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Questions tagged [crystal-field-theory]

For questions relating to the electronic structure of inorganic complexes, particularly the splitting of degenerate $d$ or $f$ orbitals by the symmetry of the surrounding ligands.

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Splitting of the d$_{xy}$ orbital in square planar transition metal complexes

In square planar complexes, the d$_{x^2-y^2}$ occupies the highest energy level due to it interacting greatest with the ligands. The d$_{z^2}$ orbital is also raised slightly higher in energy than the ...
Ariichu's user avatar
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How to rotate Octahdrals locally along with unit cell axis

I am curious about crystal field effects on a given atom by analysing $m_l$ projected DOS, the individual d-orbitals are given with respect to the Cartesian coordinates (not the lattice constants). So ...
Rajdeep Boral's user avatar
1 vote
2 answers
75 views

Magnetic moment and pairing of electrons in hexaaquairon(III)

I understand that $\ce{H2O}$ acts as a strong ligand for $\ce{Fe^3+},$ $\ce{Cr^3+},$ and $\ce{Co^3+}.$ So, shouldn’t the electrons pair up in the $\mathrm{t_{2g}}$ orbitals? Wouldn’t that cause a ...
nob's user avatar
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Why is Chromium hexacarbonyl diamagnetic?

So there was a question in coordination chemistry regarding the nature of $\ce{[Cr(CO)_6]}$ The book had the question under VBT and solved it using "strong ligands cause all electrons to pair up&...
Aurelius's user avatar
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Why does the nitrito ligand have a higher Δo than water in the spectrochemical series?

I collected some data to determine the value of $\Delta_\text{o}$ for a some transition metal complexes (attached) and I'm very confused as to why $\Delta_\text{o}$ for the $\ce{ONO-}$ ligand is ...
ajk's user avatar
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2 votes
1 answer
140 views

Transition of electrons between t2g and eg to give colour of coordination compounds

In the case of a hexaaquairon (III) complex, the iron (III) ion has 5 electrons, each singly occupying one d orbital. As the d orbitals are occupied, the vacant 4s, 4p and 4d orbitals are hybridised ...
Tabi Khan's user avatar
1 vote
1 answer
85 views

Electronic configuration and symmetry labels of 3d$^7$ ions

In 3d$^7$ ions, e.g. Co$^{2+}$, the ground state is $^4$F, and it contains different levels due to the crystal field, such as $^4T_{1g}$, $^4T_{2g}$ and $^4A_{2g}$. Can anyone tell me what exactly ...
Chris Bohr's user avatar
5 votes
1 answer
155 views

Is concept of weak and strong field ligands applicable in valence bond theory?

I study coordination chemistry at high school. I have read about valence bond theory (VBT) and crystal field theory (CFT) as well. My teacher taught me that VBT is based on the experimental values of ...
InfinityLies's user avatar
-2 votes
1 answer
143 views

Colour of coordination compounds due to d-d transition

Hexaaquanickel(II) is green but tetracyanidonickelate(II) is colourless. On internet I found two explanations. One used valence bond theory that claimed there is no excitation of electron in ...
Harjot Dhillon's user avatar
3 votes
1 answer
62 views

Deriving population of $t_{2g}$ orbitals in transition metal oxides

I have recently studied ligand field theory but there is one thing I do not understand. Consider an octaedral geometry of ligands around a transition metal with a $t_{2g}$ - $e_g$ splitting of atomic $...
Matteo's user avatar
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Color change in coordination compounds

When $\ce{FeCl3}$ is added in water it gives a pale yellow color, but on the addition of $\ce{KSCN}$ it changes to intense red color, so how would we explain the color change? What I thought that the ...
Kutubkhan Bhatiya's user avatar
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29 views

What's the reason of curvature in Tanabe-Sugano diagrams?

