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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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60
votes
4answers
28k views

Why do elements in columns 6 and 11 assume 'abnormal' electron configurations?

When I look around for why copper and chromium only have one electron in their outermost s orbital and 5/10 in their outermost d orbital, I'm bombarded with the fact that they are more stable with a ...
20
votes
1answer
6k views

How can the intense color of potassium permanganate be explained with molecular orbital theory?

In the permanganate ion, manganese is in the $+7$ oxidation state, therefore it is a $\ce{d^0}$ ion. $\ce{d^0}$ and $\ce{d^1^0}$ ions don't absorb visible spectrum radiation because there are no ...
45
votes
3answers
3k views

Why is it wrong to use the concept of hybridization for transition metal complexes?

I have asked a lot of questions on coordination chemistry here before and I have gone through a lot others here as well. Students, including me, attempt to answer those questions using the concept of ...
55
votes
4answers
40k views

How can one explain niobium’s weird electronic configuration?

As cited in an answer to this question, the ground state electronic configuration of niobium is: $\ce{Nb: [Kr] 5s^1 4d^4}$ Why is that so? What factors stabilize this configuration, compared to ...
22
votes
1answer
28k views

Why is [PdCl4]2- square planar whereas [NiCl4]2- is tetrahedral?

The molecule $\ce{[PdCl4]^2-}$ is diamagnetic, which indicates a square planar geometry as all eight d electrons are paired in the lower-energy orbitals. However, $\ce{[NiCl4]^2-}$ is also $\mathrm{d^...
21
votes
3answers
29k views

Why are some salt solutions coloured?

I notice that salt solutions of $\ce{NaCl}$ and $\ce{KCl}$ are colourless while those of $\ce{CuSO4}$ and $\ce{FeSO4}$ are coloured. I got as far as figuring that it has to do with the transition ...
22
votes
1answer
1k views

While filling electrons, we follow Aufbau principle, but not while removing them. Why is this so?

I recently came across a question Why is the vanadium(3+) ion paramagnetic?, where the asker is wondering how $\ce{V^{3+}}$ is paramagnetic (he used Aufbau in reverse to remove the electrons), while ...
10
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2answers
23k views

Why do 3d orbitals have lesser energy than 4s orbitals in transition metals? [duplicate]

This is quoted from Jim Clark's Chemguide For reasons which are too complicated to go into at this level, once you get to scandium, the energy of the 3d orbitals becomes slightly less than that of ...
7
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1answer
3k views

Cr(II) and Mn(III) - their oxidizing and reducing properties?

My textbook states that $\ce{Cr^2+}$ is a reducing agent while $\ce{Mn^3+}$ is an oxidizing agent in spite of both having $\ce{d^4}$ configuration. The explanation states that when $\ce{Cr^2+}$ gets ...
22
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2answers
51k views

Melting and boiling points of transition elements

The melting and boiling points of transition elements increases from scandium ($1530~\mathrm{^\circ C}$) to vanadium ($1917~\mathrm{^\circ C}$). They increase because as we go across the group, we ...
19
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4answers
5k views

Why is ligand substitution only partial with copper(II) ions and ammonia?

When studying ligand substitution (at UK year 13 level), the following example has been given: \begin{align} \ce{[Cu(H2O)_6]^2+ + 2NH3 &<=> [Cu(OH)_2(H2O)_6] + 2NH4^+}\\ \ce{[Cu(OH)_2(H2O)...
9
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2answers
3k views

Why do copper (II) complexes contain so many valence electrons?

Consider tetraaminecopper (II) ion. $\ce{[Cu(NH3)4]^2+}$ or $\ce{[Cu(NH3)4(H2O)2]^2+}$. The copper(II) ion has the electron configuration $\mathrm{[Ar]\ 3d^9}$. How do the 4 electron pairs from the ...
16
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2answers
830 views

Why is WF6 stable whereas CrF6 is unknown?

$\ce{F-}$ is a hard base since it is small and relatively polarizable. Both $\ce{Cr^6+}$ and $\ce{W^6+}$ are hard acids, but shouldn't $\ce{CrF6}$ be favored since it would be a smaller hard acid?
15
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1answer
2k views

What is the nature of the Fe–O2 binding in oxymyoglobin and oxyhemoglobin?

