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 [tag:carbonyl-complexes] 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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What is the hybridization of copper in [Cu(NH3)4]^{+2}? [duplicate]

In the valence bond theory section of my textbook, for the $\ce{[Cu(NH_3)_4]^{2+}}$ complex it is written: "... physical measurements have indicated that the complex has square planar geometry. One ...
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50 views

Ce₂(SO₄)₃ solubility in water [duplicate]

I have mostly come across examples of solids whose solubility increases in liquids with an increase in temperature. However, there seem to be exceptions to generalized rule this such as the solubility ...
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Effect of Synergic Bonding on Bond Lengths in Metal Carbonyls

Consider the metal carbonyl, pentacarbonyl iron(0). There exists synergic bonding between the central metal atom, iron and the neutral carbonyl ligands. This strengthens the metal-ligand bond but ...
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Structure and oxidation state of bridging complexes

I am confused about the structure of bridging complexes with the bridging ligands as $\ce{OH-}$ or $\ce{NH2-}.$ Aren't they both monodentate ligands? And if they form a simple coordinate bond, then ...
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66 views

Does a complex that has no overall charge still have color?

The iron complex $\ce{[Fe(H2O)6]^2+}$ is colored but I'm wondering, if a pair of chloride ion is inserted on its secondary valency to form [FeCl2(H2O)6], does the complex loose its color or not?
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63 views

Why does only the cis-isomer of potassium dioxalatodiaquochromate(III) form?

A friend of mine performed a standard synthesis reaction of potassium dioxalatodiaquochromate(III) by adding potassium dichromate to ethandioic acid dihydrate and a little water. The synthesis ...
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21 views

Why is it important to know the spin of bioinorganic complexes?

During a bioinorganic chemistry course, my teacher gives a lot of importance to spin states of metal ions and how they changes (or not) after the formation of a complex. For example, when hemoglobin'...
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34 views

How is Mn+7 in the Permanganate ion considered as momentarily reduced to +6 in LMCT? [duplicate]

I saw this passage on a book and it says that Ligand to Metal Charge Transfer (LMCT) overpowers d-d transitions thus the permanganate ion has an intense purple color. However, it was mentioned that ...
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41 views

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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31 views

Determining geometry of coordination compund without experimental data [closed]

How can I determine if a coordination compound has a tetrahedral or square planar geometry without any experimental data (such as magnetic spin) by just looking at its formula? For example, what is ...
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1answer
33 views

Electronic configuration in [Ni(CN)4]2-

$\ce{[Ni(CN)4]^2-}$ is a low spin , inner orbital complex having $\mathrm{dsp^2}$ hybridisation. According to Crystal Field Theory, $\ce{CN^-}$ is a strong field ligand that causes pairing of ...
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1answer
79 views

Why is Polonium the only metal to crystallize forming Simple Cubic Cell?

I have read that Polonium is the only metal that crystallizes forming SCC. I searched for a concrete explanation but all they were saying is the stability of Polonium at STP. I can't really comprehend ...
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1answer
51 views

When H2NCH2CH2PH2 acts a monodentate ligand, it is the phosphine end that chelates. Why is that?

In some occasions, if the ligand acts on Pd it do so as a monodentate ligand. I am attempting to explain this phenomenon but came into a block.
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Does dichlorobis(triphenylphosphine)nickel(II) have a d⁰ electron count?

I am currently in dilemma because I'm trying to construct an octahedral splitting diagram for the $\ce{NiCl2(PPh3)2}$ complex. If the complex is $\mathrm{d^0}$ system, how would I determine whether ...
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1answer
56 views

What kind of isomerism does Ni(PPh3)2Cl2 have and what is their IUPAC name? [duplicate]

I know that there are 2 isomers that $\ce{Ni(PPh3)2Cl2}$ have and they exist in equilibrium. I am tempted to name them cis- and trans- but it does not sound right.
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1answer
40 views

What makes a compound basic? [closed]

Aluminum chlorohydrate is often referred to as basic aluminum chloride. The pH value of ACH is about 4. How is basicity in this context defined?
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2answers
67 views

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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1answer
49 views

Products of the reaction between chromium(III) chloride, zinc and sulfuric acid

The aim of my experiment was to make a Cr(II) aquacomplex in situ, and for that I have the reaction: $$\ce{CrCl3·6H2O + Zn}$$ and I add concentrated sulfuric acid to it. I know that chromium(III) ...
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1answer
32 views

