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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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Toxicity of Mercury (II) Iodide and dicopper (I) tetraiodomercurate (II)

This is a continuation from my previous post. Could you please give me some info on the toxicity of compounds $\ce{HgI2}$ and $\ce{Cu2[HgI4]}$? I found on sigmaaldrich.com that these are very ...
AntonPeganov's user avatar
2 votes
0 answers
44 views

Chemical properties of dicopper (I) tetraiodomercurate (II)

This is a continuation from my previous post. Where can I find information on the chemical properties of $\ce{Cu2[HgI4]}$? I found a mention that in reaction with $\ce{Na2S2O3}$ in presence of acid ...
AntonPeganov's user avatar
4 votes
0 answers
118 views

How to use Sodium Thiosulfate for fixing dicopper (I) tetraiodomercurate (II)?

DISCLAIMER DO NOT TRY TO DEMERCURATE USING DESCRIBED PROCEDURE. CONSULT YOUR EMERGENCY SERVICE. I found a discrepancy between a government-approved procedure of living quarters demercuration and the ...
AntonPeganov's user avatar
0 votes
0 answers
70 views

Equilibrium of zinc ion with ammonia

In my chemistry lab, we are testing the amphoteric properties of this metal. I understand zink can react with an acid or a base to form different compounds in solution based on pH. In one part of the ...
DJames's user avatar
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1 vote
0 answers
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In the aquation of cis-platin, why are the chloride ligands, and not ammonia, replaced with water, despite chloride's larger trans effect?

https://doi.org/10.1021/ic000847w In this paper, the aquation of cisplatin is examined. When used to treat cancer, the chlorides are substituted with water molecules, which seems to go against the ...
Jonathan Lee's user avatar
13 votes
3 answers
578 views

Comparison of C=O bond strength in metal carbonyls

Find the weakest $\ce{C=O}$ bond among $\ce{[Mn(CO)6]+},$ $\ce{Fe[(CO)5]},$ $\ce{[Cr(CO)6]}$ and $\ce{[V(CO)6]-}.$ I thought the $\ce{C=O}$ bond strength would be lowest in $\ce{[V(CO)6]-}$ since the ...
m-Xylene's user avatar
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0 answers
98 views

Entropy and Gibbs Free Energy of Chelate Complexes

Of [Cd(NH2CH3)4]2+ and [Cd(en)2]2+ the stability of the latter is higher than the former attributing to chelation in the en complex .This is evident from the fact that the Gibbs Free Energy change for ...
PV.'s user avatar
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2 votes
0 answers
459 views

Comparing bond lengths in metal carbonyls

Question: It's solution is given as: Now I don't understand which d$\pi$ electrons have been considered here. For example, in $\ce{Fe(CO)_5}$, according to this, number of d$\pi$ electrons would be ...
V.G's user avatar
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1 vote
2 answers
293 views

Is glycinate ligand a monoanion or a zwitterion?

Glycinate as far as I can guess from the structure is a monoanion with negative charge on oxygen atom (though that negative charge is resonating). But when I used this logic in my exam it costed me 4 ...
ANONYMOUS AE's user avatar
0 votes
1 answer
397 views

Octahedral, Tetrahedral or Square planar? [closed]

In cases where a metal ion like, Fe(III), Cr(III), Pt(II) is made to react with a ligand species like oxalate, CN-, CO etc and it forms a complex then, How do we determine whether 6 ligands will be ...
Ashish's user avatar
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1 vote
2 answers
185 views

Why transition metal chloride complex have lower reduction potential than metal aqua ions?

Why transition metal chloride complex have lower reduction potential than metal aqua ions? For example: $$ \begin{align} \ce{Au^3+(aq) + 3 e- &-> Au(s)} &\quad E^\circ &= \pu{+1.52 V}\...
Alessia's user avatar
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4 votes
1 answer
5k views

IUPAC name of H[AuCl4]

Is $\ce{H[AuCl4]}$ tetrachloroauric [III] acid or hydrogen tetrachloroaurate[III]? As per the rules I have studied the latter name is correct. Then why am I getting the former name mentioned ...
ANONYMOUS AE's user avatar
5 votes
0 answers
347 views

Why does beryllium have an exceptionally high hydration energy?

You would expect solubility of Group $2$ fluorides to increase down the group, as lattice energy plummets much more sharply than hydration energy does. For the most part, this is true: $\ce{BaF2}$ is ...
Ray Bradbury's user avatar
4 votes
1 answer
221 views

Why is hydrated beryllium ion acidic?

The beryllium ion, $\ce{Be^{2+}}$, forms the aquo complex $\ce{[Be(H2O)4]^{2+}}$. According to LibreTexts, this complex is acidic in solution: $$\ce{[Be(H2O)4]^{2+} + H2O -> [Be(H2O)3OH]+ + H3O+}$$ ...
Ray Bradbury's user avatar
2 votes
2 answers
3k views

Are high spin complexes and spin free complexes the same thing?

While solving some Coordination Compounds problems, I came across a problem that asked Select which complex is high spin or spin free octahedral complex. The term 'spin free' sounds like a complex ...
Aniruddha's user avatar
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3 votes
0 answers
145 views

Why is tetrachlorocuprate (II) yellow if it is high-spin?

