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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Organic Photoelectric Effect [closed]

When researching the work function of photoelectric materials, only the pure element is shown. I was wondering if coordinate compounds of a certain element would display the same work function as the ...
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Calculate EAN for [Fe(diars)2Cl2]Cl? [closed]

I know EFFECTIVE ATOMIC NUMBER (EAN) as the following • The sum of the number of electrons, donated by all ligands and those present on the central metal ion or atom in the complex is called an ...
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How tetraamminecopper(II) is formed? [duplicate]

I'm trying to get a sense of how $\ce{Cu^2+}$ and $\ce{NH3}$ are bonded together because it doesn't make any! I understand that $\ce{NH3}$ has a lone pair of electrons that can be donated (right?), ...
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Which acetate salt is blue and turns yellow when dissolved in water?

***Update Some questions I am considering to try to answer this question; When dissolving the powder in acetic acid, which ions are present? From what I've read, I haven't found any acetate salts ...
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22 views

Crystal field theory: splitting energy and stability

In crystal field theory, we admit that in a coordination compound there are only electrostatic interactions between the d orbitals of the central metal cation and the ligands (which are considered as ...
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2answers
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The colors that we see [closed]

I have a question. When I was studying Coordination Compounds, I came across this para: When a sample absorbs light, what we see is the sum of remaining colors that strikes our eyes. Observed and ...
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1answer
57 views

Bridging Hydride Covalent Model Electron Count - Hartwig

How can a bridging hydride be considered a 3 electron donor in the covalent model for electron counting? On page 3 of John Hartwig's "Organotransition metal chemistry" textbook [1], he lists ...
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44 views

Describe the formation of the [PbCl4]2- complex ion

The $\ce{[PbCl4]^{2-}}$ complex ion is formed when $\ce{PbCl2}$ is exposed to excess $Cl^-$ ions in solution as explained here and here through the following reversible reaction: $$\ce{PbCl2(s) + 2Cl^-...
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Explanation of the orbital energies resulting from Jahn-Teller distortion of octahedral complex using MO theory

I am confused about the energies of the orbitals after Jahn-Teller distortion of an octahedral complex. Take elongation for example. To my understanding, since the ligands on the $z$ axis move away, ...
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112 views

Reaction/complexation of aluminium chloride and acetic acid

Thinking about Friedel-Crafts acylation using carboxylic acid anhydride got me wondering about how exactly aluminium chloride ends up in that reaction. Generally, despite the fact that Friedel-Crafts ...
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1answer
41 views

Tendency of formation of complexes in Group-1 elements

My book states the following: Down the group(Group-1), tendency to form complexes decreases due to decrease in charge density$\bigg(\frac{\text{charge}}{\text{radius}}\bigg).$ This results in ...
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1answer
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Which ligand names have to be parenthesized while naming the Mononuclear Coordination entities

While studying about the Nomenclature of Coordination Compounds I came to know that While writing formulae of Mononuclear Coordination entities polyatomic ligands are enclosed in parenthesis and also ...
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1answer
53 views

Does spectrochemical series trend depend on the metal center?

Can the trend of spectrochemical series vary/fluctuate according to the central metal atom (CMA) that is being used? For example, for the CMA $\ce{Ni^2+}$ the ligand $\ce{H2O}$ will have more CFSE ...
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113 views

Colours in Coordination Compounds

I have read that NH3 acts as an SFL with a M+3 metal ion and acts as a WFL with a M+2 metal ion. It also states that when NH3 forms a complex with the M+2 ion, its stability constant is 10^11. When ...
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1answer
120 views

What is the correct formula for diamminechloridonitrito-n-platinum(II)?

Is the correct formula for diamminechloridonitrito-n-platinum(II) $\ce{[Pt(NH3)2Cl(NO2)]}$ or $\ce{[PtCl(NH3)2(NO2)]}$? I was taught that the sequence of symbols within the coordination entity should ...
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How is the UV-visible spectra of carbonatotetraamminecobalt(III) nitrate interpreted?

In a laboratory practice I have done a characterization of the $\ce{[Co(NH3)4CO3]NO3}$ and obtained the following spectra: I don't know if the band between 300 nm and 400 nm can be due to the effect ...
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1answer
90 views

Can copper sulfate react with terpenes (such as limonene and terpinenes) at room temperature?

