Questions tagged [coordination-compounds]

This tag is for questions concerning coordination compounds including but not limited to ligand properties, metal properties, orbital splitting, micro- and macroscopic properties of entire complexes etc. For complexes where carbon monoxide is the only ligand, use the [carbonyl-complexes] tag instead. For organic catalysts or proteins, the tag is applicable if the question is about the metal’s direct coordination sphere.

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Products formed on reaction of aqueous solution of iron(III) nitrate nonahydrate

Crystalline iron(III) nitrate nonahydrate, Fe(NO3)3.9H2O, has a very pale violet color. When added to water, the crystals dissolve to form a brown solution. Treatment of this brown solution with ...
Priyanshu Kumar's user avatar
2 votes
2 answers
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Why wont Al(OH)3 form in this reaction?

I am in grade 11. We were learning qualitative salt analysis and my teacher wrote a reaction on board - $$\ce{Al^3+ +H2O\rightarrow[Al(H2O)6]^3+}.$$ Now as far as structure of the complex is concerned ...
Aleph's user avatar
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Why does the answer given consider octahedral splitting even though there is no specification of the complex

My textbook (NCERT Chemistry Part 1) gives this question as an example: Why is $\ce{Cr^2+}$ reducing and $\ce{Mn^3+}$ oxidising when both have $d^4$ configuration? And the solution given along with ...
Harshul's user avatar
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Why do most sulphate salts have water of crystallization in them?

I mean looking at most of the sulphate salts (there are so many but just to name some Epsom salt, blue vitirol, gypsum...) they have some amount of water crystallized within them (Epsom salt is MgSO4....
Cuckoo Beats's user avatar
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Is concept of Weak and Strong Field Ligands applicable in Valence Bond Theory?

I am high school student studying Coordination- Chemistry. I have read about Valence bond theory and Crystal Field Theory as well. My teacher taught me that Valence bond theory is based on ...
InfinityLies's user avatar
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Number of Isomers in this Square Planar Metal Complex (Does arrangement in square planar matters)?

I tried to work this out: I understood that $NO_2$ and SCN are ambidentate ligands and they can be attached differently which was what I tried. I only could find and draw out 8 isomers, but there are ...
DocManIM's user avatar
3 votes
1 answer
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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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Bond length in square planar coordination complex of Platinum

(Q): Select the correct statements for $[Pt(NH_3)_2Cl_2]$ : (a): Geometrical Isomerism (b): Optical Isomerism (c): All bond length are equal. (d): Chelation effect is effect. (e): Hydrogen bonding is ...
Ahmad Raza Beg's user avatar
2 votes
3 answers
194 views

How to calculate the pH of a solution with addition of a complex

The scenario is this. I have $50$ mL of $0.1$ M $\ce{NH4^+}$ at a certain temperature which gives it a $K_a=5.2\times 10^{-8}$. To this solution, I add $0.02$ moles of $\ce{Cd(NO_3)_2}$. It is known ...
Pen and Paper's user avatar
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Isomers of Pentaaminechlorocobalt(III) chloride

What kind of isomers does $\ce{[Co(NH3)5Cl]Cl2}$ exhibit? I can rule out geometrical and optical due to there being $\ce{5 NH3}$ ligands which central metal atom cannot have different positions of $\...
Razz's user avatar
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Color of coordination compounds

My book(Page $259$ section $9.5.5$) says that the color mainly comes from absorption of light in the coordination compound: The color is complementary of the wavelength it absorbs , the wavelength ...
Razz's user avatar
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Reason behind paramagnetic substances having color

I've read in many books that paramagnetic substances are coloured while diamagnetic substances are colourless (yes there are some exceptions too). But nowhere i could find a reason for this phenomenon....
Gnanadeep Sai's user avatar
3 votes
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What prevents an octahedral complex from always assuming the quadratic planar limiting case, due to the Jahn–Teller distortion?

When a given high-spin complex is Jahn–Teller distorted, this does not change the relative position of the total energy of the complex (assuming $\mathrm{d^{10}}$ configuration). Indeed, the ...
Rivinius's user avatar
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2 answers
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What does the 2 in t2g stand for?

I have read so far that it is about whether the d-Orbital is symmetric to a C2 element perpendicular to its main rotational axis. If all the given orbitals in a group are symmetric to that element, ...
Rivinius's user avatar
1 vote
1 answer
224 views

Which is better ligand, PH3 or PF3?

It confuses me that many researches pointed out different results about phosphine ligands properties (σ-donor and π-acceptor). Since both phosphine $\ce{PH3}$ and phosphorus trifluoride $\ce{PF3}$ ...
Shira's user avatar
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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
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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
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1 answer
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How to find the ligand field splitting of d orbitals in a square planar complex?

