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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22
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1answer
16k 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 ...
5
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0answers
166 views

How to rationalise the trend in the covalent radii of the transition metals?

Why do the covalent radii of transition series decrease at the start rapidly, then become almost constant and at the end of series begin to increase from left to right in periodic table?
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1answer
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Why is Cr²⁺ is a good reducing agent but Mn³⁺ is a good oxidising agent?

The question is the same as the title states. In my text book,the following is written $\ce{Cr^{2+}}$ gets converted to $\ce{Cr^{3+}}$ as the +3 oxidation state hase half filled $\mathrm{t_2g}$ ...
6
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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?
6
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4answers
22k views

Why is zinc more reactive than copper?

In terms of electronegativity, from what I understand electronegativity increases going across the period, so surely this should mean that zinc less readily loses its outer shell electrons than copper?...
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2answers
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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 ...
-4
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1answer
508 views

Is it possible to form a divalent transition metal ion that has neither s- nor p-shell valence electrons? [closed]

Can a transition metal ion with a charge of 2+ form without valence shell s and p electrons?
2
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1answer
5k views

NO linear vs bent - valence electron

I'd like to count the total valence electron of following neutral complex in the ionic counting (=donor-pair): $\ce{Cl-}$ : 6e $\ce{CH3-}$: 2e $\ce{PPh3}$: 2e gives 10e from these three ligands 1....
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1answer
552 views

Do Palladium(II) Chloride and Palladium (III) Chloride follow 18-Electron rule or octet rule? How to determine this?

Does $\ce{PdCl2}$ follow 18-Electron rule or octet rule? How should we determine this? http://pubchem.ncbi.nlm.nih.gov/compound/24290#section=Top http://pubchem.ncbi.nlm.nih.gov/compounds/3494742#...
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1answer
6k views

Does iron(III) sulfate react with copper?

As my understanding, there should be an oxidation-reduction reaction: $$ \ce{2 Fe^3+ + Cu → 2Fe^2+ + Cu^2+} $$ However, I always see the process using $\ce{FeCl3}$ to etch copper, but I never ...
2
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1answer
3k views

Magnetic moments of tetrahedral Cobalt (II) and (III) complexes

From the spin-only formula we can predict that for tetrahedral cobalt (II) complexes $$m_{eff} = 3.87 \mu_B $$ This ignores orbital angular momentum effects, which result in higher magnetic moments ...
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3answers
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How can I derive the preferred oxidation states of a transition metal from its electronic configuration?

For example $\ce{Fe}\ (Z=26)$ Short formula: $\mathrm{1s^2\ 2s^2p^6\ 3s^2p^6d^6\ 4s^2}$. If we make the electronic formula we get 4 single electrons ($s=1/2$), which means that the valence in normal ...
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1answer
114 views

Is a metal hydroxide fully or partly oxidised in insufficient base?

Firstly, my question only applies to transition metal compounds with more than one hydroxide group, otherwise it would be more obvious. The reason I'm asking is in an effort to oxidise some nickel ...
1
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1answer
25k views

Why does potassium permanganate turn colourless when reacted with sulfur dioxide?

I learnt at school that when sulfur dioxide gas, $\ce{SO2}$, is combined with potassium permanganate, $\ce{KMnO4}$, the purple solution will become colourless. What happens in the solution to cause ...
3
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1answer
296 views

Metal-Ligand-Complex and bond directions: What defines coordinate system of the complex ion? [duplicate]

I have a question concerning metal ligand complexes. In every chemistry text book I have read which treats metal ligand complexes, following situation is discussed: When 6 ligands (in octahedral ...
6
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1answer
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Dissociation rates: trans-effect rule in square planar complexes

In lecture, the trans-effect was described. A ligand $L^t$ with a higher trans-effect as $L$ (cis to $L^t$) leads to a faster dissociation of ligand $L^d$ (trans to $L^t$). I would expect that the ...
2
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4answers
2k views

Colour of Nickel thiocyanate

What is the colour of $\ce{C2N2NiS2}$ (Nickel thiocyanate)? In most of the web sites it only molecular weight,formula and other specifications but its colour is missing every where.
4
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1answer
642 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 ...
38
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1answer
960 views

Relativistic effect: d-electrons in metallorganic complexes

With higher period the d-electrons of the metal are less strong bonded and therefore oxidative addition is easier for $\ce{Ir(I)}$ than for $\ce{Rh(I)}$ and much easier than for $\ce{Co(I)}$. For ...
7
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2answers
51k views

Why does Co2+ have 7 electrons in the 3d orbital, and not 5 like Mn?

I'm taking general chemistry 2 this half of the summer. We are currently going over coordination complexes, ligands and transition metal ions. In particular, this question is in regards to the ligand ...
4
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1answer
14k views

What makes a ligand stronger than another?

A ligand is a neutral molecule or negative ion with at least one lone pair of electrons which forms a dative covalent bond with a complex ion that has a vacant, energetically accessible orbital. It ...
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1answer
492 views

Explanation for increase in the number of oxidation states for transition elements from Sc to Mn of the 4th period

From Sc, to Mn, the number of oxidation states increases from one (Sc) to seven (Mn). The explanation for this is because the unpaired 3d electrons can be lost along with the 4s electrons during ...
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2answers
3k views

Transition metal order of filling electron

There is a specific order for filling electron for transition metals, but I don't know if it applies to other elements too? Some thing to take note of in this picture is the order of 3d and 4s. My ...
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1answer
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Valence Shell for Transition Metals

In transition metals, is the shell with the highest energy considered the valence shell? For example, in copper the electronic configuration is ${[Ar]\text{ } 3d^{10}\text{ } 4s^{1}}$. However, in ...
2
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1answer
230 views

Why is Technetium unstable?

