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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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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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
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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
35 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
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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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1answer
35 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
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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
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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
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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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Magnetic behavior of sodium thio-nitroprusside

Is $\ce{Na4[Fe(CN)5NOS]}$ contains $\ce{Fe(II)}$ and $\ce{NO+}$ and hence diamagnetic, or $\ce{Fe(III)}$ and $\ce{NO}$ and hence paramagnetic?If in this molecule NO transfers one electron to $\ce{Fe(...
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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
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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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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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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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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
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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
44 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
148 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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51 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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0answers
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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
79 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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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
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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
114 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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0answers
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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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0answers
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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
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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
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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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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
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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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0answers
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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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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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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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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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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
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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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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'...
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0answers
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Do species with more unpaired electrons attract magnets more strongly than those with fewer unpaired electrons?

My lecture notes state that you can distinguish between high spin and low spin complexes by their magnetic properties. This thought came to me: consider two octahedral crystal fields with a d7 ...
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Reference Request- good exercise book/reference material for ligand Field Theory? [duplicate]

Title. I currently own Problems in Molecular Orbital Theory and found it pretty helpful for my understanding, and was wondering if a similar book existed for ligand Field Theory (there is one chapter ...
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1answer
135 views

C4v point group complexes and the group orbitals (MO Theory)

Out of curiosity, what would the group orbitals be like in a C4v complex (square planar complexes or octahedral complexes with 5 identical ligands and 1 other) look like? I get a irreducible ...
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1answer
120 views

Is there a difference between a chelate ligand and a polydentate ligand?

I'm confused because my lecture notes state that chelate ligands are a subset of polydentate ligands.
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Are all ambidentate ligands monodentate?

Several websites define an ambidentate ligand as being monodentate. What about a ligand with say 3 atoms that can act as donor atoms, but due to the sterics of the ligand, only any two atoms can ...
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Is ammonium ion a positive ligand? If yes, please explain how does it coordinate with metal

In some books the examples for positive ligands are given as: $\ce{NO+}$, $\ce{NO2+}$, $\ce{NH2-NH3+}$, $\ce{NH4+}$, $\ce{H3O+}$, $\ce{PH4+}$. I can understand about the first three examples, but ...
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1answer
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Aqueous copper and how it reacts with NH3

I have learnt that you can test whether an unknown metal is copper by doing a simple test tube reaction. The reaction involves adding aqueous $\ce{NH3}$ to the test tube which contains the copper. ...
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2answers
180 views

Is Fe(OH)2 soluble in alkalis?

I have just started inorganic chemistry in school and I have just learnt about metal aqua ions and how they react in water. I learnt that $\ce{[Fe(H2O)6]^2+}$ reacts in water by losing a $\ce{H+}$ ...
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ionisation isomers [closed]

With ionisation isomers, how do you know which ligand (out of $\ce{Br}$ and $\ce{NH3}$ for example) exchanges with the compound outside the bracket?
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Distinguishing cis and trans positions

What I fail to understand is why does trans isomer contain $2$ $\ce{Cl}$ at axial positions but $2$ $\ce{NH3}$ are not taken to be so. Isn't the two $\ce{NH3}$ in the trans isomer in the picture cis ...