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. ...

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What is the meaning of 'anion water' in coordination chemistry?

In Mechanisms of Inorganic Reactions by Fred Basolo and Ralph G. Pearson, a passage discusses the history of coordination chemistry. Ammoniates had been assumed to be analogous to hydrates. They ...
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42 views

Nature of Bond in Methylammonium lead Halide

I want to know about the nature of bond in Methylammonium Lead halide(CH3NH3PbX3),a perovskite compound.I went through wikipedia and many other sites and through certain research papers but I didn't ...
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0answers
48 views

d-orbital splittings in WS2 monolayer

The formely degenerate $d$ orbitals of the tungsten atoms in the $\ce{WS2}$ monolayer are split into three groups: (1) $\mathrm{d}_{z^2}$, (2) $\mathrm{d}_{x^2-y^2}, \mathrm{d}_{xy}$ and (3) $\mathrm{...
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0answers
94 views

Oxidation states of iron in Roussin's salts

For preservation of meat, sodium nitrite is usually added and as a result $\ce{NO}$ is, then,formed. Consequently, $\ce{NO}$ reacts with the sulphur and iron atoms from decomposition of proteins, ...
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1answer
83 views

Pi-acceptor Ligands

Which of the following are pi acceptor ligands? $\ce{PR3}$ $\ce{Cl-}$ $\ce{NH3}$ $\ce{H-}$ I know that $\ce{PR3}$ is a pi-acceptor, and that $\ce{Cl-}$ is a pi-donor ligand from my lectures. I am ...
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1answer
17 views

TM hydride chemical shift

Why is the chemical shift for hydrides in TM complexes so strongly shielded, to the point where it's negative? Initially, I thought it was because hydrides are $\ce{H-}$, but isn't the charge ...
2
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2answers
39 views

How to deduce crystal field splitting pattern

How do you determine the crystal field splitting pattern when given the structure of a complex? It's quite simple for structures like octahedral or tetrahedral, but I find that the reasoning behind ...
7
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1answer
178 views

Stability of ferrous ions and iron(II) hydroxide in acidic conditions

I was reading a chemisty textbook when I came across the following statement. $\ce{Fe(OH)2}$ is not stable, even more so in basic conditions. [---] $\ce{Fe^2+}$ ions are also less likely to ...
7
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1answer
41 views

Why doesn't the bidentate ligand form dative bonding three times?

I was looking at this question where it asked you to work out the final complex formed when an excess of 1,2-diaminoethane is added to and aqueous solution of copper (II) sulphate. So the equation I ...
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2answers
56 views

Na2CO3 + FeBr3 + H2O: why do we get Fe(OH)3?

$$\ce{3Na2CO3 + 2FeBr3 + 3H2O -> 6NaBr + 2Fe(OH)3 + 3CO2}$$ Why $\ce{Fe(OH)3}$? Where do these $\ce{-OH}$ groups come from? This is from a series of reactions in a Russian sample exam question. ...
3
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1answer
55 views

Semi-sandwich complex IUPAC name

I've tried looking here, but I can't figure it out. As a start, what is just the cobalt and cyclopentadienyl anion compound called. How does that name get added to the trimethylphosphine and carbonyl ...
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1answer
56 views

Hybridization of tetraamminecopper(II) sulfate

$\ce{Cu^2+} $ has 9 electrons and a d-orbital and is almost completely filled (except 1 electron vacant) and $\ce{NH3}$ donates an electron eventually forming $\mathrm{sp^3}$ hybrid orbitals. But it ...
2
votes
1answer
60 views

How to determine the magnetic character of heteroleptic complexes?

I was asked to find out the magnetic behavior (and essentially electronic configuration) of heteroleptic complexes using Valence Bond Theory and Crystal Field Theory. But I am confused about how to ...
2
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0answers
22 views

Why Fe(OH)2 and some precipitates do not dissolve in excess ammonia?

I understand that Cu(OH)2 can dissolve in excess ammonia because ligand exchange reaction occurs. But why ligand exchange reaction does not occur for Fe(OH)2?
8
votes
1answer
92 views

Bonding in alkali metal complexes

How exactly is the bonding described in complexes involving alkali metals? In particular, how much of a covalent component is there? Take three examples: $\ce{[Na(H2O)6]+}$: This previous answer by @...
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vote
1answer
69 views

Geometry of tetrabromidomanganate(II)

What is geometry and hybridization of $\ce{[MnBr4]^2-}$ for $\ce{Mn}$ ($Z = 25$)? I am not sure if it is tetrahedral or square planar. I assumed $\ce{Br}$ is a weak ligand and got its geometry to be ...
4
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1answer
61 views

How potassium ferrocyanide is coloured?

