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.

Filter by
Sorted by
Tagged with
1
vote
0answers
11 views

Why does thiocyanate bind to Fe³⁺ with the S side instead of the N side?

According to hard and soft acids and bases (HSAB) theory, "soft" Lewis bases bind to "soft" Lewis acids, and "hard" Lewis bases bind to "hard" Lewis acids. $\ce{Fe^3+}$ is a hard Lewis acid. In $\ce{...
1
vote
0answers
7 views

Energy diagram of copper iodide complex

We did an experiment where copper iodide 4-methylpyridine and copper iodide imidazole was formed and now we are asked what orbital the electron is excited from and to. After much research we still ...
-3
votes
0answers
27 views

Complex compounds [closed]

[PPh4][PF6] can you please explain how to get that compound (getting reaction), and how will look the dissociation equation. I know that [PPh4] is tetraphenylphosphonium chloride (PH4 is phosphonium) ...
2
votes
1answer
21 views

Ligand substitution reaction in coordination compounds

I know that the following substitution reaction can take place: $$\ce{[Cu(H2O)4]^2+ (aq) + 4NH3 (aq) -> [Cu(NH3)4]^2+ (aq) + 4H2O (l)}$$ This is because ammonia is a stronger ligand than water. ...
-3
votes
0answers
24 views

Homework in chemistry [closed]

How we can get that Ca[Cu(SCN)4] (getting reaction)? And can you hepl me with dissociation equation for this complex?
0
votes
0answers
21 views

Benzannulation of 18-crown-6

I know crown ethers can be used to complex metal ions. Question: What important properties do 18-crown-6 change during the benzannulation from 18-crown-6 to DB18C6 (dibenzo-18-crown-6)? How do these ...
-1
votes
0answers
18 views
1
vote
1answer
30 views

Naming a coordination compound

I was asked to determine the coordination compound which has the name: $$\text{triamminetrinitritocobalt(I)}$$ I thought it must be: $$\ce{[Co(NH3)3(ONO)3]^2-}$$ The $-2$ charge can be deduced by ...
-1
votes
1answer
48 views

Why is the solution of (NH4)2[Ce(NO3)6] used as an oxidizing agent? [closed]

In an MCQ, the correct statement regarding the abovementioned compound is that its solution is used as an oxidizing agent. I do not understand why that is so.
1
vote
0answers
26 views

Counterion exchange

I have a quick question about counterion exchange. I have this very practical problem at my hands that I have a ethyl sulfate $(\ce{EtSO4-})$ counterion for a $\ce{R4N+}$ moiety ($\ce{R}$ = 3 ...
4
votes
2answers
288 views

Chromium cyanide complexes

I have rarely seen any chromium $(\ce{Cr})$ square planar complexes and I have been told that $\ce{[Cr(CN)4]-}$ is tetrahedral. So, if the statement is actually correct, are there any other known ...
0
votes
0answers
44 views

Why is [NiCl2(PPh3)2] tetrahedral and [NiCl2(PMe3)2] square planar? [duplicate]

I'm confused here since PPh3 is a strong field ligand and would try to make the molecule square planar but is bulky and would tend to adopt tetrahedral geometry to minimise sterric hindrance. And why ...
-1
votes
1answer
73 views

Confused on how to draw cis-[Ni(H2O)4(NH3)2]Cl2 [closed]

I got a question on my practice exam telling me to draw cis-diamminetetraaquanickel(II) chloride, but I'm not sure on how to place the two $\ce{Cl}$ atoms.
0
votes
1answer
33 views

Isomerism and namegiving

Is this the right chemical formula of the $\ce{Rb[Pt(NH3)Br2Cl]}$ complex: rubidium amminedibromidochloridoplatinate(II)? And is it correct that it has geometric isomerism, being square planar with a ...
8
votes
1answer
64 views

Should we expect Jahn–Teller distortion in bis(ethylenediamine)nickel(II)?

(ii) The stepwise stability constants of the following complexes in aqueous solution at $\pu{25 °C}$ are given below: $$ \begin{array}{cll} \hline \ce{M} & \ce{[M(en)2(H2O)2]^2+} & \ce{[M(...
0
votes
0answers
32 views

Why do statistical effects impact stepwise stability constants?

I have a question regarding the stepwise stability constants of metal complex formation/substitution. My lecture notes say that if we have a metal complex, say $\ce{[MX_{6}]}$, and a substitution ...
1
vote
0answers
25 views

Stability order of chelate complexes of nickel and iron

Which stability order is correct? $\ce{[Ni(en)2]^2+} > \ce{[Ni(dmg)2]}$ $\ce{[Fe(edta)]^2-} > \ce{[Fe(en)3]^3+}$ In the first case I think the stability depends upon the strength ...
1
vote
0answers
43 views

What is the order of crystal field stabilisation energy for tris(ethylenediamine)chromium(III) chloride and hexaaquachromium(III) chloride?

In my book it is given that the crystal field stabilisation energy for $\ce{[Cr(en)3]Cl3}$ is more than that of the complex $\ce{[Cr(H2O)6]Cl3}.$ By what I have studied, the crystal field ...
1
vote
0answers
26 views

Why CO is a weak pi-acid ligand?

This question was given by my chemistry professor, but I doubt that this question is not correct. Following the lewis definition of the acid, any molecule or atom acts as a acid if it accepts an ...
0
votes
1answer
43 views

Why is dimethylglyoximate a bidentate ligand and not a tetradentate ligand?

