Qhov Tseem Ceeb Qhov txawv - Crystal Field Theory vs Ligand Field Theory
Crystal field theory thiab ligand field theory yog ob txoj kev xav hauv inorganic chemistry uas yog siv los piav txog cov qauv kev sib txuas hauv kev hloov pauv hlau. Crystal field theory (CFT) txiav txim siab qhov cuam tshuam ntawm kev cuam tshuam ntawm electron uas muaj d-orbitals thiab lawv cov kev cuam tshuam nrog cov hlau cation thiab, hauv CFT, cov hlau-ligand kev sib cuam tshuam yog suav tias yog electrostatic nkaus xwb. Ligand Field Theory (LFT) txiav txim siab qhov kev sib cuam tshuam ntawm cov hlau-ligand yog covalent kev sib raug zoo thiab nyob ntawm qhov kev taw qhia thiab kev sib tshooj ntawm d-orbitals ntawm cov hlau thiab cov ligand. Qhov no yog qhov sib txawv tseem ceeb ntawm crystal field theory thiab Ligand field theory.
Crystal Field Theory yog dab tsi?
Crystal Field Theory (CFT) tau thov los ntawm tus kws kho mob Hans Bethe hauv xyoo 1929, thiab tom qab ntawd qee qhov kev hloov pauv tau thov los ntawm J. H. Van Vleck hauv xyoo 1935. Qhov kev xav no piav qhia qee yam tseem ceeb ntawm kev hloov pauv hlau complexes xws li magnetism, absorption spectra., oxidation xeev, thiab kev sib koom tes. CFT pib txiav txim siab txog kev sib cuam tshuam ntawm d-orbitals ntawm lub hauv paus atom nrog ligands thiab cov ligands raug suav hais tias yog tus nqi taw tes. Tsis tas li ntawd, qhov attraction ntawm lub hauv paus hlau thiab ligands nyob rau hauv ib qho kev hloov pauv hlau complex yog suav tias yog cov electrostatic nkaus xwb.
Octahedral crystal field stabilization zog
Ligand Field Theory yog dab tsi?
Ligand teb txoj kev xav muab cov lus piav qhia ntxaws ntxiv ntawm kev sib koom ua ke hauv kev sib koom ua ke. Qhov no suav nrog kev sib txuas ntawm cov hlau thiab cov ligand raws li cov ntsiab lus hauv kev sib koom ua ke chemistry. Daim ntawv cog lus no yog suav tias yog kev sib koom ua ke covalent daim ntawv cog lus lossis daim ntawv cog lus dative covalent los qhia tias ob qho tib si electrons hauv daim ntawv cog lus tau los ntawm ligand. Lub hauv paus ntsiab lus ntawm cov siv lead ua teb txoj kev xav yog zoo ib yam li cov nyob rau hauv lub molecular orbital txoj kev xav.
Ligand-Field scheme summarizing σ-bonding in the octahedral complex [Ti(H2O)6]3+.
Qhov txawv ntawm Crystal Field Theory thiab Ligand Field Theory yog dab tsi?
Lub Tswv Yim Tseem Ceeb:
Crystal Field Theory: Raws li qhov kev xav no, kev sib cuam tshuam ntawm kev hloov pauv hlau thiab ligands yog vim qhov kev nyiam ntawm cov nqi tsis zoo ntawm cov hluav taws xob tsis sib txuas ntawm ligand thiab cov hlau cation zoo. Hauv lwm lo lus, kev sib cuam tshuam ntawm cov hlau thiab cov ligands yog cov electrostatic nkaus xwb.
Ligand Field Theory:
- Ib lub orbitals ntawm lub ligand sib tshooj nrog ib lossis ntau lub atomic orbitals ntawm cov hlau.
- Yog hais tias lub orbitals ntawm cov hlau thiab ligand muaj cov energies zoo sib xws thiab sib xws symmetries, muaj kev sib cuam tshuam net.
- Qhov kev sib cuam tshuam tau tshwm sim nyob rau hauv cov txheej txheem tshiab ntawm orbitals, ib qho kev sib raug zoo thiab lwm yam kev tiv thaiv kev sib raug zoo. (Ibqhia tias lub orbital yog tiv thaiv kev sib khi.)
- Thaum tsis muaj kev sib cuam tshuam; Thawj atomic thiab molecular orbitals tsis cuam tshuam, thiab lawv tsis muaj kev cuam tshuam hauv qhov xwm txheej hais txog kev sib cuam tshuam ntawm hlau-ligand.
- Bonding thiab anti-bonding orbitals muaj sigma (σ) lossis pi (π) cim, nyob ntawm kev taw qhia ntawm cov hlau thiab cov ligand.
txwv:
Crystal Field Theory: Crystal field theory muaj ntau yam kev txwv. Nws yuav siv sij hawm rau hauv tus account tsuas yog d-orbitals ntawm lub hauv paus atom; cov s thiab p orbitals tsis suav nrog. Tsis tas li ntawd, qhov kev xav no tsis tau piav qhia vim li cas rau kev sib cais loj thiab qhov me me ntawm qee qhov ligands.
Ligand Field Theory: Ligand teb txoj kev xav tsis muaj kev txwv xws li hauv cov kev tshawb xav siv lead ua teb. Nws tuaj yeem suav tau tias yog qhov txuas ntxiv ntawm cov kev xav siv lead ua teb.
Daim ntawv thov:
Crystal Field Theory: Crystal Field Theory muab kev nkag siab zoo rau cov qauv hluav taws xob ntawm cov hlau hloov pauv hauv cov siv lead ua lattices, Crystal teb txoj kev xav piav qhia txog kev tawg ntawm orbital degeneracy hauv kev hloov pauv hlau vim muaj cov ligands. Nws kuj piav txog lub zog ntawm cov hlau-ligand bonds. Lub zog ntawm lub kaw lus hloov pauv raws li lub zog ntawm cov hlau-ligand bonds, uas yuav ua rau muaj kev hloov pauv hauv cov khoom sib nqus zoo li xim.
Ligand Field Theory: Qhov kev xav no muaj kev txhawj xeeb nrog lub hauv paus chiv keeb thiab qhov tshwm sim ntawm cov hlau- ligand kev sib cuam tshuam los elucidate cov hlau nplaum, kho qhov muag, thiab tshuaj lom neeg ntawm cov tebchaw.
