Vim cov khoom no, dielectrics xyaum tsis ua tam sim no.
- Semiconductors yam ntxwv los ntawm qhov tsis muaj conduction thiab valence bands. Lub sijhawm nruab nrab ntawm lawv yog tsawg dua 4 eV. Txhawm rau hloov cov khoom siv hluav taws xob los ntawm qhov valence mus rau cov khoom siv hluav taws xob, lub zog tsawg dua yuav tsum tau siv rau dielectrics. Ntshiab (tsis muaj thiab haiv neeg) semiconductors tsis dhau tam sim no zoo.
Kev txav ntawm cov molecules hauv cov khib nyiab txiav txim siab lawv cov khoom siv hluav taws xob.
Lwm yamkhoom
Lub cev muaj zog kuj tau faib ua raws li lawv cov khoom sib nqus. Muaj peb pawg:
- Diamagnets, cov khoom ntawm uas nyob ntawm me ntsis ntawm qhov kub thiab txias lossis lub xeev ntawm kev sib sau.
- Paramagnets tshwm sim los ntawm kev taw qhia ntawm cov hluav taws xob hluav taws xob thiab lub sijhawm sib nqus ntawm atoms. Raws li Curie txoj cai, lawv susceptibility txo nyob rau hauv feem rau qhov kub thiab txias. Yog li, ntawm 300 K nws yog 10-5.
- Lub cev nrog cov qauv sib nqus xaj, nrog rau qhov kev txiav txim ntev ntawm atoms. Nyob rau ntawm cov pob txha ntawm lawv cov lattice, cov khoom uas muaj lub sij hawm sib nqus tau nyob ib ntus. Cov khoom khib nyiab thiab cov khoom no feem ntau yog siv rau ntau yam kev ua haujlwm ntawm tib neeg.
Cov tshuaj nyuaj tshaj plaws hauv cov xwm txheej
Lawv yog dab tsi? Qhov ntom ntawm cov khib nyiab feem ntau txiav txim siab lawv hardness. Nyob rau hauv xyoo tas los no, cov kws tshawb fawb tau tshawb pom ntau yam ntaub ntawv uas lees tias yog "lub cev ruaj khov tshaj plaws." Cov khoom siv nyuaj tshaj plaws yog fullerite (ib qho siv lead ua nrog fullerene molecules), uas yog li 1.5 npaug ntawm cov pob zeb diamond. Hmoov tsis zoo, tam sim no tsuas yog muaj nyob rau hauv cov khoom me me xwb.
Hnub no, cov khoom hnyav tshaj plaws uas yuav siv tau rau yav tom ntej hauv kev lag luam yog lonsdaleite (hexagonal pob zeb diamond). Nws yog 58% nyuaj dua pob zeb diamond. Lonsdaleite yog ib qho kev hloov kho allotropic ntawm carbon. Nws siv lead ua lattice zoo ib yam li pob zeb diamond. Ib lub cell lonsdaleite muaj 4 atoms, thaum lub pob zeb diamond muaj 8. Ntawm cov siv lead ua siv dav, pob zeb diamond tseem nyuaj tshaj hnub no.