The colour of a complex compound is due to unpaired electrons. As per crystal field theory, $\ce{K4[Fe(CN)6]}$ has no unpaired electrons so it has to be colourless. But then why is it coloured?
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2answers
429 views

Why is manganese(II) coloured although the transition should be spin-forbidden?

In every basic coordination chemistry class, at some early point the crystal field theory and LFSE will be taught, explaining that there will be an energy difference between d-orbitals (typically ...
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1answer
35 views

How to know which kind of distortion takes place due to Jahn-Teller effect

I have gone through a few videos and a few articles (including Wikipedia's) about Jahn-Teller distortion effect and I'm not able to follow if there is a rule which governs which kind of distortion ...
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0answers
41 views

Unit cell question on determining compound stoichiometry of KCoS?

For 5(a) and 5(c), how are we determining that the answer is K4CoS4? I keep counting it and getting K2CoS2. We know that the K and the S ratio must be 1:1, but how can we count the Cobalt? . ...
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1answer
53 views

Why Does Coordination of Metal Ions Happen Anyways?

I've been studying coordination chemistry, but I still have a fundamental question about the area: why do transition metals even form coordination compounds, while main group metals do not? Why can't ...
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1answer
94 views

How to determine which parts of a formula are ligands in the given amminechloridoplatinum(IV) complexes?

$$\begin{array}{cc}\hline \textit{Formula of Complex} & {\textit{Rewritten Formula (showing the}\\\textit{ coordinating ligands)}}\\ \hline \ce{Pt(NH3)6Cl4} & \ce{[Ph(NH3)6]Cl4}\\ \ce{Pt(NH3)...
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1answer
51 views

Are labile tetrahedral [Mabcd] complexes optically active?

In the above mentioned complex, there is a chiral centre at the metal, and hence it seems the compound must be optically active. But my course notes say that the ligands keep on changing their their ...
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0answers
17 views

Order of Bonding in Nonaqeuous Hydrated Salts [duplicate]

In the chemical formula of a hydrated salt, such as $\ce{CuSO_4.5H_2O}$, is it implied from the format of the name that the the Copper (II) ion is ionically bonded to the sulfate, with water molecules ...
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22 views

Distinguishing beetween silver halides with ammonia [duplicate]

Could someone please explain how ammonia (preferably using chemical mechanisms) enable us to differentiate between the silver - halide precipitates?
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1answer
116 views

Does crystal field splitting energy Δ increase going down a group of transition metals if the ligands are weak field?

Going down a group, the metal orbitals are more diffuse so there is greter overlap between the metal and the ligand orbitals. If there are no π-interactions, i.e. with σ-donor ligands like $\ce{NH3}$, ...
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1answer
25 views

Electron counting in an ethenetriplatinate complex

In $\ce{[Pt_3(C_2H_4)]-}$, how many electrons are there around $\ce{Pt}$? While solving this problem I thought three $\ce{Pt}$ formed a triangle with ethylene above. But I was confused about how the ...
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0answers
23 views

HDEHP and complexes formed in extraction

I did an solvent extraction of Eu(III) using HDEHP from nitric and hydrochloric acid solutions to determine which acid, and which concentration, will yield the highest distribution coefficient. My ...
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1answer
55 views

Hydrogen bonding in complex compounds?

Does the water molecules in coordinated water (where water acts as ligand) form hydrogen bonding with other complex molecules? Will the water molecules inside the complex form intramolecular hydrogen ...
5
votes
1answer
107 views

Chromium complexes and nomenclature

In theory, $\ce{[Cr(H2O)6]^3+}$ ions have a bluish violet colour. However, many times in the lab we end up with a dark green solution. This is due to hydrolysis, coordination with sulphate (or other) ...
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2answers
54 views

Do the tetramminecopper(II) and hexathiocyanatoferrate(III) complexes obey the 18-electron rule?

Can anyone tell me whether $\ce{[Cu(NH3)4]^2+}$ and $\ce{[Fe(SCN)6]^3-}$ obey the 18-electron rule, and if not, why? I found $\ce{[Cu(NH3)4]^2+}$ and $\ce{[Fe(SCN)6]^3-}$ have 17 electrons, was I ...
4
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0answers
62 views

Dsp2 and sp3: coordination chemistry

Why is dsp2 square planar but sp3 tetrahedral in shape? I am unable to find a reason anywhere. I know how to figure which hybridisation a compound is, but not why.
4
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1answer
51 views

Question about energy of orbitals under a crystal field

It is shown in octahedral crystal field splitting that both the $e_g$ orbitals have equal energy. But how can that be possible ? The $d_{x^2-y^2}$ is directed along both the axes (x and y) whereas ...
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40 views

How do we see coordination complex colors?

