Qhov Tseem Ceeb Qhov txawv - Hexagonal Close Packing vs Cubic Close Packing
Cov nqe lus Hexagonal kaw packing (HCP) thiab cubic close packing (CCP) yog siv los sau npe ob hom kev npaj hauv tshuaj geometry. Cov ntsiab lus no piav qhia txog kev teeb tsa ntawm atoms, molecules lossis ions hauv lattices (txheej txheem txheej txheem). Thaum piav txog cov kev npaj no, cov khoom tsim los ntawm cov lattice yog hu ua spheres (atoms, molecules lossis ions). Txhawm rau ua kom muaj txiaj ntsig zoo tshaj plaws ntawm kev ntim khoom thiab txo qis qhov chaw khoob hauv lub lattice, cov spheres tau nruj nruj. Cov kev npaj no yog lub npe hu ua cov qauv uas nyob ze tshaj plaws los yog kaw cov khoom sib npaug. Qhov chaw khoob ntawm cov spheres no hu ua qhov. Muaj peb hom qhov; trigonal qhov, tetrahedral qhov thiab octahedral qhov. Lub qhov trigonal yog tsim los ntawm peb lub spheres. Cov duab ntawm lub qhov no zoo li daim duab peb sab. Lub qhov tetrahedral yog tsim thaum ob txheej ntawm spheres muab tso rau ntawm txheej ntawm spheres nyob rau hauv ib txoj kev uas lub trigonal qhov yog them los ntawm ib tug kheej kheej. Lub qhov octahedral yog tsim thaum lub thib ob txheej ntawm spheres muab tso rau ntawm ib txheej ntawm spheres nyob rau hauv xws li ib txoj kev uas lub trigonal qhov yog uncovered. Lub hexagonal kaw packing yog suav tias yog HCP. Qhov kev npaj no muaj ob txheej ntawm spheres hauv ib chav tsev rov ua dua. Lub cubic kaw packing yog suav tias yog CCP. Nws muaj peb txheej ntawm spheres hauv ib chav tsev rov ua dua. Qhov sib txawv tseem ceeb ntawm hexagonal close packing thiab cubic close packing yog tias, chav tsev ntawm hexagonal kaw packing muaj 6 spheres whereas ib chav cell ntawm cubic kaw packing muaj 4 spheres.
Hexagonal Kaw Packing yog dab tsi?
Hexagonal close packing (HCP) yog ib qho kev npaj ntawm spheres nyob rau hauv ib lub lattice; muaj ob txheej ntawm spheres muab tso rau ntawm ib sab, tsim tetrahedral thiab octahedral qhov. Qhov no txhais tau hais tias lub thib ob txheej ntawm spheres yog muab tso rau hauv ib txoj kev uas lub trigonal qhov ntawm thawj txheej yog them los ntawm lub spheres ntawm lub thib ob txheej. Qhov thib peb txheej ntawm spheres zoo li thawj txheej, thiab txheej plaub zoo li txheej thib ob, yog li, cov qauv rov ua dua. Yog li ntawd, chav tsev rov ua dua ntawm hexagonal kaw packing kev npaj yog tsim los ntawm ob txheej ntawm spheres.
Daim duab 01: Hexagonal Close Packing Model
Vim tib lub qauv rov ua dua tom qab txhua ob txheej ntawm spheres, spheres tau ua tiav 74% ntawm qhov ntim ntawm cov lattice. Qhov chaw khoob yog nyob ib ncig ntawm 26%. Txhua tus kheej nyob rau hauv qhov kev npaj no yog surrounded los ntawm 12 nyob sib ze spheres. Thaum cov chaw nruab nrab ntawm 13 spheres (ib thooj + 12 nyob sib ze spheres) tau txiav txim siab, nws muab rau lub pyramid rau sab nrog lub hauv paus hexagonal. Qhov no ua rau lub npe no tus qauv ua hexagonal kaw packing kev npaj. Lub hexagonal kaw packing npaj muaj ib lub qhov loj octahedral ib tug kheej kheej uas yog surrounded los ntawm rau spheres, thiab kuj, rau txhua tus kheej kheej, muaj ob lub tetrahedral qhov nyob ib ncig ntawm plaub spheres.
Cubic Close Packing yog dab tsi?