Deoxymyoglobin ($\ce{Mb}$) is known to have iron in the +2 oxidation state; I believe this was deduced from its magnetic moment, which corresponds to four unpaired electrons in high-spin $\mathrm{d^6}$...
37
votes
1answer
61k views

Why is the vanadium(3+) ion paramagnetic?

I know that the electron configuration of vanadium is $[\ce{Ar}]\mathrm{4s^2 3d^3}$. None of the electrons in the 3d subshell are paired. Once it loses these three electrons, shouldn't the remainder ...
15
votes
2answers
3k views

Why are noble metals more electronegative then most metals?

I was researching about electronegativity when I looked up what a graph of electronegativity within the periodic table is. And, this appeared. I scanned it, matching up everything I knew about the ...
12
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1answer
4k views

Splitting of $d$ orbitals when ligands approach central metal ion

In my high school chemistry book, it is written that when ligands approach the central metal ion (transition metal ion) to form dative bonds, the $3d$ orbitals split into two: two which are in higher ...
12
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2answers
7k views

Is pyrite (FeS₂) an ionic or a covalent compound?

I have searched all over the web and found a lot of diverse explanations, but none of them are concluding exactly whether $\ce{FeS2}$ (solid - pyrite) is a covalent or an ionic compound. From ...
5
votes
1answer
365 views

Formation of MnO2 vs [Mn(H2O)6]4+ in aqueous solution

I am looking for reasons why $\ce{Mn(IV)}$ wouldn't be stable as a hydrate. I know that from standard reduction potentials it exists as a ppt of $\ce{MnO2}$, but what is stopping it from being a ...
164
votes
1answer
36k views

Why can we smell copper?

If I can smell an object, it means that molecules of it are getting separated from it, so they can reach my nose. As far as I know, metals don't sublimate, especially not in room temperature. However, ...
29
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4answers
216k views

Why do transition elements make colored compounds?

Why do transition metals element make colored compounds both in solid form and in solution? Is it related to their electrons?
22
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1answer
15k views

Can metals have a net negative charge

Normal metals like sodium or Calcium have a positive charge as $\ce{Na}^+$ or $\ce{Ca}^{2+}$. Transition metals have a loot of variable oxidation states. Yesterday I read about Iridium in Wikipedia ...
8
votes
1answer
17k views

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 ...
8
votes
2answers
1k views

In an octahedral complex, what happens to the electrons donated by the ligand?

I am trying to understand how complexes are coloured. After some reading, I found out this was due to the d-d splitting induced by the coordinate bonds of ligands to the central metal ion. The ...
6
votes
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 ...
17
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2answers
79k views

Why are there peaks in electronegativities in d-block elements?

Looking at the Pauling electronegativities in the Periodic Table (below, from ChemWiki): Asides from the overall trend of increasing electronegativity across and up the Periodic Table (towards ...
13
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2answers
2k views

What happens to electrons in metal complexes after excitation by visible light?

My book writes: When white light shines through a solution of a complex ion of a transition metal, photons of a particular frequency are absorbed and their energy promotes an electron from lower ...
8
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2answers
1k views

Why is Ni[(PPh₃)₂Cl₂] tetrahedral?

Since PPh₃ is strong field ligand and, the famous Wilkinson's catalyst, which also possess this ligand is square planar, then what makes the above complex tetrahedral?
7
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3answers
12k views

What is the origin of the colour of azo dyes?

Is it the same reason as to why transition metal complexes have colour?
4
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2answers
4k views

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 ...
3
votes
1answer
3k views

Why is hexafluoridocobaltate(III) the only common high-spin cobalt(III) complex?

Almost all $\ce{Co^3+} (\mathrm{d^6})$ complexes are low spin, including $\ce{[Co(H2O)6]^3+, [Co(ox)3]^3–, [Co(NH3)6]^3+}$ and $\ce{[Co(CN)6]^3–}$. The only common high-spin cobalt(III) complex is $\...
3
votes
1answer
3k 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 ...
3
votes
1answer
7k views

What is the reason for the anomalous electronic configuration of palladium? [duplicate]

The p block elements generally have the general valence shell configuration as $$n\mathrm{p}^{1-6}\,n\mathrm{s}^{1-2}.$$ Expected electronic configuration for palladium is $$\ce{^46Pd} = \mathrm{1s^2\,...
12
votes
1answer
528 views

What is the Structure of FeSO₄ • NO?

