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Questions tagged [transition-metals]

For questions about the characteristic physical properties, chemical reactions, etc. of d-block elements, group 3-12, or their compounds. Do not use this tag if your questions is about general properties of metals, use [metal] instead. Also see [rare-earth-elements].

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2answers
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Why does copper(II) carbonate decompose into copper(II) oxide rather than copper(I) oxide when heated?

I recently did a lab at school surrounding the decomposition of copper(II) carbonate into copper(II) oxide, and subsequently into pure copper, when sufficient heat is added. What I don't understand is ...
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2answers
2k views

How can we predict the colour of transition metal complexes?

I am facing problems in indentifying colour of complex compunds just by seeing the their molecular formula. Is there any method or concept to predict the colour of complex compunds?
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1answer
155 views

Does mercury chloride (ii) evaporate at room temperature? [closed]

if you leave mercury chloride (ii) exposed to air in a room does it evaporate to any significant level which can cause toxicity?
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1answer
122 views

How is dioxygen stabilised by coordination to haemoglobin?

I wonder how the binding of $\ce{O2}$ to a molecule of hemoglobin stabilizes it to the extent that I can carried around the body with the risk of it being involved in oxidation reactions minimized. ...
6
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1answer
555 views

Why does Mn (II) behave as “hard”?

Why, within HSAB, does $\ce{Mn^{2+}}$ behave as a hard acid? If we go across the third block, then all metals to the left of manganese form soft divalent cations (e.g. $\ce{Ti^{2+}}$, $\ce{V^{2+}}$, $...
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1answer
144 views

Manganates (II)

I want to ask about character of manganese(II) compounds. I read that $\ce{MnO}$ is basic, just like $\ce{Mn(OH)2}$. I started doing research and I read ions like $\ce{MnO2^{2-}}$ and $\ce{HMnO2^-}$ ...
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0answers
132 views

Wilkinson's catalyst: why this structure?

I wonder how the structure of Wilkinson's catalyst contributes to its catalytic properties. For example, what role do the phosphine ligands play? What properties make Rh the best TM centre? Thank ...
1
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1answer
894 views

How many d-electrons are in the outer shell of metals like Cadmium (this is counting the 4d electrons)?

First I know similar questions have been asked about counting d-electrons. However, my question is about the electrons in the 4d orbital. For example if I have CdS. The cadmium has a charge of +2. ...
2
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1answer
417 views

Low-spin / high-spin arguments: why overlooking pairing energy?

There are many arguments in inorganic chemistry based on a transition from a high-spin to a low-spin configuration, for example: $K_{f,3} > K_{f,2}$ for $\ce{Fe(bipy)3}$ complex, because of "a ...
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320 views

Why is cupric oxide more basic than cuprous oxide?

I have learnt earlier that metal oxides with higher metal oxidation states are more acidic than those with less oxidation states, but copper disobeys this rule. Why?
3
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1answer
188 views

Spectrochemical series of TMs: why does the field-splitting parameter NOT steadily increase along a period?

Why doesn't the field splitting parameter increase steadily along the period for 3rd-row transition metals, as one would expect due to a better energy match between ligands and the metal as $Z_\mathrm{...
2
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2answers
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Why does ligand exchange take place? [closed]

Why does ligand exchange happen? Are there specific factors that determine when a ligand can replace another ligand? When ligand exchange takes place, does that mean that the "previous" ligand is ...
2
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0answers
55 views

CF and MO theories: seeing connections between the two approaches

I wonder if and how when considering MO theory, we are accounting for the electrostatic interaction / repulsion between electrons on the metal and the ligand. It seems like MO assumes pure covalency, ...
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2answers
1k views

Pattern to determine the maximum ionic charge for transition elements?

According to my textbook, main group elements follow a simple pattern when determining their maximum ionic charge. The maximum cationic charge is always equivalent to their main group number (group ...
6
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1answer
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If the ferric ion is more stable than the ferrous ion, then why is it readily reduced to the latter?

The standard reduction potential value for the Ferric ion: \begin{align} \ce{Fe^3+ + e- &<=> Fe^2+} & E^\circ &= 0.77 \end{align} The value is positive, hence it means that ferric ...
6
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1answer
178 views

Symmetry and SALC: choosing coordinate basis

When we construct symmetry adapted linear combinations of orbitals (aka SOs) to build an MO diagram, we choose the z axis as the axis of highest symmetry and all other axis to make symmetry operations ...
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2answers
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Why do heavier transition metals show higher oxidation states?