I am just wondering, can I make a metalorganic or organometallic complex of copper and limonene/terpinene/phellandrene in the form of lime oil? If so, what is the formula of the complex formed? I ...
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51 views

In metal complex electron counting, is the neutral or ionic formalism more correct?

I have been practicing finding total valence electron counts by both methods, and a few points have arisen that have confused me. 1) Which method gives the true d-electron count? From what I ...
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Why doesn't octahedral d8 system exhibit Jahn-Teller effect?

Chemistry LibreTexts stated clearly that (under the section 'Large $\Delta$' and 'Small $\Delta$') octahedral d$^8$ system does not exhibit Jahn-Teller distortions. But then it stated also: ...Some ...
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Is Porphyrin Planar?

I have been looking at this diagram from quite some time, I know the 18 pi electron cycle that forms porphin(e) is definitely planar but what about the whole molecule?... The Nitrogen's act as a ...
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1answer
310 views

Which are the Geometrical isomers of the complex [Cr(NH3)2Cl2(en)]+?Is it one or two?

I was recently studying coordination compounds and i came across optical isomerism shown by complexes.I think that the complex i gave above have 4 geometrical isomers(I think this is where I am wrong, ...
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Synthesis of Pt(II) complex using trans effect

By making use of the trans-effect in platinum(II) complexes, show efficient routes for the synthesis of all the possible isomers of $\ce{[PtCl(NH3)2(py)]+}$ (where $\ce{py}$ = pyridine) from the ...
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1answer
80 views

Does N in NH3 ligand gains formal positive charge as N in ammonium ion?

Ammonium ion is formed when N in $\ce{NH3}$ forms a coordinate covalent bond with a proton $\ce{(H+)}$ (or amine as shown in below picture) as a result the N gains a formal positive charge and a ...
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1answer
296 views

How to find the oxidation number of Co and Cr in [Co(NH3)6] [Cr(C2O4)3]?

In the question I actually got I had to name the above compound, and I know how to name it but I don't know how to find the oxidation number of the above compound(which has to be mentioned in the ...
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1answer
34 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 ...
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1answer
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How can I mask the Chromium (III) and Chromium (VI) ions in my solution?

I want to conduct a quantitative analysis on my acid etching solution for my Aluminum pre-treatment process. The easiest way for me to conduct my quantitative analysis of Al is through complexometric ...
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Crystal Field Splitting Energy and Metal Energy Level

Second and third row metals are stated to often have higher crystal field splitting energies than first row metals. The argument is usually made that the more diffuse 4d and 5d orbitals are capable of ...
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When is ammonia and water a strong ligand?

While studying the spectrochemical series, my sir said that as ammonia and water lie in the center, their behaviour as a ligand is tough to judge. For example if we have CO as a ligand, we know that ...
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1answer
46 views

Geometry of the transition metal complex in solid dipotassium bis(oxalato) copper(II) tetrahydrate

I was thinking of the geometry of the transition metal complex in solid $\ce{K2[Cu(ox)2] · 4 H2O}$ solid around the $\ce{Cu(II)}$ ion. At first I thought square planar, but is it possible or is there ...
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Can someone help with the nomenclature of this metal complex. MarvinSketch is giving me trouble

I’m trying to get a name for the structure above using MarvinSketch for my undergraduate senior thesis. This is the first time I’ve had to draw a metal complex in MarvinSketch, and I’m having trouble ...
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1answer
87 views

Is there an 'easy' way to determine if a ligand is a pi acceptor, donor or neutral?

First of all I am confused how something can be pi neutral? something either does or doesn't have filled p orbitals for example. given something I have never seen acting as a ligand before like ...
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29 views

Beer Lambert law when complex is tetragonal (Jahn-Teller elongated)

I wondered what modifications there would be to the Beer Lambert law to find the molar extinction coefficients for the solution if the solvent contained the ligands which bind to the metal centre of a ...
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70 views

Coordination compound nomenclature for [Cu(acac)(bpy)]BPh4

The title says it all really. I thought it would be acetylacetonatobipyridinecopper(II) tetraphenylborate. Is this correct? I feel as though it looks a bit clumsy and wasn’t sure if I was supposed to ...
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115 views

Comparison between Molecular Orbital Theory and Valence Bond Theory

I have been reading about introductory Molecular Orbital Theory lately. Till now, I have used Valence Bond Theory to evaluate bonding. I have a few questions about it:- In VBT, we used the idea that ...
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330 views

Why does [Ni(gly)2] show optical isomerism despite having no chiral carbon?