The color of a coordination complex can be predicted using the Crystal Field Theory. The basic principle involved in this is that complexes absorb certain wavelengths of light and transmit the other ...
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0answers
47 views

Does complex formation lead to increase in freezing point?

Original question:- When mercuric iodide is added to an aqueous solution of Potassium iodide, freezing point increases. Why? Answer given:- Due to formation of Complex $\...
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0answers
23 views

why aluninum containers can't fill solution with Cl-

It is said that $\ce{Cl^-}$ will corrode Aluninum containers. Why? Is it because form galvanic cell or produce coordination compounds?
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2answers
143 views

Why doesn't tetrachloridotitanate(II) obey the 18-electron rule?

I have worked out that the complex comes to 10 electrons, however I do not understand why it does not obey the 18-electron rule? What are the factors that account for this?
5
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1answer
52 views

Isomers of Octahedral Coordination Compound with Two Bidentate Ligands

Draw all possible isomers of $\ce{[CoNO_2(en)_2NH_3]^{+}}$ I reckon that there are 4 isomers, as drawn above. Am I correct?
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2answers
223 views

When are the prefixes bis, tris etc. used in nomenclature of complexs?

Are the prefixes bis-, tris- etc. used only for ligands that are bidentate in complex nomenclature?
2
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2answers
83 views

Confusion about the oxidation state of copper in copper cyanide redissolved with excess cyanide

$\ce{CuSO4}$ when reacts with $\ce{KCN}$ forms $\ce{CuCN}$ while it is insoluble in $\ce{H2O}$. It is soluble in excess of $\ce{KCN}$ due to the formation of the following complex: a) $\ce{K2[Cu(...
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45 views

How many electrons will it donate?

I went through a question about the EAN rule. At first, it was all clear to me , but now I'm just confused on how to decide which ligand will donate how many electrons. How do we decide which kigand ...
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1answer
543 views

What is the IUPAC name of [Co(NH3)5H2O]Cl3?

I am not getting if it is Pentaammineaquo cobalt(III) chloride or Aquopentaammine cobalt (III) chloride-should the prefix be ignored while naming the ligands in alphabetical order? Besides how should ...
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3answers
176 views

How can I understand the Lewis acid-base interaction of iron(III) and water?

The interaction between $\ce{H+}$ and $\ce{NH3}$ as respectively a Lewis acid and a Lewis base is clear for me. $\ce{NH3}$ has a lone electron pair and $\ce{H+}$ has no electrons, or, saying politely, ...
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1answer
75 views

Hybridisation of hexaamminecobalt(III) complex [duplicate]

Does $\ce{[Cr(NH3)6]^3+}$ have $sp^3d^2$ or $d^2sp^3$ hybridisation? Oxidation state of $\ce{Cr}$ is $+3$. The electronic configuration is $3d^3$ and the $d$ electrons occupy $t_{2g}$ orbitals. If ...
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0answers
30 views

How do partially protonated sulfate ligands affect a metal's charge?

I'm currently reviewing the Periana-Catalytica system and I have a question about one of the intermediates, namely $\ce{[(bpym)Pt(OSO3H)2]^+}$, which is found in the following tutorial review. How do ...
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1answer
53 views

Isomers of co-ordination compounds

Does $\ce{[Co(H2O)3Br3]}$ show geometrical and optical isomerism? According to me $\ce{Co}$ should be $\mathrm{sp^3d^2}$ hybridised giving an octahedral geometry. It is of the form $\ce{Ma3b3}$ type. ...
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1answer
118 views

Isomers of coordination compounds

Does [Pt(CH3-CH(NH2)(COO-))2] show geometrical and optical isomerism? According to me Pt should be dsp2 hybridised giving a square planar geometry. So it is of the form M(aa)2 type. The ligand ...
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14 views

Is it possible to quantify the effects of a chelating agent?

If one wants to see what compound is a more effective chelating agent, how does that get measured?
3
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1answer
153 views

Metal carbonyl bonding

I have been going through this topic in my coordination chemistry chapter. I read that in metal carbonyls, -CO group acts as ligand and donates its lone pair of electrons into a vacant orbital of the ...
4
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1answer
128 views

How does complex ion differ from ligand complex?

As I understand, in terms of "colouring", ligand complex cause a transition metal cation centre's d-shell to split, allowing the electrons in that region to absorb specific frequencies of light, and ...