I am working with a Iron square planar complex with $\ce{NH2-}$ and $\ce{OH-}$ ligands having cis and trans conformation. My question is how to theoretically/computationally calculate the ligand filed ...
Harshdeep Chhabra's user avatar
6 votes
1 answer
360 views

Why is there no neutral [Cr(OC)6] or anionic [Fe(NC)6] - isomers of cyanide and carbonyl complexes?

I was just reading about linkage isomerism, that usually arise due to the fact that some ligands are ambidentate (i.e. $\ce{SCN}$ and $\ce{NCS}$). I then think to myself, considering only the ligand ...
Tensor's user avatar
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1 answer
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Do transition metals only carry d-electrons as valence electrons until group 11?

as I was revisiting my lecture notes in inorganic chemistry, I noticed that we treated the transition metals as elements where the energetic order of 4s ad 3d orbitals is reversed. For example ...
Mäßige's user avatar
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-4 votes
2 answers
87 views

Mechanism of S2Cl2 and NaHSO3 [closed]

I learned that NaHSO3 reacts with S2Cl2 to give Na2S4O6 as product. After looking up the structure of Na2S4O6, it confuses me that four sulfur atoms connect together. I couldn't figure out the exact ...
Shira's user avatar
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Crown ether complex formation with cesium carbonate

I am searching for some papers which form complex between crown ether and caesium carbonate. But Most papers only use caesium carbonate as a base in the synthesis of crown ether, not ionic compound ...
Krang Lee's user avatar
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Do complexes of a metal distribute in between the water and an organic compound layer?

My original question is one that is stated in the title, and I also have some side questions too. I came across this question where you have a CuSO4 aqueous solution. Then you take an Ammonia aqueous ...
donthababakka's user avatar
3 votes
0 answers
58 views

Is aqua-meth-myoglobin (Fe3+) paramagnetic?

Is aqua-meth-myoglobin (Fe3+) paramagnetic? In this case, the iron has all 6 coordination positions occupied by ligands: 4 nitrogen atoms from the pyrrolic rings that compose the porphyrin, 1 ...
Arthur.chem's user avatar
-2 votes
1 answer
150 views

How does an equilibrium move when increasing the concentration of water?

I have the following equilibrium given: $$\ce{[Co(H2O)6]^2+(aq) + 4 Cl-(aq) <=> [CoCl4]^2-(aq) + 6 H2O(l)}$$ (I imagine the (l) for water is wrong, as the water is a part of the solution) The $\...
Rekeren1's user avatar
3 votes
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60 views

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
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Why is the distinction from "coordinative bond" useful at all? [closed]

There are 3 types of coordinative bonding, complex formation at the electron donor, complex formation at the electron donor acceptor and complex formation at the electron acceptor, so what is the ...
iwab's user avatar
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What is the actual complex formed in Fehling's solution?

What is the actual complex formed in Fehling's solution when Fehling’s solution A and Fehling’s solution B are mixed in equal amount? Wikipedia suggests: $\ce{[Cu(C4H4O6)2]^2-}$ But the book I follow ...
CHEMUMAN's user avatar
-4 votes
1 answer
64 views

Are zinc & copper extracted from its ore using cyanide salt?

In my textbook, the extraction of Zinc is done from $\ce{ZnS}$ and copper from Cuprous oxide, so neither of extracting procedures involve the use of $\ce{CN^-}$ salts. Thinking further, both Zn(II) ...
I.Bedi's user avatar
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2 answers
279 views

Can Acetone act as a ligand?

I have never seen any Carbonyl Oxygen acting as a ligand. But a naive intution says that since carbonyl oxygen has two lone pairs, it should act as a donor atom, donating one of its lone pairs as ...
CHEMUMAN's user avatar
1 vote
0 answers
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Spin-only magnetic moment of a coordination complex

While finding the spin-only magnetic moment of a coordination complex, we count the number of unpaired electrons on the central metal atom. What about unpaired electrons on the ligand? Say in the case ...
wonderer's user avatar
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0 answers
113 views

Theoretical explanation for: Why is KMnO4 stronger oxidizing agent than K2Cr2O7?

I know that it can be explained using the Reduction Potential values. But, can it be explained from their structures or something like that ?
Mr. Chemist's user avatar
7 votes
1 answer
169 views

The 'bite size' effect in chelating ligands

My question is in relation to the following data, which describes the log K for the equilibrium of Mn+ + Ligand $\ce{<=>}$ [ML]n+ As far as my understanding goes, this is an example of the ...
Bartholomew696969's user avatar
1 vote
0 answers
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Which way is this coordination equilibrium likely to lie (entropic vs enthalpic factors)?