In p-block elements, higher oxidation states are less stable down the group due to the inert pair effect. This is not the case for transition metals. Why do heavier transition metals show higher ...
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0answers
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Removal of nickel plating on MgB2 without damaging the boride?

I need to remove a nickel plating of a MgB2 wire without causing damage to the MgB2. I felt that electrolysis is the best method but I do not know what electrolyte to use for this. I also need to coat ...
5
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0answers
2k views

Why does reduction of naphthalene with nickel/hydrogen lead to trans-decalin?

Is there any reason why $\ce{H2/Ni}$ leads to trans-decalin? I knew from high school that catalytic hydrogenations are always syn.
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3answers
2k views

What is CuCl.CO.2H2O?

What is the chemical $\ce{CuCl.CO.2H2O}$, formed via the reaction of copper chloride and carbon monoxide? Does this compound have any use or appear in any noteworthy reaction?
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1answer
578 views

Atomization enthalpies of transition elements

So, my book says that transition elements have higher enthalpies of atomization than other elements (say s- or p- block) because of stronger metallic bonding, primarily due to large number of unpaired ...
3
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0answers
128 views

Do amino groups need to be protected during a Clemmensen reduction?

In class, we learned about the Clemmensen reduction of carbonyl groups to the corresponding hydrocarbon. This is all well and good, except that it would also seem that the conditions used in the ...
8
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1answer
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Changing iron(III) acetate to iron(II) acetate

Is there a way simple way to turn iron(III) acetate into iron(II) acetate or vice versa? Edit (as per answer below): an oxidiser like hydrogen peroxide will turn iron(II) acetate into iron(III) ...
3
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Are there any stable complexes where an (N-unsubstituted) imine is bound eta^2 to a (late) transition metal?

I've been looking for an example of a stable complex where a $\ce{C=N}$ is coordinated $\eta^2$ to a (late) transition metal, but could not find any. Do they exist at all? For $\ce{C=C}$ there are ...
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0answers
102 views

What is the structure of diferric hexaphenolate?

I was studying about the ferric chloride identification of phenol, where one product formed is diferric hexaphenolate. But I am having trouble drawing out the structure of it. With ferric ion having a ...
2
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1answer
687 views

How can I dissolve nickel(II) oxide?

To insulate $\ce{Pt}$ wire heaters, I plated them with $\ce{Ni}$. After switching on the heater for the first time, green $\ce{NiO}$ is formed which is insulating and protects the $\ce{Pt}$ from ...
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1answer
3k views

Why does the Co³⁺/Co²⁺ couple have such a high reduction potential?

Cobalt is changing from $\mathrm{(3d)^6}$ to $\mathrm{(3d)^7}$ electronic configuration. What's so stabilizing about that? Just by reduction potentials this couple is more oxidising than hydrogen ...
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1answer
846 views

Fe with different charges

Taken these reactions: \begin{align} \ce{2\overset{0}{Fe} + 3Cl2 &-> 2\overset{+3}{Fe}Cl3} \tag{1}\\ \ce{\overset{0}{Fe} + 2HCl &-> \overset{+2}{Fe}Cl2 + H2} \tag{2} \end{align} Why ...
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1answer
8k views

Derivation of the Orgel diagram for octahedral d2 complexes

The Orgel diagram for a typical octahedral $\mathrm{d^2}$ complex is shown below: (source: Kettle, Physical Inorganic Chemistry, p 146) I understand that the right-hand half of the graph shows how ...
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4answers
30k views

Why are there 14 electrons in the third shell of iron atom?

The third shell must contain at least 18 electrons. But in iron there are 14 electrons in third and 2 electrons in 4th. Why are there 14 electrons in the third shell of iron atom?
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1answer
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How to find the oxidation state of complexes with bridging ligands? [closed]

How can I find the oxidation states of $\ce{Fe, OH-, NH2-}$ in the given complex?
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1answer
4k views

How do you determine the hybridisation state of a coordinate complex?

If an exercise asks for the hybridisation state of a coordinate complex (ion in solution) consisting of a central cobalt atom surrounded by $\ce{NH3}$ ligands, and neither coordination number or ...
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1answer
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How do I find the ground state term symbol for transition metal complexes?

I have a problem where I'm trying to match metal complexes with the proper ground state term symbol. I've tried doing a Google search and looking for a process, but haven't had any luck. I decided ...
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0answers
3k views

Is iron(III) carbonate stable in water?

I searched for this onsite already, and also found the following answer on Quora: In aqueous environment, iron(III) is bound by water molecules and exists as $\ce{[Fe(H2O)6]^3+}$. Due to strong ...
2
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1answer
633 views

Why is the iron(II) on the heme molecule depicted as having 6 electrons in its 5 d non- and anti-bonding orbitals?

