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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 [tag:carbonyl-complexes] instead. ...

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Explain why octahedral complexes of Ni+2 must be outer orbital complexes? [on hold]

Why is it that the two unpaired electrons pair up in the 3d shell? Then one 3d orbital, 1 4s and the rest 4d orbitals can be used for hybridization?
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Why does an octahedral entity split to 3/5Delta and -2/5Delta?

Can anyone please tell me how 2/5 and 3/5 showed up there? All the sites and books i've read directly state this, kinda like this is really obvious. I think it has something to do with the number of ...
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Does [Mn(CN)4]2- exist?If it exists what is its shape according to CFT? [on hold]

Does [Mn(CN)4]2- exist?If it exists what is its shape according to CFT? What i observe is that it is coming as d2sp hybridisation but we are not allowed to used hybridisation in cft so its not ...
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19 views

Why does crystal field energy split this way [on hold]

This is for an octahedral entity! My question is why does this split into 2/5 and 3/5 of the crystal field energy? Is this because there are 2 orbitals here and 3 orbitals there? Please help, I've ...
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21 views

Rhombohedral second-order Jahn–Teller effect in Au(II) complex?

I was recently listening to a talk about the following work[1] when the author mentioned that they explained the following. In this $\ce{Au(II)}$-porphyrin complex you observe two sets of $\ce{Au-N}$ ...
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25 views

Feasibility of Reactions [closed]

How do we in general check the feasibility of these given reactions?
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17 views

Why are 5-ringed saturated chelates more stable than unsaturated ones while 6-ringed unsaturated chelates are more stable than saturated ones?

5-ringed saturated chelates seem to be more stable than unsaturated ones. On the other hand, 6-ringed unsaturated chelates are more stable than saturated ones. Why do these hold true?
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28 views

Why is the probability of a didentate ligand to form a chelate with a central atom, high?

When one ligating group of didentate ligands (like ethylenediamine) is coordinated with a central atom, then the probability of the other ligating group being coordinated, and hence forming a chelate, ...
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22 views

π-backbonding in tungsten complexes

I need to find in which of the following complexes the M-CO bond is stonger: [WO3(CO)3] and [W(CH3)3(CO)3]. According to my knowledge this is chiefly determined by the π-backbonding and how good ...
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38 views

Help understanding the pi-properties of the NCS- ligand

Course knowledge When considering the NCS- ion, I take all atoms to be sp hybridized. This means that there are 8 electrons that are accommodated in the $\pi$-system. There are two orthogonal 3-...
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1answer
42 views

Is (Zn(OH)4)2- acidic or alkaline?

My chemistry teacher told me that $\ce{Al(OH)4^-}$, $\ce{Pb(OH)4^2-}$, $\ce{Zn(OH)4^2-}$ are called complex ions. So will they break down in some conditions and give out $\ce{OH-}$ to show alkaline ...
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1answer
81 views

Are crown ethers “recycled”, typically?

I know that crown ethers have the interesting property of strongly complexing alkali metals, which allows them to be used in organic solvents (eg. as "dissolving-activity enhancing agents" for ...
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15 views

Coordination number, or contact ion pair, or frequency number of potassium acetate

I need to have the experimental value of coordination number (= contact ion pair = frequency number) of aqueous potassium acetate. I have the number for KCL from the following article, but my efforts ...
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1answer
36 views

In Diazonium Ion why does N contain 4 bonds?

Nitrogen's valenc number is 3. Sometimes it can form a co-ordinate bond by donating it's lone pair electrons. In diazonium ion N has 4 bonds, then one of those 4 bonds must be a co-ordinate bond. ...
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19 views

Identification for qualitative analysis

The flow chart is indicative of a compound with a silver cation, because $\ce{Ag+}$ reacts with $\ce{I-}$ to form yellow $\ce{AgI}$. Since $\ce{Ag+}$ does not form a hydroxide complex, it forms the ...
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28 views

Nitrosyl complexes: oxidation state ambiguity

What is the oxidation state of chromium in $\ce{[Cr(NH3)(CN)4(NO)]^{2-}}$ ? Well if we assume $\ce{NO}$ to be bent that is $\ce{NO-}$, then oxidation state of chromium will be $\mathrm{+3}$. If we ...
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1answer
45 views

Why is there only one ionization isomer of [Cr(NH3)5(NO2)]Cl2?