Technetium is probably the most awkward element of the periodic table for me. It seems to me that Technetium is an exception, in the sense that it doesn't have any stable isotopes, despite having a ...
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1answer
287 views

How is square planar geometry possible in metal complexes?

I came across this statement and I don't understand what it meant by it: "Square planar geometry is favoured by ligands that can form pi bonds by accepting electrons from metal atoms or ions." How ...
12
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1answer
544 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 ...
3
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2answers
6k views

Stability of transition metals in aqueous solution

Which is more stable in aqueous solution: $\ce{Cr^3+}$ or $\ce{Mn^3+}$? Why? My approach: $\ce{Cr^{3+}}$ should be more stable as the $\ce{3d}$ electrons will enter the $\mathrm{t_{2g}}$ orbitals. ...
2
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3answers
346 views

Heating CrCl3(bpy)3 — isomerism and ligand exchange

$\ce{CrCl3(bpy)3}$ (A) when heated forms (B) which has the formula $\ce{CrCl3(bpy)2}$ and has one free $\ce{Cl-}$ per mole of (B). B can react with ethylene diamine ($\ce{en}$) to form (C) which has ...
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1answer
4k views

Spectrochemical Series - Sigma Donor Capability

I fully understand and recognise the manner and which the series works. I cannot find any references for the change in sigma donor capability moving up the series. For example, comparing $\ce{Cl-}$ ...
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1answer
837 views

Crystal Field Theory diagram

I need to draw a simple crystal field splitting diagram and identify the lowest-energy spin-allowed ligand field band in the electronic absorption spectrum for [MnCl6]2-. I know the basics of the ...
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1answer
696 views

Different coloured chromium salts

Evaporating cold aqueous chromium(III) chloride produces violet crystals. However when hot aqueous chromium(III) chloride crystallizes, green crystals result. Could someone please explain the ...
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2answers
14k views

What reaction takes place when potassium iodide is added to a tetraammine copper(II) complex?

I am given a blue solid W and it contains a tetraamine copper(II) complex and a $\ce{SO_4^{2-}}$. I added dilute sulfuric acid until the solution is pale blue; then added potassium iodide solution. A ...
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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?
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1answer
5k views

Why Gold and Silver react minimally with atmosphere?

Gold and Silver atoms interact with one another to form reasonably strong metallic bonds, but surprisingly they have almost no chemical interaction with atmosphere. How can we explain it based on the ...
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1answer
4k views

Why does $\text{Cr}^{3+}$ not have the same electron configuration as $\text{Sc}$?

To be explicit, $\text{Cr}^{3+}$ and $\text{Sc}$ have the same number of electrons, the only difference is the nuclear charge. This is not an isolated anomaly, it seems: the book I'm using claim ...
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1answer
3k views

Extraction of nickel from its ores [closed]

How is nickel mined and extracted from its ores? What are the appropriate word and chemical equations for this process?
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2answers
1k views

Problems with precipitation of transition metal solution

I am trying to make a solution of "trace elements"--primarily transition metals-- for use in biological media; bacteria require elements like Cobalt, Molybdenum, iron, etc. in trace amounts. I am not ...
12
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2answers
8k 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 ...
3
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2answers
280 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 ...
5
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1answer
973 views

Variable oxidation state of transition metal ions

Transition metals can form stable ions with different oxidation states. But I am confused why doesn't only the most stable state exist. Let me clarify my question more: $$\ce{Ti^{2+} -> Ti^{3+} + ...
2
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1answer
802 views

Ligand exchange reactions… are they one way or reversible?

Are ligand exchange reactions one-way reactions or reversible? I know this is a very silly question but its not said outright in any place... For example, in my high school chemistry book, these two ...
13
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2answers
3k 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 ...
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 ...
194
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1answer
40k 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, ...
2
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1answer
147 views

Do the compounds NaₓIrO₂ and NaOsO₂ exist?

Based on some physics background, I want to know whether have scientists synthesized these two materials: $\ce{Na_{$x$}IrO2}$ and $\ce{NaOsO2}$ in the lab, if so, what properties do they have? I ...
10
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3answers
16k 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 ...
4
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4answers
6k views

Why is zinc deposited on copper when boiling an aqueous zinc sulfate solution?

I did an experiment where I dissolved 30 grams of zinc sulfate in water and boiled it with strips of solid zinc metal and strips of copper metal and a layer of zinc was deposited on the copper. I ...
2
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0answers
728 views

Bond Lengths in FCC, BCC and HCP Structures

I was wondering what the crystal structures of FCC, BCC and HCP actually look like, and where atoms are placed in their configuration? Specifically I'm looking at elemental nickel, iron and cobalt ...
3
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1answer
10k views

Calculating percentages of microstructures in equilibrium phase diagrams (engineering)

So I have an equilibrium phase diagram of steel and I am asked to 'Calculate the proportion of pearlite in the microstructure of 0.4 wt% C steel just below the eutectoid temperature (727 °C).' I have ...

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