Approximating the $\ce{Fe}$ complex as a square base pyramid ($D_\mathrm{4h}$ symmetry) with 5 $\ce{N}$ ligands, My electron count of the system gives me 16 electrons – 10 from the $2\times 5$ $\ce{N}$...
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0answers
325 views

Are d electrons ever delocalized in metallic bonding

It has been my understanding that delocalized electrons that participate in metallic bonds come from the highest primary energy level, specifically from the s and p sublevels and that electrons in d ...
5
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0answers
160 views

I found transition states (TS), but calculations aren't supported by experiment. Do I look for more TSs or somewhere else?

I'm using Gaussian to investigate a catalyst system. Experimental evidence showed that one of three analogues (R = phenyl, Ph), yielded a benzosultam when treated with 2,4,6-...
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1answer
3k views

What exactly is the d-orbital splitting and how does this affect the colors for transition metal compounds?

How does d-orbital splitting form colors for transition metals? Why can't the electrons in the d-orbital split for the element Zinc?
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0answers
239 views

Diastereoselective epoxidation of acyclic alkenes with VO(acac)2

I've been reading about diastereoselective epoxidation of acyclic alkenes with VO(acac)2. This is taken from Carey, Sundberg Advanced Organic Chemistry Part B: The OH and epoxide are syn. Then, while ...
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1answer
3k views

Dichromate in acidic medium

We were taught that $\ce{Cr_2O_7^{2-}}$ (dichromate) in $\ce{H_2SO_4}$ gives $\ce{CrO_3}$ $$\ce{Cr_2O_7^{2-} +H_2SO_4 -> CrO_3 + ...}$$ Link: wikipedia But we know that dichromate in acidic ...
5
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1answer
89 views

Why is hexafluoridonickelate(IV) diamagnetic?

As fluoride is a weak-field ligand, it should not pair up the electrons. So why is $\ce{[NiF6]^2-}$ diamagnetic?
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0answers
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Why some hydrates are coloured while other are not [duplicate]

I was studying about different vitriol and noticed that some hydrates are coloured while some are colourless even after having water in their crystals. For example; $\ce{FeSO4.7H2O}$ (iron sulfate ...
8
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1answer
4k views

Why isn't the orbital angular momentum also considered while calculating the magnetic moments 3d transition elements?

My textbook (Chapter: The d- and f- Block Elements) makes an interesting assertion, however, without any reason to back it up. Paramagnetism arises from the presence of unpaired electons, each such ...
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1answer
486 views

Balancing the equation

I've got a question: $$\ce{Cr2O7^2- -> Cr^3+}$$ This reaction takes place in a acidic medium - how many $\ce{H+}$ are required to balance the equation? How do I balance this reaction. Cr had ...
2
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2answers
193 views

What is the hybridisation in dimolybdenum?

Dimolybdenum's $\mathrm{4s}$ and $\mathrm{4p}$ orbitals are full. It is going to use its $\mathrm{4d}$ and $\mathrm{5s}$ orbitals to form a sextuple bond (2 $\sigma$, 2 $\pi$, 2 $\delta$). I am ...
15
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0answers
263 views

f-electrons in chemistry of heavy transition metals

In one lecture on recent MCR-X conference I was puzzled by a side-note "f-hole is critical to describe DoS of $\ce{IrO2}$ correctly." The context was DFT periodic plane-wave calculations with ...
3
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1answer
200 views

How do I determine the number and order of ligand orbitals?

I am trying to create interaction diagrams for transition metal species by reducing the representations for both $\sigma$ and $\pi$ ligand orbital sets and mixing them with the metal orbitals. The ...
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0answers
3k views

Why is the geometry of [Ni(CN)4)]2- square planar? Why is it colorless?

Why is the geometry of $\ce{[Ni(CN)4)]^{2-}}$ square planar given that it has a coordination number of 4? Shouldn't its geometry be tetrahedral as it would minimise the bond angle and hence repulsion?...
7
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1answer
15k views

How does aqua regia dissolve gold?

I recently learned that aqua regia can dissolve less reactive or noble metals like gold. Aqua regia is a mixture of $\ce{HCl}$ and $\ce{HNO3}$, but separately, neither of these acids dissolve gold. ...
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1answer
1k views

Anomalous oxidation states of Transition Metals

I have noted down the available positive oxidation states of the first row of transition elements (on the Periodic Table) from the respective Wikipedia articles of the elements. $\ce{Sc} - 3, ...