The question is asking where this aqueous equilibrium is likely to lie. My thought process is that, because Li+ is a smaller cation than Na+, with a greater charge density, upon displacement it will ...
Bartholomew696969's user avatar
4 votes
1 answer
528 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
2 answers
180 views

Crystal structures exhibiting dimeric arrangement of tetrahedrally coordinated cations

I am looking for inorganic crystal structures that exhibit tetrahedrally coordinated cations arranged in a vertex-sharing dimer arrangement, where the cation - shared vertex - cation angle is close to ...
AChemicalEntity's user avatar
1 vote
0 answers
22 views

What is the chemical mechanism at work during the carboxylation of graphene oxides?

The literature describes carboxylation as an efficient technique to increase the ability of graphene oxide to adsorb metals, as it increases the content of carboxylic acids in the material, while ...
Nathan Vinicius's user avatar
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0 answers
492 views

How heating of copper sulphate pentahydrate (blue vitriol) can be explained?

The chemical formula of copper sulphate pentahydrate, $\ce{CuSO4\cdot 5H2O}$ does not give information about its true structure because it's only an empirical formula. It forms a network solid. Two ...
Apurvium's user avatar
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2 votes
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108 views

What decides the number of water of crystallization molecules in a compound? [closed]

CuSO4.5H2O, FeSO4.7H2O, ZnSO4.7H2O are some well known compounds. Known as blue, green and white vitriol respectively. As we can see the first compound has 5 molecules of water while the latter two ...
Istiaq Shahriar's user avatar
-3 votes
1 answer
220 views

Aqueous solution of FeCl3 is yellow whereas other metals having the same d5 configuration are pale violet coloured. Explain the origin of the colour [closed]

The aqueous solution of the other metals with the same d5 configuration give pale violet colour. Pale colour could be caused by the d-d transitions. i got to know that Ferric chloride forms a self ...
SWATI's user avatar
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0 answers
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Can halide be a sigma donor?

When I took inorganic classes, I was told that halide is a pi donor. Assume I am using metal hexahalide why I can't put the $p_z$ orbital of the halides directing to the metal centre? With that halide ...
some one's user avatar
3 votes
1 answer
143 views

Assigning structure based on EPR spectroscopy

When given two copper(II) complexes - bis(N-3-chlorophenyl-salicydenaminato)copper(II) and bis(N-3-methylphenyl-salicydenaminato)copper(II) - how can you predict their EPR spectrum and hence their g ...
qwerty09's user avatar
-1 votes
1 answer
222 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
3 votes
0 answers
152 views

Why does Co(CO)4 exist as dimeric Co2(CO)8?

I was wondering why is this equilibrium below established at all... Why can't Co(CO)4 exist on its own, as a monomer?
Rudransh Sinha's user avatar
3 votes
0 answers
45 views

Electron count of complexes

For counting the electrons of the complex (RO)3W≡CMe, the book considers three RO- groups that donate a total of 10 electrons and it regards ≡CMe as [carbyne]- group in the ionic model and has a total ...
Cindy's user avatar
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Why doesn't Mn2+ ion form ammine complexes in aqeous medium?

Cations of 3d- elements particularly, the last four ones such as Cu2+ Zn2+ Co2+/Co3+and Ni2+ form metal-ammine complexes readily in aqeous solution, while the cations Mn2+ Cr3+ and Fe3+ usually dont. ...
Sudhagar's user avatar
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2 votes
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Why does the coordination of alkaline earths by graphene oxides increase as a function of the increasing ionic radius of the species?

The literature describes that the affinity of graphene oxides towards alkaline earth metals presents a positive correlation with their ionic radius (for example, Klímová et al. (2016) and Sófer et al. ...
Nathan Vinicius's user avatar
3 votes
0 answers
77 views

Why is hexacyanoferrate(II) coloured whereas tetrachlorocadmiate(II) is not, even though both lack unpaired electrons?

$\ce{K4[Fe(CN)6]}$ is coloured whereas $\ce{Na2[CdCl4]}$ is not. Even Laporte selection rule would suggest the tetrahedral cadmium complex to have a higher intensity of colour than the octahedral iron ...
Confused's user avatar
4 votes
1 answer
114 views

Can heterocyclic molecules form sandwich-like complexes?

As unsaturated heterocycles have the same planar structure as cyclopentadiene ion/benzene "sandwich" compounds, I was wondering if a similar coordination between metals can be achieved. When ...
Evamentality's user avatar
2 votes
1 answer
130 views

Common-ion effect vs complexation

Quoting from Wikipedia, The common-ion effect refers to the decrease in solubility of an ionic precipitate by the addition to the solution of a soluble compound with an ion in common with the ...
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