For optical isomerism chiral carbon should be present i.e. carbon with four different groups but this compound doesn't have one then why does it show optical isomerism?
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1answer
101 views

Ambiguity in definition of primary valency in Werner's theory

In Concise Inorganic Chemistry (5th Edition) on page 196 , the primary valency of $\ce{[Co(NH3)5Cl]Cl2}$ is given to be 2. In other textbooks and in the question here, we get the idea that: The ...
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1answer
28 views

Wavelength and Colour in Coordination complexes

My textbook said that coordination complexes with weak field ligands require a larger wavelength for obtaining enough energy for electron transfer(and hence, the manifestation of a colour), but if E = ...
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1answer
226 views

Naming and structure of PtCl4.2HCl (complex/coordination compound)

Given that $\ce{PtCl4.2HCl}$ when reacted with excess of $\ce{AgNO3}$ produced zero moles of $\ce{AgCl}$, I understand that all the chlorine atoms are inside the coordination sphere. But what will the ...
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2answers
83 views

Is plane of symmetry a necessary and sufficient condition for optical inactivity in coordination compounds? [closed]

In organic chemistry, we have to check for all three types of symmetry in a compound to check its chirality, ie, plane, alternate axis and centre of symmetry. But in coordination compounds, do we need ...
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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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Ionic radius for tetrahedral metal–ligand complexes

The ionic radii for metal–ligand complexes that are in an octahedral coordination are easy to find. I understand that when the $\mathrm{e_g}$ orbital is filled, the ionic radius increases because the ...
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Nickel(II) acetylacetonate crystals coming out blue

An experiment in my class has us synthesising the acetylacetonate complex from hydrated nickel chloride being added to a solution of ammonia, acetylacetone and water. The products came out pale blue, ...
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1answer
106 views

Denticity of bridging ligands

How would we assign denticity to bridging ligands? For eg, consider $\ce{NH^-_2}$, it has 2 lone pairs and can hence act as a bridging ligand, making 2 metal-ligand bonds. So I thought it should be ...
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1answer
125 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 ...
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1answer
60 views

Jahn Teller Effect on Metal Complexes

I've been learning how the Jahn Teller Distortion effects the orbitals in Metal complexes and how the splitting of eg and t2g orbitals happens. But the book mentions that the effect is strong for ...
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0answers
52 views

Molar conductivity in compounds showing coordination isomerism

Question Which of the following complex has lowest molar conductivity? $\ce{[Co(NH3)6][Cr(NO2)6]}$ $\ce{[Cr(NH3)5(NO2)][Co(NH3)(NO2)5]}$ $\ce{[Cr(NH3)4(NO2)2][Co(NH3)2(NO2)4]}$ $\ce{[Co(NH3)5(NO2)][...
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2answers
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Possible structure if a compound like AB4 is polar?

I was asked the following question in JEE Mains (2nd September, Shift 1) 2020, If a compound AB4 is polar (having non-zero dipole moment), then it's structure could be (A) Square planar (B) ...
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Metal coordination in enzymes: What type and number of bonds form between amino acid residues and Fe(II)?

My understanding: Transition (d-block) metals, as found in intracellular proteins, are limited to about 10 elements including amongst others Fe, Ni, and Cu. Due to the reductive environments inside ...
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73 views

Coordination number in π-complexes

I wanted to know what is the coordination number of the metal atom in π-complexes like Zeise's salt, ferrocene and dibenzene chromium. I found some data on it but its a bit contradicting. Can anyone ...
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918 views

Nomenclature of K2(PdCl4) [closed]

In the compound $\ce{K2[PdCl4]}$, the oxidation state of Pd is +2 so as per the nomenclature rules, the name of the central metal inside the coordination is simple if it's a cation. So if we name the ...

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