How many isomers are possible for $\ce{[Cr(NH3)5(NO2)]Cl2}$? Consider all possible types of isomerism and draw each isomer. My texbooks presents only three possible isomers: $\ce{[Cr(NH3)5(NO2)]Cl2}$ ...
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0answers
56 views

Molecular orbital diagram for terminal metal-oxo complex with dative bonds

I am interested in terminal metal-oxo complexes and their electronic structure, specifically those with coordination numbers of 6, including the oxo ligand. I know that Fe(IV)-oxo complexes tend to ...
2
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1answer
53 views

Why is CO ligand higher than CN- in the spectrochemical series?

I've drawn MO diagrams for both molecules and they are isoelectronic. The main difference is that $\ce{C}$ is closer in electronegativity to $\ce{N}$ than it is to $\ce{O}$ so there will be less ...
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1answer
33 views

why do the complex [Cu(NH3)5NO2]SO4 show ionisation isomerism?

In ionisation isomerism, secondary valencies can be replaced by primary valencies on the condition that net charge going outside the coordination sphere must be equal to net charge coming inside it . ...
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1answer
166 views

IUPAC name of C₆(CH₃)₆²⁺

What is the correct IUPAC name (or least incorrect one, if the current rules can't precisely describe that) of the interesting species $\ce{[C6(CH3)6]^{2+}}$ (which is extensively discussed here), ...
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1answer
54 views

IUPAC nomenclature of chelates

I could finally get a copy of the Red Book 2005 from a library. In the chapter dedicated to nomenclature of coordinate complexes, while explaining the κ-system of specifying donor atoms, the following ...
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102 views

Cobalt Chloride in various solvent/water mixtures - tested

In a recent post the solvatochromic behaviour of cobalt chloride in acetone was discussed. There were some ideas how the acetone might influence the ratio between the blue $\ce{[CoCl4]^2-}$ and the ...
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1answer
88 views

Considering the d-d transition how, does tetracyanidonickelate(II) ion exist as a colored complex?

As I refer on google, the resources indicated that, the d block elements which have unpaired electrons as in their ions, when they are making complexes with ligands, they can absorb different ...
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27 views

What reactions will occur at the anodes and electodes of two iron electrolytic cells?

What reactions will occur at the anodes and electrodes of two iron electrolytic cells: both with iron metal electrodes, one with an iron(II) sulphate electrolyte, the other with an iron(III) sulphate ...
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30 views

Will potassium oxalate form stable complexes with Al 3+ AND Fe 3+ in an acidic solution?

I am trying to perform a complexometric titration of both Al 3+ and Fe 3+ in a sulfuric acid solution. I would be measuring the titration using a thermistor. The goal in this would be to complex all ...
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1answer
116 views

Why is the oxidation state of Co -1 in [Co(CO)4]-?

In $\ce{[Co2(CO)8]}$, most people say the charge of $\ce{Co}$ is 0. How does it become $\ce{[Co(CO)4]-}$? Most answers would say that $\ce{Co}$'s charge becomes -1. How does this work? -1 is not ...
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1answer
63 views

What is an uninegative ligand

I can't find a simple definition via google. All I get are research papers, that I don't understand.
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79 views

Failure to Locate Stationary Point in GAMESS

I'm currently trying to optimize the geometry of a complex using GAMESS at the B3LYP level. However, I keep failing to converge the SCF. I've already tried the following: increasing the number of ...
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1answer
33 views

Ammonia complex [closed]

I am desperately trying to find an aqueous chemical that will selectively form a complex with ammonia gas. Any suggestions please? I am building a gas sensor for ammonia
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39 views

Is there anyway to derive the number of water molecules in a hydrated salt, given just the formula for the anhydrous salt?

Is there anyway to derive the number of water molecules in a hydrated salt, given just the formula for the anhydrous salt? That's pretty much it. If not, why? For coordinated water, my guess is ...
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1answer
105 views

Why or why not can hydroquinone and 2H-pyrrole act as ligands?

I want to understand why hydroquinone and 3H-pyrrole can or cannot act as ligands in transition metal complexes. If they are ligands, then what is their denticity? I'm trying to understand the ...
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1answer
115 views

Is there a theoretical way to predict the coordination number a metal can have in a complex? [closed]

We know that metals can form complexes with different coordination numbers, but I was told that certain metals have a greater probability to have a certain coordination number. But I was not able to ...
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62 views

What is the hybridization of iron pentacarbonyl?