What is the structure of $\ce{FeSO4 \cdot NO}$ that is formed when $\ce{NO}$ is passed through ferrous sulfate solution? If it is a brown ring complex then why does the complex sphere break upon ...
4
votes
1answer
580 views

Is the colour of leaves due to d-d transitions in chlorophyll?

While reading a chapter on transition metals, I came to know that d-Block elements have colour compounds due to d-d transitions. A question came to my mind as to whether there is any d-d kind of ...
3
votes
2answers
278 views

Can we goldify metals?

I've read in some book that one of the old chemists was able to transform cheap metals into gold. I know that gold is an element (Au) so we can't transform a metal into Au. But as I read further it ...
2
votes
1answer
535 views

In crystal field theory, why do all the metal electrons enter the d orbitals and not the s orbital?

Suppose we have the complex $\ce{[Fe(H2O)6]}$. Iron has 26 electrons, and its electronic configuration is therefore $[\ce{Ar}]\,\mathrm{4s^2 3d^6}$, but in crystal-field theory, we say that the $\...
1
vote
0answers
106 views

Why tungsten does not have stable configuration? [duplicate]

Whenever there are 4 unpaired electrons in d-orbital, elements try to attain stable electronic configuration. For example copper. Electronic configuration of copper should be [Ar]3d4 4s2, but it ...
0
votes
1answer
206 views

How many d-eletrons are in the outer shell of following compounds:

How many d-electrons are in the outer shell of the metals in following compounds: $\ce{ZnS}$ and $\ce{NiS}$ So sulphur does not has any $\ce{d}$ electrons and $\ce{Zn}$ has $10\ce{d}$ electrons. ...
-1
votes
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?
8
votes
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 ...
10
votes
3answers
15k views

Hybridisation of Mn in potassium permanganate

I'm clear with the concepts of crystal field theory. But I can't figure out the exact reason why the hybridisation of manganese in potassium permanganate ($\ce{KMnO4}$) is $\mathrm{d^3s}$. Can anyone ...
10
votes
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 ...
7
votes
1answer
3k views

Why are compounds of V5+ and Cr6+ colored? [duplicate]

As far as my knowledge goes, transition metal complex ions show a color due to a transfer of electrons between the levels of split $\mathrm d$-orbitals. In the case of $\ce{V^5+}$ and $\ce{Cr^6+}$ ...
6
votes
1answer
2k views

Why is enthalpy of atomization of Mn exceptionally low?

Transition elements usually have high values, especially so for greater number of unpaired electrons. Why the exception here?
16
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2answers
26k views

In Crystal Field Theory what does Δo=10Dq mean?

While studying the Crystal Field Theory I was told $\mathrm{Dq}$ is a unit, related to the unit $\Delta_{\mathrm{O}}$ by the relation $\Delta_{\mathrm{O}} = 10\ \mathrm{Dq}$. But aren't $\Delta_{\...
11
votes
4answers
4k views

Are complex ions thermochromic?

Does raising the temperature of a complex ion (formed from a transition metal ion and ligand(s)) affect its color? For example, if the temperature of $\ce{[Cr(H2O)6]^3+}$ is raised, will its color ...
8
votes
1answer
945 views

Sodium permanganate from manganese dioxide and sodium hypochlorite

This page states that sodium permanganate can be formed by the reaction of manganese dioxide with sodium hypochlorite and sodium hydroxide: $$\ce{2 MnO2 + 3 NaClO + 2 NaOH -> 2 NaMnO4 + 3 NaCl + ...
8
votes
0answers
782 views

What is the chemistry behind black colour of platinum black? [duplicate]

Platinum is a silvery white metal and is highly unreactive then why it's powdered form "platinum black" is platinum metal but is black in colour. why would a metal such as platinum become black as a ...
8
votes
0answers
16k views

Mechanism for an Étard reaction (chromium complex)

In the following reaction, a chromium complex is formed during the Étard reaction: I have the following questions: How is this complex formed? How does its hydrolysis take place? (What's the ...