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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4
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1answer
81 views

What is the shape of [Cr(NO)₄]?

I was learning about crystal field theory recently. I am quite confused about predicting the shape of $\ce{[Cr(NO)4]}$ complex because I am not able to conclude whether it will be square planar or ...
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15 views

How do a write the skeletal structure of the a transition metal complex in particular a BaIrO3 Perovskite? [closed]

I want to write down a 2d representation of the BaIrO3 Perovskite like I would with polyacetylene. I now people can draw these diagrams for transition metal complexes, but i don't really understand ...
4
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1answer
229 views

What do 'sigma' and 'pi' in front of ligands in the formula of a coordination compound mean?

The following coordination compound was given in the book Concise Inorganic Chemistry by J.D. Lee (Adapted by Sudarsan Guha) under the topic 'Effective Atomic Number (EAN)': $\ce{[Ti(\sigma -C5H5)2 (\...
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0answers
37 views

Distinguishing between different geometries of bromochlorobis(triphenylphosphine)platinum(II) using ¹⁹⁵Pt NMR

Question The question off which I am basing my question assumes that $\ce{[PtClBr(PPh3)2]}$ can exist in either the square-planar or tetrahedral geometry. If one would use $\ce{^{195}Pt}$ NMR ...
4
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1answer
150 views

Why is acetate a monodentate ligand?

Why is the acetate ion considered a monodentate ligand as opposed to a bidentate ligand considering both oxygen atoms can donate their respective lone pair of electrons?
3
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1answer
64 views

Structural isomers of hexaammineiron(III) hexacyanidocobaltate(III)

Find the number of structural isomers of $\ce{[Fe(NH_3)_6][Co(CN)_6]}$ This was a question solved by my teacher as follows: The $\ce{CN}$ will show linkage isomerism while $\ce{NH_3}$ and $\ce{CN}$ ...
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0answers
44 views

What is the electron configuration of VO^2+ and VO3^1-? How do you determine the valence of vanadium in VO3^1- and VO^2+ [closed]

I am getting confused about how to go along with this so can someone please explain the process to figure this out as soon as possible :( Thank you! Also I was figured out that the oxidation number of ...
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0answers
19 views

(Al(OH) 6) 3 minus structure [closed]

Why in [Al(OH) 6] 3minus there are 6 OH I understood why there are 4 in Al(OH) 4 1 minus by writing electronic configuration I understand there is 1 ligand in Al(OH) 4 1 minus Are there 3 or 6 ...
5
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1answer
69 views

Naming of [Pt(py)4][PtCl4]

Why is $\ce{[Pt(py)4][PtCl4]}$ called tetrakis(pyridine)platinum(II) tetrachloridoplatinate(II) and not tetrapyridineplatinum(II) tetrachloridoplatinate(II)? I thought you use tetrakis for ligands ...
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2answers
244 views

Why can't ligands with “locked structures” undergo chelation?

The following quote is from the book Concise Inorganic Chemistry by J.D. Lee (Adapted by Sudarsan Guha), from the chapter "Coordination Compounds", page 177: ...it must be noted that $\ce{NH2NH2}$ ...
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1answer
52 views

What is the electron count in this nickel complex?

Our class has started learning about electron counting using the ionic method. I was having a little difficulty, especially when there are two metals in one complex, so I looked at Wikipedia for help. ...
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59 views

Why is the crystal field splitting energy larger for square planar than octahedral complexes?

I recently came across a fact that for the same combination of metal and ligand, the crystal field splitting energy for square planar complexes is larger than that of the corresponding octahedral ...
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20 views

Why are t2g orbitals not involved in sigma bonding and eg orbitals in pi bonding?

Its always seen that t2g is involved predominantly in pi bonding according and eg,a1u,t1u are involved in sigma bonding. How is this theorised ?
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108 views

Interference of Ca-EDTA with fluoride delivery in mouthwash

The goal of fluoride mouthwash is to deliver $\ce{F-}$ to the surface of the teeth to turn hydroxyapatite in the dental enamel into fluorapatite. Typically sodium fluoride or stannous fluoride are ...
1
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1answer
50 views

Can methanol act as a ligand? [closed]

As methanol is both a lewis acid and a lewis base, the lewis base part suggests that it can act as a ligand as many bases are. So, is methanol a ligand? And what is the reason behind it?
5
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1answer
341 views

Does Fe(CO)6 really exist?

