TEORI MEDAN KRISTAL (CRYSTAL FIELS THEORY).ppt

7/16/2019 TEORI MEDAN KRISTAL (CRYSTAL FIELS THEORY).ppt

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KIMIA ANORGANIK III

CRYSTAL FIELD THEORY

(TEORI MEDAN KRISTAL)



COORDINATE COVALENT

BONDS AND GEOMETRY

Valence Bond Theoryversus

Crystal Field Theory

Valence Bond hybridization

Octahedral d2sp3

Tetrahedral sp3

Square planar dsp2

“low spin” and “high spin” complexes



BENTUK-BENTUK ORBITAL d





The 6 ligands in an octahedral crystal field



Formation of d2sp3 orbitals





Draw the d -orbital splitting diagrams for theoctahedral complex ions of each of thefollowing.

a. Fe2+ (high and low spin)b. Fe3+ (high spin)c. Ni2+

d. Zn 2+

e. Co2+

(high and low spin)

How many unpaired electrons are in thefollowing complex ions?

a. [Ru(NH3)62+

(low-spin case)b. Fe(CN)6

3- (low-spin case)c. Ni(H2O)6

2+

d. V(en)33-

e. CoCl42-



The 4 ligands in a tetrahedral crystal field



Tetrahedral crystal field splitting energy





The d

orbitalenergy

level

diagram

for an

octahedralcomplex



Free Coorbitals



The d

energy

diagrams

for square,planar,

and linear

complexes


http://slidepdf.com/reader/full/teori-medan-kristal-crystal-fiels-theoryppt 15/20Spectra of emerald and ruby



Absorption and emission of light

by Cr (III) complex ions



Spectrochemical Series of Ligands

Wavelength in nm Crystal Fieldof Peak in Spectrum Splitting Energy

Ligand of Co(NH3)4 X * (nm) for Co(NH3)5 X (kJ/mol)COCN- 440 272-NO2

- 458 261en-NC-

NH3 475 252-NCS- 496 241OH2 490 244C2O4

2-

-ONO- 491 244OH- 503 238

-ONO2- 500 239F- 510 235Cl- 533 224-SCN- S2-

Br - 550 217I- 580 206*This wavelength is that at which there is a maximum absorption of light in thes ectrum of the Cobalt III com lex ion.

Pairing

Energy

Large

Small



The complex ion NiCl42- has two unpaired

electrons, while Ni(CN)42- is diamagnetic.

Propose structures for these two complex ions.

Tetrahedral complexes of Co2+ are quite

common. Use a d-orbital splitting diagram to

rationalize the stability of Co2+

tetrahedralcomplex ions.



The compound Ni(H2O)6Cl2 is green, while

Ni(NH3)6Cl2 is purple. Predict the predominant

color of light absorbed by each compound. Which

compound absorbs light with the shorter

wavelength? Predict in which compound is

greater and whether H2O or NH3 is a stronger field

ligand. Do your conclusions agree with thespectrochemical series?



The complex ion Fe(CN)63- is paramagnetic with one

unpaired electron. The complex ion Fe(SCN)63- has

five unpaired electrons. Where does SCN- lie in thespectrochemical series relative to CN-?

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TEORI MEDAN KRISTAL (CRYSTAL FIELS THEORY).ppt