What is the hybridization of $\ce{[Fe(CO)5]}$? Is this correct?
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136 views

Does the wavelength of light absorbed by a complex depend upon extent of splitting or stability?

Background: we were doing Crystal Field Theory in school when this question popped up. Specifically we were talking about stability obtained due to the chelate effect and if the extra stability in a ...
4
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1answer
54 views

Does the mixture of a ligand exchange reaction contain all the complexes obtained in the part reactions?

A ligand exchange reaction involves many part reactions. So, does the mixture contain all the complexes from those part reactions? Quoting an example from ChemGuide: This can be written as an ...
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Differences between hexaaqua cobalt (III) complex and hexammine cobalt (III) complex in aqueous solution

Why is $\ce{[Co(H2O)6]^3+}$ a strong oxidizing agent and $\ce{[Co(NH3)6]^3+}$ stable in Aqueous solution? I think this has got to do with Pairing Energy and Ligand strengths of $\ce{H_2O}$ and $\ce{...
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Do metal ions of 4d and 5d series always form low spin complex?

I've recently come across a source where it stated that all 4d and 5d metals form low spin complexes irrespective of the strength of ligand. I'm not sure of the authenticity of the source and couldn'...
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1answer
57 views

Is the dimethylglyoximate anion ambidentate or not?

In class, my professor said that dimethylglyoximate is a special ambidemtate ligand that can donate lone pairs via both nitrogen (which it normally does), and oxygen (very rarely). On googling ...
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1answer
194 views

How to calculate the 15 geometrical isomers of an octahedral complex with all ligands different?

Suppose we have a complex of type $\ce{[Mabcdef]}$ then we know it’ll show geometrical isomerism. According to my textbook (Cengage Inorganic Chemistry II, Page 7.37) there are 15 geometrical isomers ...
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Is primary valency always ionizable?

In my textbook it is written that primary valences are ionizable. I saw a case of complex $\ce{[Co(NH3)5Cl]Cl2}$ Here it is written that primary valency is 3. The $\ce{Cl}$ inside coordination sphere ...
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1answer
280 views

Is chromium (III) green or violet in solution? [duplicate]

Is chromium (III) green or violet in solution? In terms of oxidation reactions between chromate and $\ce{Cr}$ (III) it forms a green color in solution, but when I searched online in different sources ...
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1answer
55 views

Is there an upper limit on the coordination number of a coordination compound? [duplicate]

From the Gold Book, coordination number is: In an inorganic coordination entity, the number of σ-bonds between ligands and the central atom. π-bonds are not considered in determining the ...
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1answer
83 views

Reversibility of the binding of carbon monoxide to haemoglobin

I recently learnt the basic mechanism of haemoglobin: oxygen forms coordinate bonds with the $\ce{Fe^2+}$ ion in haem groups, and this reaction is reversible to allow oxygen to be released. I also ...
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1answer
208 views

The structure of sodium cuprous thiosulphate

While studying about copper sulphate, I came across a reaction involving sodium thiosulphate (Hypo) and copper sulphate. Although I don't know the utility of this reaction, I felt that it was ...
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1answer
75 views

Stretching frequency of nitro and nitrito

I got the values of the stretching frequency of nitro and nitrito ligands from this webpage. I understand why stretching frequencies are close in nitro and well separated in nitrito. How to explain ...
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1answer
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Hybridisation of Co in [Co(ox)3]3-

Will the hybridisation of of $\ce{Co}$ in $\ce{[Co(ox)_3]^3-}$ be $\ce{ sp^3d^2}$ or $\ce{ d^2sp^3}$? The question in which I found it has mentioned the answer to be $\ce{d^2sp^3}$ while I was ...
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1answer
83 views

Jahn Teller Effect for d4 low spin configurations

Why does Z-in take place in $d^{4}$ low spin configuration whereas in Z-out one can get all the 4 electrons in $d_{xz}, d_{yz}$ which would lead to lower energy
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1answer
62 views

Chirality in coordination octahedral compounds [duplicate]

Isn't this molecule achiral? I mean if I flip the mirror image on right by 180 degrees(like we do to determine chirality in tetrahedral carbons) it would be superimposeable? But apparently it is ...