From my knowledge of transition metal complexes, tetrahedral complexes generally have less splitting (compared to octahedral complexes) because they only involve four ligands are they aren't placed ...
chematwork's user avatar
1 vote
1 answer
768 views

How does the anti-bonding eg orbital (eg*) affect the bonding of ligands?

In the molecular orbital for octahedral metal-ligand complexes, there is an eg orbital and an eg* orbital. When the d orbitals on the metal split, it will fill up some of the eg* orbitals I believe. ...
M.L's user avatar
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1 vote
2 answers
154 views

Why iron(II) spectrometry is not measured in distilled water and it requires a complexing agent like o-Phen?

We know that iron(II) ions in water have a green colour. Why we cannot draw the spectrum of iron(II) directly in distilled water to measure the absorbance then determine the concentration of iron(II)? ...
Gougni Adam's user avatar
0 votes
0 answers
194 views

Why does π-backbonding in a metal-carbonyl complex lead to a decrease in C-O bond strength?

I understand that π-backbonding in this complex involves the σ-donation of carbonyl to an empty d orbital of the metal, and the π-donation of the d electrons of the metal to the π* MO of the carbonyl. ...
user105141's user avatar
-4 votes
2 answers
145 views

What exactly is hydrolysis? What are the products of hydrolysis of aluminium?

I came across three reactions while studying p-block compounds in inorganic chemistry. $$\ce{2Al + 2NaOH + 6H2O -> 2 Na[Al(OH)4] + 3H2} \label{eq:1} \tag{1}$$ $$\ce{Al2O3 + 2NaOH + 3H2O -> 2 Na[...
Adeebjarvis's user avatar
3 votes
1 answer
269 views

EDTA titrations of singly charged cations

It is well known that EDTA can be used for titrations involving complexations of highly charged metal cations, with the most well known being those of the alkali earth metals and transition metals. ...
timeinbaku's user avatar
1 vote
1 answer
743 views

Is the Co-ordination number of Cobalt always 6 in every co-ordination compound?

For example in the following compounds CoCl3.6H2O CoCl3.6NH3 CoCl3.5NH3 CoCl3.4NH3 in all of these complexes, we took the a)oxidation state of Cobalt as +3 ( since there are 3 Cl- ions and NH3 and ...
Tanya Gupta's user avatar
1 vote
0 answers
557 views

Strength of Pi Donor and Acceptors as Ligands

The spectrochemical series is usually known as the "strength" of the ligands. It makes sense on a basic level as the more willing a ligand is to donating its electrons (via a $\sigma$-bond), ...
chematwork's user avatar
8 votes
1 answer
6k views

Why are complexes of type MA3B3 not optical active?

Complexes of type $\ce{MA3B3}$ have two geometrical isomers, namely: fac-isomer mer-isomer If we look closely at the mer-isomer, it has a plane of symmetry, so it is optically inactive. But the fac-...
Harsh's user avatar
  • 111
-1 votes
1 answer
419 views

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 ...
A.Hany's user avatar
  • 41
0 votes
2 answers
981 views

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?), ...
Moe Hussein's user avatar
3 votes
0 answers
304 views

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 ...
XisUnknown's user avatar
-3 votes
2 answers
106 views

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 ...
Arnav's user avatar
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3 votes
0 answers
1k 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^-...
JulianS's user avatar
  • 111
7 votes
2 answers
579 views

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, ...
bud's user avatar
  • 460
2 votes
0 answers
2k 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 ...
Fractal's user avatar
  • 402
0 votes
1 answer
773 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 ...
newbie105's user avatar
  • 397
0 votes
1 answer
101 views

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 ...
S RM's user avatar
  • 75
2 votes
1 answer
155 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 ...
Siddharth Bisht's user avatar
2 votes
2 answers
266 views

Colours in Coordination Compounds

I have read that $\ce{NH3}$ acts as an SFL with a $\ce{M^3+}$ metal ion and acts as a WFL with a $\ce{M^2+}$ metal ion. It also states that when $\ce{NH3}$ forms a complex with the $\ce{M^2+}$ ion, ...
Siddharth Bisht's user avatar
2 votes
1 answer
741 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 ...
SJY's user avatar
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3 votes
0 answers
422 views

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 ...
Enric Ros's user avatar
1 vote
1 answer
320 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 ...
user avatar
3 votes
1 answer
277 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 ...
Jabbamanga's user avatar
1 vote
0 answers
1k views

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 ...
TheLearner's user avatar
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1 vote
0 answers
223 views

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 ...
Informal Limits Lad's user avatar
0 votes
1 answer
2k 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, ...
Muhammed Rishan's user avatar
2 votes
0 answers
148 views

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 ...
Coyazayo's user avatar
0 votes
1 answer
1k 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 ...
Karan Nagrale's user avatar
0 votes
1 answer
3k 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 ...
the_amazer's user avatar
0 votes
1 answer
368 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 ...
pinkUnicorn999's user avatar
2 votes
1 answer
89 views

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 ...
Kent de los Reyes's user avatar
1 vote
0 answers
31 views

Determining the number of triphenylphosphine ligands in nickel(II) complex

A complex is synthesised by combining hydrated solutions of $\ce{NiCl2}$ $(\pu{0.6 g})$ with $\pu{1.35 g}$ triphenylphosphine $(\ce{PPh3}).$ After cooling the product precipitates as a solid with ...
user avatar
2 votes
0 answers
207 views

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 ...
Railgun's user avatar
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3 votes
0 answers
537 views

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 ...
user95979's user avatar

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