Analysing Tanabe-Sugano diagrams it's evident that some of the lines are pretty parallels to that of the ground field whilst others are inclinated or have some curvature. I know what's the effect on ...
Chemistry.'s user avatar
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34 views

Relative magnitude of the crystal field and spin-orbit coupling

In the EPR part of the book 'Physical methods in Inorganic Chemistry' by S. Drago i found that relative magnitudes of crystal field and spin-orbit coupling affect the g values. I understand that the ...
Chemistry.'s user avatar
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251 views

What is the shape of tetraamminenickel(II) complex?

I have basic knowledge of crystal field theory (CFT) and how to predict geometries in complexes with a coordination number of 4. For $\ce{[Ni(NH3)4]^2+}$, we find that the metal center, $\ce{Ni^2+}$, ...
sushant_padha's user avatar
1 vote
1 answer
128 views

Significance of Character tables in d orbital splitting

When we have a molecule say (Co(NH2)6) hypothetically any octahedral molecule it has the point group of Oh and the character table shows the quadratic function such as ($z^2,2z^2-x^2-y^2$) ($xy, xz, ...
Harshdeep Chhabra's user avatar
3 votes
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Energy of d(x²-y²) and d(xy) orbitals the same with respect to trigonal symmetry?

In the orbital splitting diagrams of trigonal planar and trigonal bipyramidal complexes the d$_{x² - y²}$ and d$_{xy}$ orbitals have the same energy. I have always assumed that this is because they ...
Dion Silverman's user avatar
4 votes
1 answer
1k views

Colour properties of nickel complexes

According to Crystal Field theory (CFT), complexes with stronger ligands must absorb light with higher frequency hence would transmit corresponding complementary colour. The colour of $(\ce{[Ni(H2O)2(...
Mithun M R's user avatar
4 votes
1 answer
142 views

Role of spin of electron in splitting of orbitals

What will happen if there are electrons with opposite spins present in the orbitals of ligand and metal atom during the splitting of orbitals in crystal field splitting? Magnetic fields of two ...
Chunks  Drunks's user avatar
-1 votes
1 answer
472 views

Why are electrons paired up in hexaaquacobalt(III)?

I know water is in the middle of the spectrochemical series generally being the differentiator between the weak field and strong field ligands. I have generally seen water being a weak field ligand, ...
Rudransh Sinha's user avatar
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Relationship between d group and $\Delta_O$ value found in Tanabe-Sugano diagram

So this question came up in class recently and got me thinking, is there any relationship between the metal d group and the $\Delta_O$ found for some allowed transition in Tanabe-Sugano diagram? I ...
liuzp's user avatar
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3 votes
1 answer
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Colour of diamagnetic compounds using Crystal Field Theory

I know that the colour in coordination compounds can be explained by CFT in terms of d-d transitions. Are d-d transitions possible in diamagnetic complexes? Why does $\ce{[Co(NH3)6]^3+}$ show colour? ...
Aja's user avatar
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-1 votes
1 answer
338 views

Why does low spin character predominate in hexafluoronickelate(IV)?

According to my book there are no unpaired electrons in $\ce{NiF6^2-}$. However, that should not be the case since fluoride is a weak field ligand. Why does hexafluoronickelate(IV) behave as a low ...
amspsingh04's user avatar
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0 answers
565 views

Ionic radii of transition metal ions in the presence of weak field and strong field ligands

‎‎‎‎‎‎‎‎‎ In the graph given in this image,‎ I was told by my teacher‎ that whenever we start filling the eg orbitals there is an increase in the radius because these orbitals face the ligand directly ...
Beatle's user avatar
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2 votes
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430 views

Why does energy of non-axial d-orbitals decrease in an octahedral complex?

