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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Positions of Lowest Energy in CFT Complexes

I know that in a cubic arrangement of ligands around a metal centre (as a precursor step in the formation of a tetrahedral complex), the increase in the energy of the barycentre is lower than when the ...
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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? ...
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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 ...
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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 ...
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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 ...
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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
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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 ...
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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 ...
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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 ...
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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 ...
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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,...
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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 ...
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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), ...
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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?
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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. ...
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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 ...
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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 ...
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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 ...
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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 $\mathrm{e_g}$ ...
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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 ...
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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 ...
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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 ...
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4 votes
1 answer
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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 ...
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1 answer
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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 ...
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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 ...
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2 votes
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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 ...
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2 votes
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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 ...
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7 votes
1 answer
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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 ...
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1 vote
2 answers
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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 ...
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3 votes
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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 ...
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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?
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2 votes
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Crystal field splitting of other orbitals

According to crystal field theory (CFT), $\mathrm{d}$-orbitals of central metal atom splits due to non uniform repulsion of ligands around the metal atom. Why isn't $\mathrm{p}$-orbital splitting ...
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t2g and eg electronic configuration

I have been told that with the help of crystal field theory, we can decide the electronic configuration ($\mathrm{t_{{2g}}}$ $\mathrm{e_g}$ configuration) of the metal ion in a complex. For example, ...
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Geometry of Ni(acac)2

The complex $\ce{Ni(acac)2}$ is paramagnetic as expected , i.e it has two unpaired electrons giving rise to a magnetic moment of $ \sqrt{8}$ BM but doesn't have the tetrahedral geometry consistent ...
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Definition of t2g orbitals in CFT

My textbook defines $\mathrm{t_{2g}}$ orbitals as $\mathrm{t_{2g}}$ stands for a set of three orbitals which are asymmetric with respect to $C_2$ axes, perpendicular to the highest $C_n$ axes, but ...
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Transition metals and their ability to form coloured ions [closed]

I understand that in solution. transition metals form coloured ions, but what about the transition metals in solid compounds that are coloured- is this also due to d-d transition? can you give any ...
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Finding the wavelength of maximum absorption and Crystal Field Splitting of [Ni(H2O)6]2+

(I haven't been here for a long time, so tell me if my formatting is fine) Given The $\ce{[Ni(H2O)6]^2+}$ complex appears green in solution from the transmitted light. Estimate the wavelength of ...
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Why must there be degeneracy in the orbitals to have a Jahn-Teller effect? [closed]

Why is it the case that for Jahn-Teller effects to occur in transition metals there must be degeneracy in either the $\mathrm{t_{2g}}$ or $\mathrm{e_g}$ orbitals?
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What is the order of crystal field stabilisation energy for tris(ethylenediamine)chromium(III) chloride and hexaaquachromium(III) chloride?

In my book it is given that the crystal field stabilisation energy for $\ce{[Cr(en)3]Cl3}$ is more than that of the complex $\ce{[Cr(H2O)6]Cl3}.$ By what I have studied, the crystal field ...
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Sulfate and carbonate ions as ligands

The pentahydrate salt of copper (II) sulfate exists as a blue solid while the anhydrous and monohydrate salts appear as white solids. The structures of these salts are discussed here. The blue colour ...
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1 vote
1 answer
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About Fe(III) and Fe(II) coordination complexes

Why does Fe(III) form octahedral coordination complexes if it has 5 electrons in its d-orbitals? I understand that Fe(II) has 6 electrons in its d-orbitals and 6 lone pairs from 6 ligands as the 12 ...
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1 vote
1 answer
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Magnetic nature of tetraamminedichlorocobalt(III) chloride

I know how to predict magnetic nature when the compound contains only strong field or only weak field ligands. But in $\ce{[Co(NH3)4Cl2]Cl},$ $\ce{NH3}$ is a strong ligand whereas $\ce{Cl-}$ is a weak ...
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What is the hybridization of chromium in chromate and dichromate ions?

I was recently reading about the transition metals and some important compounds of them. I came across a rather interesting diagram in my book... a tetrahedral structure for the chromate ion. The only ...
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Why does the hexachlorocopper(II) ion not form?

I am not entirely sure if this question has been answered before, but I was wondering why when copper forms a complex ion with chlorine there are only 4 chlorine ligands. I asked my teacher and he ...
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Why is Libethenite (Cu2(OH)PO4) color green?

It is not a complex compound and the copper atom is not oxidized so I'm wondering how does its color change. The book mentioned that at favorable conditions, adding water in Copper phosphate, which is ...
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2 votes
2 answers
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Colour of metal complexes with the same type and number of ligands

Crystal Field Theory says that because of d-orbital splitting caused by different ligands we have 2 different energy levels for d-orbitals. It also says that transition metals are coloured because ...
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Why are d(xy),d(yz) and d(xz) orbitals involved in d³s hybridisation?

Shouldn't d(x²-y²) dxy and dz² orbitals participate? Since this corressponds to the best case overlap? What factors decide the participating orbitals in hybridisation? P.S I am well versed with the ...
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10 votes
2 answers
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Why is Ni[(PPh₃)₂Cl₂] tetrahedral?

Since PPh₃ is strong field ligand and, the famous Wilkinson's catalyst, which also possess this ligand is square planar, then what makes the above complex tetrahedral?
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4 votes
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Changing of UV-Vis peak absorption after heating Ni(en)2(NO2)2

(c) The trans-isomer of $\ce{Ni(en)2(NO2)2}$ D is red $(λ_\mathrm{max} = \pu{500 nm}).$ It can be heated to give a new trans-isomer E, which is violet $(λ_\mathrm{max} = \pu{560 nm}).$ Assume that, ...
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Applying Ligand Field Theory, How Can The Color Of Transition Complex Ions Be Explained/Represented?

1. To my understanding, Crystal Field Theory allows for an explanation for the colors of transition metal complex ions due to the d-d transitions which occur. This transition ∆o, is from the t2g ...
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