I was given a question to draw the structure of $\ce{Fe(CO)6}$ and tell the hybridization. Hybridization came out to be $\ce{sp^3d^2}$ and structure as Octahedral. But does $\ce{Fe(CO)6}$ really exist?...
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1answer
48 views

What is the hybridisation of [Co(H₂O)₆]³⁺? [duplicate]

There's a lot of ambiguity in the hybridisation of $\ce{Co^3+}$ in its hexaaqua complex; is it a high spin or low spin complex? As theoretically the CFSE is less than P so it should be low spin, but ...
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0answers
45 views

Why is [Ni(en)3]2+ paramagnetic? [duplicate]

I could not find a satisfactory answer for the above question anywhere on the internet/on SE. Why does $\ce{en}$, which is a strong field ligand, not cause the electrons to pair up in $\ce{[Ni(en)3]^2+...
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1answer
25 views

Reactions of Depressants

In the froth flotation process, the concentration of a sulphide ore takes place using $\ce{NaCN/KCN}$ as a depressant. It forms a soluble complex with the impurity sulphide. Taking the particular ...
4
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1answer
128 views

Benzene as a pi-acceptor?

In coordination chemistry, we classify ligands as sigma donors, pi acceptors and donors. Benzene is a pi donor, as is the cyclopentadienyl anion, but do these two possess any pi acceptor character? (...
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2answers
90 views

Do all metal salts in aqueous solution contain metal aquo complexes?

I know that nickel nitrate in aqueous solution contains the metal aquo complex ion $\ce{[Ni(H2O)6]^2+}$. But do all metal salts in aqueous solution contain such complex ions? If not, on what factors ...
3
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2answers
96 views

Number of optically active isomers of [Co(NH3)2Cl2(NO)(OH)]?

My Attempt: Since Compound is of the form M[a2b2cd] I got three optically active isomers of the form M[(ab)(ab)(cd)] , M[(ab)(ac)(bd)] , M[(ab)(bc)(ad)] and since NO is a bidentate ligand, total ...
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Predicting the stability of coordination compounds using Crystal field theory

The question is this: On the basis of CFT, predict with justification which of the following two complex ions would be more stable [Mn(CN)6]4- or [Fe(CN)6]4-. Attempt at solution: Both the ...
3
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1answer
39 views

Order of filling electrons in Jahn-Teller energy diagram

When filling electrons in atomic or molecular orbitals we fill first the lower energy orbitals and then the higher, according to Pauli and Hund's rule. But this seem not to be the case when ...
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0answers
37 views

What is the difference between a dπ-dπ and delta bond [closed]

I have always been wondering the difference between a dπ-dπ bond and a delta bond. What are the situations that either bond is formed in overlap of two d orbitals.
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1answer
46 views

Why does Chem3D minimize nitrogen dioxide (radical) so badly? [closed]

I build from text O-N+O (the SMILES of this is O=[N+][O-]), I delete the hydrogen atom added automatically on N, then I start MM2 Minimization. Both the bond length ...
2
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1answer
82 views

Crystal field splitting of other orbitals

According to crystal field theory (CFT), $\mathrm{d}$-orbitals of central metal atom splits due to non uniform repulsion of ligands around the metal atom. Why isn't $\mathrm{p}$-orbital splitting ...
2
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1answer
24 views

Can o-phenanthroline be used as a complexing agent for lead(II)?

I’ve been trying to find a method to perform a spectrophotometric analysis to determine lead concentration (on the ppm level). This would require some chelator capable of forming a coloured complex ...
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0answers
28 views

Effect of optical isomerism on colour of transition metal complexes

I know that different stereoisomers of a given transition metal complex (cis- and trans- forms) have different colours. But do different optical isomers (non-superimposable mirror images) have ...
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1answer
55 views

Does tris(ethylenediamine)iron(III) exhibit optical isomerism? [closed]

I'm studying 12th. In my book they mentioned that $\ce{[Co(en)3]^3+}$ exhibits optical isomerism. But in that same book, there is a question Which of this doesn't exhibit isomerism? and the ...
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1answer
71 views

Is NH3 a strong ligand or weak? [closed]

Sometimes it produces high spin complex and sometimes low one. Is there any generalised result
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1answer
53 views

For group 13 elements M³⁺, why is the formation of MCl₄⁻ more favorable than for group 12 elements M²⁺?

I'm not a chemist and I'm trying to understand a chemistry point from a talk I went to recently. Any help would be much appreciated. The speaker was talking about $+3$ (Group 13) elements in the ...
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0answers
53 views

Why does the binding of DMSO to metal via the S atom (k-S) strengthens the S=O bond?