In an octahedral complex, if we assume the metal ion to be inside a cube then ligands will approach from its faces. So the axial d orbitals will experience more electronic repulsion as compared to ...
Nikhil Pundir's user avatar
-2 votes
1 answer
872 views

Do strong field ligands always give d2sp3 hybridisation and weak field ligands give sp3d2 for coordiantion number 6 [closed]

i am actually doing coordination compounds but get confused when it comes to hybridization so wanted to create a short of mine for the exam
Aaryav Gangrade's user avatar
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0 answers
67 views

the ratio between high spin state and low spin state when they coexist

I am considering the spin state's effect on the charge carrier's lifetime, I was told that high spin and low spin state could coexist when the crystal field splitting energy and the pairing energy are ...
Jack's user avatar
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molecular orbital theory and crystal field theory confusions

I am a high school student and I am very confused in Molecular orbital theory, it says that when two orbitals overlaps in the same phase, they form antibonding orbitals and when they overlap in ...
Arun Bhardwaj's user avatar
0 votes
1 answer
148 views

What is electronic configuration of manganese in the manganate(VI) anion?

The electronic configuration of the central atom of $\ce{[MnO4]^2-}$ if given out to be $e^1\,t_2^0$ I want to know how to identify which one of the d-orbitals does this configuration utilizes because ...
Snehal Saurabh's user avatar
11 votes
0 answers
140 views

Using symmetry and group theory arguments to explain iron(II) in a tetrahedral crystal field

I am trying to figure out how to explain $1s \rightarrow 3d$ spectroscopic transitions for $\ce{Fe^{2+}}$ in $T_\mathrm{d}$ symmetry. These transitions make up the pre-edge region in K edge X-ray ...
Silverwilly's user avatar
0 votes
1 answer
252 views

Do "weak-field" and "high spin" complexes refer to the same thing?

I will keep it brief; I know that there are weak field, "moderate" field, and strong field ligands and that these might contribute to a complex being high or low spin overall. My question is,...
kriegersan's user avatar
3 votes
0 answers
144 views

Why is tetrachlorocuprate (II) yellow if it is high-spin?

From my knowledge of transition metal complexes, tetrahedral complexes generally have less splitting (compared to octahedral complexes) because they only involve four ligands are they aren't placed ...
chematwork's user avatar
1 vote
0 answers
544 views

Strength of Pi Donor and Acceptors as Ligands

The spectrochemical series is usually known as the "strength" of the ligands. It makes sense on a basic level as the more willing a ligand is to donating its electrons (via a $\sigma$-bond), ...
chematwork's user avatar
-3 votes
1 answer
5k views

Is acac- a weak field ligand?

From the chemical structure of acac- compared to NH3 and en, is acac- a stronger or weaker ligand strength? How and why do we know this?
Yona Romes's user avatar
6 votes
1 answer
221 views

Tanabe-Sugano diagram x-axis question

While reading up on Tanabe-Sugano diagrams I noticed that many diagrams spread over the internet that all seem to come from this Wikipedia article: https://en.wikipedia.org/wiki/Tanabe–Sugano_diagram. ...
Oscar105's user avatar
1 vote
1 answer
1k views

Why is the pairing energy not considered when calculating the crystal field splitting energy?

Consider the low-spin octahedral crystal field splitting diagram for a d4 system. When we calculate the crystal field splitting energy we simply observe the absorbed color of light and calculate the ...
Eli Jones's user avatar
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0 votes
1 answer
365 views

Which of the following octahedral complexes absorbs the photon with the longest wavelength, λ?

I wonder which of the following absorbs photons with the longest wavelength, $\ce{[Cr(CN)6]^3-}$, $\ce{[Cr(SCN)6]^3-}$ and $\ce{[Cr(H2O)6]^3+}$. I know the one to absorb the highest wavelength should ...
pinkUnicorn999's user avatar
4 votes
2 answers
1k views

Understanding the Jahn–Teller elongation and compression for octahedral complexes (stabilisation/destabilisation of d orbitals)

I am currently learning about Jahn–Teller effect. For elongation I wondered why the d orbitals with $z$ component are stabilised when the metal–ligand bonds are getting longer? I thought a longer bond ...
user avatar
2 votes
0 answers
334 views

Visualizing the e_g and t_2g orbitals in case of tetrahedral crystal field splitting

I am reading about the crystal field theory (CFT) for the case of tetrahedral coordination entities. I understand that the $\mathrm{t_{2g}}$ orbital is nearer to the ligand than the $\mathrm{e_g}$ ...
Paras Khosla's user avatar
-2 votes
1 answer
405 views

Has a low spin tetrahedral Ni(II) complex been synthesised?

