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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Why does density decrease across the period 4 and 5 transition metals?

I know that density decreases across period 4 because the last two elements are liquids and gases which means that their densities are less but why are the densities increasing and then decreasing ...
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Separating nickel coin into copper and nickel components

I'm trying to create a high school level lab in which we separate the metals in an alloy. The objective is to understand and apply standard reduction potentials, and also to do some extra redox ...
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Why is tetraamminecopper(II) a square planar and not a tetrahedral species?

In $\ce{[Cu(NH3)4]^2+}$, the $\ce{Cu^2+}$ ion has 9 electrons in the $\mathrm{3d}$ orbital with only one unpaired electron. How is it a square planar geometry? Where is that unpaired electron going?
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Why do transition metals tend to form positive ions instead of negative ions?

I have learnt that elements on the left-hand side of the periodic table such as sodium and magnesium prefer to lose electrons to form a cation because this requires less energy to obtain a stable ...
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Why is it that the least reactive metals are the best electrical conductors?

Silver, Gold and Platinum are amongst the best conductors of electricity, but also the amongst the most unreactive. Since electrical conductivity depends on the number of delocalized electrons (along ...
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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 ...
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Why is Cr(2+) a stronger reducing agent than Fe(2+) in water?

According to me, $\ce{Fe^{2+}}$ should be a better reducing agent because $\ce{Fe^2+}$ - after being oxidized - will attain a stable $\ce{d^5}$ configuration, whereas $\ce{Cr^2+}$ will attain a $\ce{d^...
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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 ...
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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 ...
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Palladium Nanocube

What is the relative permittivity and relative permeability of a palladium nanocube? If I change the size of this $\ce{Pd}$ nanocube, will these values be changed or remain the same?
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Pb-based pigments and rhodizonate salts

In a previous question, I learned that we can detect lead with sodium / potassium rhodizonate, giving a nice purple color when reacting with pure (elemental?) lead. But in the paint, lead is ...
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Trans effect on square planar complex [closed]

We've learnt about the trans effect but I have a question regarding how this plays a role with water in the equation. trans-effect: $$\ce{H2O < NH3 < Cl-}$$ Based on this, given cis-$\ce{[Pt(...
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Why are Group 11 elements unreactive?

Group 11 metals namely $\ce{Cu, Ag, Au}$ are known for their low reactivities. They are thus rightly called coinage metals and have been historically used to make currency owing to this very property ...
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Are all complexes with a polydentate ligand examples of chelation?

I'm getting a little confused about the definition of chelation and its implications (I should probably point out I'm only an A2 Chemistry student). The IUPAC defines chelation as the following: ...
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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 $\ce{Cr^6+}$ ...
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Why is mercury liquid? [duplicate]

Why is mercury the only metal that is liquid at room temperature? Note: I am a high school student and would appreciate an answer, if possible, suited for my level of understanding. Thank you.
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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_{\...
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How many electrons are in the d orbitals of NiCl2·6H2O?

On Wikipedia, it says that $\ce{NiCl2·6H2O}$ consists of separated trans-$\ce{[NiCl2(H2O)4]}$ molecules linked more weakly to adjacent water molecules. Only four of the six water molecules in ...
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648 views

Why do complex ions not emit light from de-excitations of electrons?

I understand that complex ions are coloured due to d-orbital splitting which results in electrons being able to absorb wavelengths of visible light and become excited to the higher energy state ...
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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)...
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Molecular orbital diagram of a complex including an oxido ligand

With highly oxidized metal centers, we expect that the hydroxido ligand's proton becomes acidic and will be lost to the surrounding media, creating an oxido ligand. The oxo ligand is a $\pi$ basic ...
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Is hydrolytic polymerisation the mechanism by which the precipitate forms from the neutral complex?

From basic coordination chemistry and acid-base equilibria we understand that a metal hexa-aqua ion can be deprotonated until it's positive charge is balanced by the negative charge of the hydroxides ...
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Why are multiple oxidation states useful for a catalyst?

Transition elements are good catalysts because they have multiple oxidation states?Why multiple oxidation states matter?
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Why is there a difference in the colours of K₂Cr₂O₇ and K₂CrO₄?

In both the compounds the oxidation state of Chromium is +6 so why is there a difference in the colours of their aqueous solutions. $\ce{K2Cr2O7}$ is red-yellow and $\ce{K2CrO4}$ is bright yellow I ...
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Protein purification with Cobalt

Cobalt exhibits a more specific interaction with histidine tags, resulting in less nonspecific interaction than nickel. For this reason, cobalt is the preferred divalent cation for purifying His-...
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Predicting orbital angular momentum effects on magnetic moments

For metal complexes with $A_{2}$ or $E$ ground state terms there is angular momentum contribution to the magnetic moment which is generally positive for more than half-filled subshells and negative ...
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Manganese(VII) oxidation state

A transition element is one which forms one or more stable ions which have partially filled d-orbitals. Manganese (Mn) could have an oxidation state of 7+, which means that it will lose all of the $\...
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What is the electronic configuration of Fe(II) ion?

The electronic configuration of Fe is $\ce{[Ar] 3d^6 4s^2}$. So after removing two electrons the configuration becomes: $\ce{[Ar] 3d^6}$ But why can't the electrons rearrange themselves to give a ...
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Does sodium form complexes like transition metal ions?

I realise that there is a similar question here Difference between sodium ion and a transition metal ion dissolving in water? and it seems to answer my question, however I was reading about how ...
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1answer
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How can transition metals form so many bonds with ligands? [duplicate]

For instance, copper can form $\ce{[Cu(H2O)6]^2+}$ so it accepts 6 electron pairs from $\ce{H2O}$ molecules to form dative covalent bonds. However it has one electron in the 4s subshell and 10 in the ...
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Why are transition metal hydroxides insoluble?

From what I understand, adding $\ce{NaOH}$ to a solution containing transition metal ions gives transition metal hydroxide precipitates. Why is $\ce{NaOH}$ soluble but transition metal hydroxides ...
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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 ...
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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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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 $\mathrm{t_2g}$ ...
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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?
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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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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 ...
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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?
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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
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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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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 ...
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1answer
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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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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
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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 ...
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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 ...
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1answer
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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 ...
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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 ...
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4answers
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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.
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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 ...
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1answer
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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 ...