Cubic close packing (CCP) yog ib qho kev npaj ntawm spheres hauv ib lub lattice; muaj peb txheej ntawm spheres muab tso rau ntawm ib sab, npog tag nrho cov octahedral qhov los ntawm ib tug thib peb txheej ntawm spheres. Lub chav tsev rov ua dua ntawm lub cubic kaw ntim muaj peb txheej ntawm spheres. Kev npaj ntawm thawj txheej thiab txheej thib ob yog zoo ib yam li cov hexagonal kaw packing. Tab sis peb txheej yog muab tso rau hauv ib txoj kev sib txawv kiag li. Nws yog stacked nyob rau hauv lub voids ntawm ob txheej ntawm spheres. Qhov no ua rau npog tag nrho cov octahedral spheres. Yog li ntawd, lub cubic kaw packing npaj tsuas muaj tetrahedral qhov.
Daim duab 02: Kev Sib Piv Ntawm HCP thiab CCP
Lub cubic kaw ntim tau zoo ua kom tiav 74% ntawm cov lattice ntim nrog spheres thiab 26% yog qhov chaw khoob. Txij li thaum rov ua dua chav tsev ntawm lub cubic kaw packing muaj peb txheej ntawm spheres, plaub txheej ntawm spheres zoo li thawj txheej thiab tib cov qauv rov ua dua. Txhua tus kheej nyob rau hauv qhov kev npaj no yog surrounded los ntawm 12 nyob sib ze spheres. Muaj peb hom cubic lattices, raws li kev npaj ntawm spheres thiab qhov;
- Simple cubic (SC)
- Face-centred cubic (FCC)
- Lub cev-centred cubic (BCC)
Lub cubic kaw pacing tuaj yeem pom hauv FCC (lub ntsej muag-centred cubic) kev npaj. Chav tsev cell ntawm lub cubic kaw packing npaj muaj 4 spheres.
Dab tsi zoo sib xws ntawm Hexagonal Close Packing thiab Cubic Close Packing?
- Ob lub Hexagonal Close Packing thiab Cubic Close Packing cov nqe lus piav qhia txog cov spheres thiab qhov (qhov khoob) hauv lattices.
- Ob lub Hexagonal Close Packing thiab Cubic Close Packing npaj muaj spheres muaj 12 tus neeg nyob sib ze.
- Ob qho tib si Hexagonal Kaw Ntim thiab Cubic Kaw Cov Txheej Txheem muaj 74% ntawm cov lattice ntim ntim nrog spheres thiab 26% ntim nrog qhov khoob.
Qhov txawv ntawm Hexagonal Close Packing thiab Cubic Close Packing yog dab tsi?
Hexagonal Kaw Packing vs Cubic Close Packing |
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| Hexagonal kaw packing yog ib qho kev npaj ntawm spheres nyob rau hauv ib tug lattice; muaj ob txheej ntawm spheres tso rau ntawm ib sab, ua tetrahedral thiab octahedral qhov. | Cubic kaw packing yog ib qho kev npaj ntawm spheres nyob rau hauv ib tug lattice; muaj peb txheej ntawm spheres muab tso rau ntawm ib sab, npog tag nrho cov octahedral qhov los ntawm ib tug thib peb txheej ntawm spheres. |
| Hexagonal kaw ntim muaj tetrahedral thiab octahedral qhov. | Cubic kaw packing muaj tetrahedral qhov, tab sis lub octahedral qhov yog them los ntawm ib txheej ntawm spheres. |
| Unit Cell | |
| Chav cell ntawm hexagonal kaw packing muaj 6 spheres. | Chav cell ntawm cubic kaw ntim muaj 4 spheres. |
| Repeating Unit | |
| Qhov rov ua dua ntawm hexagonal kaw ntim muaj ob txheej ntawm spheres. | Qhov rov ua dua ntawm cubic kaw ntim muaj peb txheej ntawm spheres. |
Summary – Hexagonal Close Packing vs Cubic Close Packing
Lub hexagonal thiab cubic kaw packing kev npaj yog siv los piav qhia txog kev npaj ntawm spheres thiab qhov hauv lattices. Qhov txawv ntawm hexagonal close packing thiab cubic close packing yog tias ib lub cell ntawm hexagonal kaw packing muaj 6 spheres whereas ib chav cell ntawm cubic kaw packing muaj 4 spheres.