How can $\ce{Ni(II)}$ form a low spin tetrahedral compound? I was not able to find such compounds. $\ce{Ni(II)}$ will have $\mathrm {4s^03d^8}$ and tetrahedral needs $\mathrm{sp^3}$. So $2$ electrons ...
Shaurya Goyal's user avatar
1 vote
0 answers
30 views

The quartic electronic state of octahedral Fe(III): How make crystal field splitting diagram?

Using simple arguments from crystal field theory, how do I rationalize the quartic state of octahedral Fe(III)? I am not able to in a logical way distribute the 5 d electrons in such a a way as to end ...
Yoda's user avatar
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2 votes
0 answers
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Parallel between polarisability of donor atom and CFS strength

Observing the strength of crystal field splitting by different ligands, can the following be considered?: Most of the members in the series are ligands where the donor atom is nitrogen, oxygen or ...
Solid - NMR's user avatar
5 votes
1 answer
411 views

Intuitive Explanation for why more negative charge on ligand does not imply more splitting effect?

I have studied coordination chemistry as part of my school curriculum and we covered Crystal Field Theory as our final theory, and the book says that Ligand Field Theory and Molecular Orbital Theory ...
FoundABetterName's user avatar
3 votes
1 answer
302 views

What is the magnetic moment of tris(oxalato)nickelate(IV)?

I'm really struggling with finding the magnetic moment of this complex: In the solutions, it says that it is 2.83 BM (which corresponds to 2 unpaired electrons). However, in drawing out the d orbital ...
MatH's user avatar
  • 131
4 votes
1 answer
800 views

Determination of spinel structure by CFSE

$\ce{CuFe2O4}$ has inverse spinel structure, but $\ce{ZnFe2O4}$ has normal spinel structure. Explain. I know that normal spinels have a structure like $\ce{(A^{II})^{tet}(B^{III})^{oct}_2O_4}$-like ...
DarthAster's user avatar
2 votes
0 answers
126 views

CFSE Calculation

I have $\ce{[ML6]}$ & $\ce{[MD6]}$ as two complexes. I know the $\Delta_0$ & hybridisation of each of them. How do I calculate the CFSE for $\ce{[ML4D2]}$ ? This is my way of thinking : I can ...
ram singh talwar's user avatar
2 votes
0 answers
621 views

Comparing $\ce{PPh3}$ and dppe

The ligands $\ce{PPh3}$ and dppe (dppe = 1,2-Bis(diphenylphosphino)ethane) are both strong field ligands, but is one obviously a stronger field ligand than the other or are they roughly equal? The ...
H.Linkhorn's user avatar
7 votes
1 answer
2k views

What is the shape of [Cr(NO)₄]?

I was learning about crystal field theory recently. I am quite confused about predicting the shape of $\ce{[Cr(NO)4]}$ complex because I am not able to conclude whether it will be square planar or ...
Chem-Learner's user avatar
1 vote
2 answers
1k views

Octahedral Crystal Field Splitting Orbital Degeneracy

How are the $\mathrm{e_g}$ orbitals degenerate with each other? Note: This isn't a homework question. After the semester ended (I don't go to MIT), I ended up on MIT open course-ware to watch some ...
Bob Smith's user avatar
3 votes
1 answer
5k views

Why is the crystal field splitting energy larger for square planar than octahedral complexes?

I recently came across a fact that for the same combination of metal and ligand, the crystal field splitting energy for square planar complexes is larger than that of the corresponding octahedral ...
Chem-Learner's user avatar
0 votes
1 answer
982 views

Octahedral Crystal Field Splitting Orbital Energy Levels [closed]

(image source) In the above diagram, where do the 3/5 and 2/5 come from? Also, how are the $\ce{e_g}$ orbitals degenerate with each other?
Bob Smith's user avatar