Horizontal symmetry plane of cis-dichloroosmiumtetracarbonyl

Consider the molecule $\ce{Os(CO)4Cl2}$ with a drawing given below via Chemtube3d: I thought in this molecule, if I drew a horizontal plane, then a $σ_\mathrm{h}$ would be present i.e. A ‘horizontal’ ...
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1answer
52 views

Reaction of coloured metal complexes with water and sulfuric acid [closed]

Reaction of coloured metal complexes with water and sulfuric acid I recently started researching the coloured compounds made from transition metals focusing on one with oxidation state II, so Mn,Fe,...
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1answer
82 views

Naming this iron complex: Fe2Cl6[H2O]5

This is the iron complex in question: $\ce{Fe2Cl6[H2O]5}$ I'm pretty sure according to the nomenclature it should be: pentaaquahexachloroiron(III) but I wanted to check somewhere to be sure.
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Why is there no effective alternative to metal salts in antiperspirants?

Metal salts, especially aluminum compounds are used in antiperspirants to prevent sweating. I found out aluminum chloride hexahydrate, which is found in most antiperspirants, undergoes an acid-base ...
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What happens if an orbital has no entry in a point group table?

A while ago I cited a few passages from a book on $f$-orbital contributions in metal complexes. And although usually the $4f$-orbitals are too isolated to really do chemistry and the elctron density ...
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2answers
777 views

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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How can I change the synthetic conditions for powder product into single crystal growth?

I am working on growing metal-organic frameworks crystals based on hexatopic linker for different metals. Upon using some synthetic conditions it gave fast precipitation into powder material after ...
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29 views

Electron-donating trends for ligands bound to metal complexes

Imagine an inorganic complex with a bunch of terminal ligands. All else the same, would $\ce{F-}$ or $\ce{Br-}$ ligands be more electron-donating and why? Of course, in terms of $\mathrm{p}K_{\mathrm{...
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1answer
890 views

Why are low spin tetrahedral complexes so rare?

As I was going through Concise Inorganic Chemistry by J. D. Lee, I realised that there are simply no low spin tetrahedral complexes mentioned in the book. Is there any specific condition required for ...
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1answer
60 views

What is the range of values of n in [Cu(NH3)4(H2O)n]SO4?

My textbook represents the copper ion as "tetraaminecopper(II) sulfate-1-water", so I assumed that this complex ion has only 1 water of crystallization. Then, in the Wikipedia article, they represent ...
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1answer
49 views

How to find oxidation state of Co and Cr in [Co(NH₃)₄(NO₂)₂][Cr(NH₃)₃(NO₂)₃]?

Which of the following options represents the oxidation state of $\ce{Co}$ and $\ce{Cr}$ in the given complex? $$\ce{[Co(NH3)4(NO2)2][Cr(NH3)3(NO2)3]}$$ (A) $2, 3$ (B) $3, 2$ (C) $3, 3$ ...
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1answer
204 views

Magnetic moment from given CFSE value

Spin magnetic moment of a octahedral complex having CFSE = $– 0.8∆$ and surrounded by weak field ligands can be: A. $\sqrt{15} \space \mu_B$ B. $\sqrt{8} \space \mu_B$ C. (A) & (B) ...
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55 views

Coordination number of complex resulting from sodium nitroprusside test

In my textbook the following reaction is given to identify sulfide ion: $$\ce{Na2[Fe(CN)5(NO)] + Na2S -> \underset{\text{violet solution}}{Na4[Fe(CN)5NOS]}}$$ Here's what I want to know: Is $\...
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61 views

Why do tetrahedral organic molecules show stereo-isomerism, but not tetrahedral transition metal complexes?

Both types of molecules show different arrangements of the molecule in space, so they should qualify for optical isomerism right?
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1answer
119 views

Why do some ions form tetrahedral complexes more readily than others? [closed]

Why does Co$^{2+}$ readily form tetrahedral complexes such as [CoCl$_4$]$^{2-}$, whereas Fe$^{2+}$ usually forms octahedral complexes?
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106 views

Disproportionation of Au(II)

Cu(II) and Ag(II) complexes are known to exist while Au(II) is unstable and disproportionates to Au(I) and Au(III). My guess as to possible reasons to this effect is that Au(II) like Cu(II) and Ag(II)...
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2answers
170 views

Statistical model of ligand substitution

Recently, I was told that in case of a particular step of a generic ligand substitution reaction: $$\ce{M(OH2)_{$N - n$}L_{n} + L <=> M(OH2)_{$N - n - 1$}L_{$n + 1$} + H2O}$$ The probability ...
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3answers
149 views

Is [Co(NH₃)₄Cl₂]Cl paramagnetic or diamagnetic?