So, DMSO (dimethyl sulfoxide) can form metal complexes in both $\mathrm{\kappa O}$ and $\mathrm{\kappa S}$ mode i.e. binding with the oxygen or the sulfur respectively. The general explanation given ...
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2answers
520 views

What is the IUPAC name of [Cr(H2O)5Cl]Cl2.H2O [closed]

What is the IUPAC name of $\ce{[Cr(H2O)5Cl]Cl2.H2O}$? The net says that the correct name is Pentaaquachloridochromium(III) chloride. But do we not have to account for the water molecule present ...
2
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1answer
68 views

are there any stable four membered chelate rings?

With reference to coordination compounds, most chelate rings formed with the metal atom and ligands are 5-member rings (including the central metal atom), such as complexes with Oxalate, ...
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0answers
69 views

t2g and eg electronic configuration

I have been told that with the help of crystal field theory, we can decide the electronic configuration ($\mathrm{t_{{2g}}}$ $\mathrm{e_g}$ configuration) of the metal ion in a complex. For example, ...
0
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1answer
67 views

Will the following complex show optical isomerism

So there is this question which asks whether the following complex $\ce{[Co(NH3)4Br2]+}$ will show optical isomerism or not. According to my knowledge it will show optical isomerism in cis ...
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1answer
99 views

What is primary valency

This is from an adapted version of Concise Inorganic Chemistry by J.D Lee.The part on primary valency is confusing me.It mentions that primary valency is the oxidation of the central metal (a number) ,...
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1answer
143 views

Which hydrate isomer of [Cr(H2O)6]Cl3 have lowest electrical conductivity [closed]

I found this question in my book and the answer that was given is $\ce{[Cr(H_2O)_4 Cl_2]Cl.2H_2O}$ but I think it should be $\ce{[Cr(H_2O)_5 Cl]Cl_2.H_2O}$ because in this case only one $\ce{H_2O}$ ...
3
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1answer
266 views

Geometry of Ni(acac)2

The complex $\ce{Ni(acac)2}$ is paramagnetic as expected , i.e it has two unpaired electrons giving rise to a magnetic moment of $ \sqrt{8}$ BM but doesn't have the tetrahedral geometry consistent ...
5
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1answer
720 views

How does Potassium Hexfluoronickelate(IV) exist in a stable state?

Nickel generally does not exist in a $+4$ Oxidation state. Wikipedia has the following to say regarding Nickel(IV): Ni(IV) is present in the mixed oxide $\ce{BaNiO3}$. ....... Ni(IV) remains a rare ...
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2answers
164 views

Coordination number of chromium(III) oxalate complex

The coordination number refers to the number of binders that interact with the central metal ion. So, in the complex $\ce{[Cr(C2O4)3]^3-}$ chromium is bound to three oxalate ions. Why its ...
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1answer
561 views

How is the bonding in the [Au6C(PPh3)6]2+ cluster explained?

How can carbon form six bonds in such a compound as $\ce{[Au6C(PPh3)6]^2+}?$ I understand how carbon with five bonds can be formed $(\ce{CH5+},$ for instance), but it shouldn't have enough electrons ...
0
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1answer
253 views

What is the difference between cyanato, cyanido and cyano? When should i use which? [closed]

I understand that cyanido is the newly adopted naming in place of cyano but what is cyanato? Can anyone please give examples to illustrate the difference?
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1answer
137 views

Why is chromate coloured but tungstate colourless?

I have to try and work this out using the tetrahedral molecular orbital diagram for $\ce{[WO4]^2-}$ but I am confused as both are $\mathrm d^0$ right?
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0answers
24 views

Specific examples of all-main-group complexes with significant d-orbital contribution

It is usually said that d-orbitals are not usually used in bonding, even for so-called "hypervalent" ones, in compounds that are made purely of main group compounds. However, after reading an article ...
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1answer
284 views

Why is iron pentacarbonyl known, but iron(III) hexacarbonyl is not?

Why is the neutral complex $\ce{[Fe(CO)5]}$ known, but the cationic carbonyl complex $\ce{[Fe(CO)6]^3+}$ is not known?
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2answers
306 views

Predicting colors of aqueous solutions

While going through my AP chem prep book again, I came across questions asking about the color of certain aqueous solutions. For example: Which of the following substances will produce a colorless ...
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0answers
136 views

Definition of t2g orbitals in CFT

My textbook defines $\mathrm{t_{2g}}$ orbitals as $\mathrm{t_{2g}}$ stands for a set of three orbitals which are asymmetric with respect to $C_2$ axes, perpendicular to the highest $C_n$ axes, but ...
3
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3answers
245 views

Determining the oxidation state of a bridging platinum complex

I want to ask a question about determining the oxidation state of a Platinum complex. I was presented today with the following complex and asked to comment on the oxidation state and hence the d-...

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