Why can't the 2 oxygen atoms donate a lone pair and hence become binding sites? Is it because of the angle made by the oxygen and Nitrogen atoms?
1
vote
1answer
62 views

Optical activity of cis coordination compounds

I came across a statement saying, "Consider a Octahedral coordination compound of type [MA2X2]. Then, if the compound is in a cis form, it shows optical activity as there is no plane of ...
1
vote
3answers
60 views

Which would have a more intense transition: a low spin d6 complex or a high spin d5 complex?

I have an assignment question for second year inorganic which asks to rank the intensity of d-d transitions for a number of complexes. Two are $\ce{[Fe(OH2)6]^3+}$ and $\ce{[Fe(CN)6]^4-}.$ Both will ...
6
votes
1answer
128 views

Ionization isomerism in coordination compounds

Ionization isomerism is defined as complexes which have same empirical formula but ionize to different ions in solution. Consider the complex $\ce{[Pt(NH3)4Cl2]I2}$. The other possible ionization ...
-3
votes
2answers
57 views

Relation between the oxidation state of central atom and its coordination number in a complex compound? [closed]

We know for a complex say $\ce{[Co(NH3)3Cl3]}$ we have $\ce{Co^{3+}}$ and its coordination number here is 6. And for this if we know either oxidation state or coordination number then other is fixed. ...
2
votes
0answers
34 views

What's an appropriate ligand for Pd-Ag redox?

I want to reduce palladium with silver (in cellulose): $\ce{Pd^{2+} + 2Ag->2Ag+ +Pd}$. What is a good ligand and spectator ion for both metals? (The pH is not critical.) Ones I have considered: $\...
2
votes
0answers
29 views

Will disodium EDTA effectively destroy Tollens' reagent?

As I understand it, if I mix $\ce{[Ag(NH3)2]NO3}$ and $\ce{Na2EDTA}$ the silver will complex much more strongly with the EDTA than the ammonia, and the hydrogen ions will protonate the ammonia, ...
3
votes
1answer
43 views

Sulfate and carbonate ions as ligands

The pentahydrate salt of copper (II) sulfate exists as a blue solid while the anhydrous and monohydrate salts appear as white solids. The structures of these salts are discussed here. The blue colour ...
3
votes
0answers
57 views

Reaction between Sodium Thiosulfate and Iron Chloride

I'm doing a paper on catalytic effectiveness in this reaction, and am trying to identify how the catalysts are speeding up the reaction. Based on what I can find, $\ce{Fe}$ starts as $\ce{Fe^3+}$, ...
0
votes
1answer
35 views

About Fe(III) and Fe(II) coordination complexes

Why does Fe(III) form octahedral coordination complexes if it has 5 electrons in its d-orbitals? I understand that Fe(II) has 6 electrons in its d-orbitals and 6 lone pairs from 6 ligands as the 12 ...
11
votes
4answers
2k views

Explanation for why nickel turns green in hydrochloric acid

My daughter has a chemistry test that I am helping her prepare for. One question is Nickel sulfate, $\ce{NiSO4(aq)}$ is a green solution. Nickel chloride, $\ce{NiCl2(aq)},$ is a yellow solution. If ...
2
votes
1answer
54 views

Formation of green precipitation whilst adding potassium fluoride to aqueous solution of copper(II) sulfate [closed]

Aqueous copper sulfate solution (blue) gives a green precipitation with aqueous potassium fluoride. Explain these experimental results. I've read answers like, $\ce{H2O}$ is a weak ligand and ...
1
vote
1answer
119 views

Magnetic nature of tetraamminedichlorocobalt(III) chloride

I know how to predict magnetic nature when the compound contains only strong field or only weak field ligands. But in $\ce{[Co(NH3)4Cl2]Cl},$ $\ce{NH3}$ is a strong ligand whereas $\ce{Cl-}$ is a weak ...
0
votes
0answers
98 views

Changes in conductivity of CuSO4 solution after NH3 solution is added

In my high school chemistry class we are writing a lab. Originally, I wanted to measure the rate of a ligand exchange reaction at different temperatures by measuring changes in conductivity. After ...
1
vote
1answer
30 views

Is it important to use arrows as bonds in writing coordination compounds? [closed]

Why are the coordination compounds representated by arrows? Is it necessary to write every coordination compounds with the arrow side of the bond facing the metal ion and the other part the ligand?
2
votes
1answer
70 views

Why there are more examples of carbonylate anions than metal carbonyl cations?

I know that metal carbonyl complexes that do not follow EAN rule or 18 electron rule try to achieve that by gaining electron (forming carbonylate) or loosing electron (forming carbonyl cations). But ...
0
votes
1answer
76 views

Software that determines whether a molecule can exist and draw it from a formula?

I have run calculations that predict atomic configurations. As a simple example, in a system that contains H and O, I might get a list like: ...
0
votes
1answer
39 views

What is the binding mode of the ligand in complexes with quadruple metal-metal bonds?

I'm wondering which atomic orbital is left in a complex with quadruple metal-metal bond to bind the steric ligand, since all d orbitals except the x2-y2 are used for the metal-metal bonds? or is it ...
0
votes
0answers
56 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 ...
1
vote
0answers
131 views

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 ...
2
votes
0answers
66 views

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 ...
1
vote
1answer
86 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?
4
votes
1answer
507 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 ...
1
vote
0answers
24 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'...
1
vote
0answers
38 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 ...
1
vote
0answers
52 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 ...
1
vote
0answers
36 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 ...
1
vote
1answer
178 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 ...
0
votes
1answer
97 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 ...
-1
votes
1answer
79 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.
1
vote
0answers
43 views

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 ...