$\ce{NH3}$ is known to be a strong field ligand, while $\ce{Cl}$ is known to be a weak field ligand. Is $\ce{[Co(NH3)4Cl2]Cl}$ a high spin complex or a low spin complex? I assumed this to be a high ...
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26 views

Changes in metal-ligand bond lengths of coordination compounds

Consider change in length of the metal-ligand bond in the following reaction: $\ce{[Cr(CN)6]^3- + e^- -> [Cr(CN)6]^4-}$ I initially had two theories (based on general electrostatics and d-...
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Why do polyoxometalates have good electrochemical/ redox properties?

Many authors are using polyoxomethalates immobilised in carbon nanomaterial as electrocatalysts for energy related reactions (ORR, HER, OER). Other metal alloys have also shown to be successful as ...
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Metal complexes and bonding of ligands

I am currently learning about transition metal complexes, however I keep seeing complexes like $\ce{[Al(H2O)6}]^{3+}$ but aluminium isn't a transition metal. Is this a case that any metal can form a ...
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2answers
107 views

Colour change when excess ammonia added to [Cu(H2O)6]2+

Since ammonia is a stronger ligand than $\ce{H2O}$ shouldn't the colour of the new solution $\ce{[Cu(NH3)4(H2O)2]}$ be lighter as the energy gap will be higher and so light with higher frequency and ...
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1answer
43 views

Treatment of ambidentate ligands in geometrical and optical isomerism

Are ambidentate ligands considered different entities when they donate through different atoms? For example will a hypothetical square planar complex like [Pt(ONO)2(NO2)2] show geometrical isomerism?
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236 views

Is cobalt (III) hexaaqua paramagnetic or diamagnetic?

The complex ion $\ce{[Co(H2O)6]^3+}$ has $\ce{Co}$ in the $+3$ oxidation state, meaning it has an electron configuration of $[Ar] 4s^0 3d^6$. Therefore it has 4 unpaired electrons and would be ...
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1answer
61 views

How to determine the number of water ligands attached to Pd in palladium chloride aquacomplex PdClₓ · yH₂O?

Normally this can be achieved using UV-vis: there is a strong absorbance around wavelength 220 nm which varies based on the number of ligands. If the palladium concentration is too high, the solution ...
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Can factors such as non-chelating ions in solution or the temperature of solution change the d orbital splitting of complexes?

My currently primitive understanding of metal complexes is that the d orbital splitting depends on: Identity of central ion Charge density of ligand Geometry of complex ion oxidation number of ...
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38 views

ML6 Type Coordinate Complexes - Drawing a Molecular Energy Orbital Diagram

In class we recently discussed how to draw out molecular orbital energy diagrams for compounds such as NH3 (ammonia). Building upon this, we touched on how to construct a molecular energy diagram for ...
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2answers
68 views

Equilibrium constant for complex cobalt ion

What is the equilibrium constant for the $\ce{Co(H2O)_6^{2+}(aq) + 4 Cl-(aq) <=> CoCl_4^{2-}(aq) + 6H2O(l)}$? I've looked at various sources but none seem to yield the actual equilibrium ...
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0answers
59 views

Shortcut method to find atomic term symbols ignoring the spin orbit coupling

Is there any shortcut method by which we can find the atomic term symbols ignoring the spin-orbit coupling, i.e. ignoring the values of J. For instance, when writing the d-d transitions for any ...
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36 views

How do we get the wave function of Ligand Group Orbitals with the same symmetry as that of the corresponding metal orbitals

In the book Principles of Structure and Reactivity by Huheey, Chapter 14, the author has taken linear combination of ligand orbitals to form ligand group orbitals and then further combination of LGOs(...
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1answer
50 views

N-heterocyclic carbene metal complexes. Question about the delocalization of the nitrogen lone pairs

I am wondering why nitrogen lone pairs are delocalized in NHC metal complexes. What I can think of is, when complex is formed, plus charge is formed on the carbon atom and therefore delocalization ...
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42 views

Aufbau's principle violation at the time of complex formation

My doubt is why don't we write 4s orbital before 3d as it is lower in energy according to Aufbau's principle? (I'm getting this info from other sites that 3d comes before 4s in transition metals but I'...