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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746 views

Is palladium on carbon acting as an oxidising or reducing agent?

In the conversion of piperidine to pyridine, palladium on carbon (Pd/C) is used. But it is reducing agent. Clear the confusion, please.
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Why does steric hindrance cause a d8 complex to have a tetrahedral geometry rather than a square planar geometry?

I'm currently working on a question based on two isomers of a nickel complex, where nickel exists in the oxidation state Ni(II) (i.e. has d-electron configuration d8). It has been deduced that the "...
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metallic bonding in transition metal sulfides

I searched on the internet but failed to find a clear solution for this question: Regarding transition metal sulfides like NiS or FeS, is there metallic bonding within their crystal structure? If ...
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152 views

Colour in vanadyl sulfate

What is the reason that vanadyl sulfate shows blue colour, even in its anhydrous form? If it's d-d transition, can you explain how it works in this compound?
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763 views

Jahn-Teller distortion of [Fe(H2O)6]2+

I am wondering whether Fe(II) hydrated to an octahedral complex would undergo a Jahn-Teller distortion. As far as I am aware, this distortion comes about because of asymmetry in filling orbitals, in ...
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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 ...
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Why does silver oxide form a coordination complex when treated with ammonia?

Part of the preparation of Tollens' reagent occurs according to the formula: $$\ce{Ag2O (s) + 4 NH3 + 2 NaNO3 + H2O → 2 [Ag(NH3)2]NO3 + 2 NaOH}$$ I wonder how exactly the oxygen gets "unstuck" from ...
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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 ...
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1answer
749 views

Color transition [closed]

We have to determine which method is true in order to find which color is absorbed and which one is transmitted? I have read in an example that $\ce{Cu^{2+}}$ absorbs red light but transmits blue....
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Platinum engagement ring as oxidation catalyst [closed]

I know platinum is used in the catalytic converter to oxidize pollutants. For a pollutant ($\ce{N_xO}$, $\ce{CO}$, etc., your choice), I'd like to get an order-of-magnitude rate of catalysis, ...
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Color of complexes d-d transition or electron exchange [closed]

I always have the problem of finding whether a complex has colour due d-d transition of electrons or if it is due to electron exchange. Is there a general way to tell whether a complex has d-d ...
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Why the ionization energy of Au is more than that of Cu?

As we go down the group from 3d to 5 d, size increases. Vanderwaal radius of Cu and Au is 140pm and 166pm respectively. Since Cu is smaller in size, ionization energy of Cu must be greater. Then ...
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HCl and chrome plated plastic [closed]

I was trying to use $\ce{HCl}$ (muriatic acid) to remove chrome plating from plastic chrome plated shower parts (shower head holder) in order to make chromium chloride. I understand that in chrome ...
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Why are heavy metal ions such as those of Hg and Cd toxic to animals?

Why are heavy metal ions such as those of Hg and Cd toxic to animals? While studying green chemistry I came to know about the Minamata disease caused by Hg and other disorders due to the accumulation ...
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Why is anhydrous CuSO4 White while hydrated CuSO4 is Blue? (even though both have one unpaired electron)

We all know that $\ce{CuSO4.5H2O}$ is blue and it turns to $\ce{CuSO4}$ on heating which is white. I also learnt about coordination complexes and d-d transitions and how transition metal compounds are ...
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Does Ni(H2O)6 have Oh symmetry or Th?

I optimized a geometry of $\ce{Ni(H2O)6}$ using quantum chemistry and got a molecule which is symmetrical for the $\ce{Ni-O}$ distances as shown here: In the literature it says that this complex has ...
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Why is ZnFe2O4 a normal spinel?

Considering that $\ce{Zn^2+}$ is $\mathrm{d}^{10}$, $\ce{Fe^3+}$ is $\mathrm{d^5}$, and $\ce{O^2-}$ is a weak field ligand, the CFSE values of both the normal and inverse spinel structures should be $...
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What does the crystal field splitting diagram for trigonal planar complexes look like?

For a trigonal planar complex (e.g. $\ce{[AgCl_3]^2-}$): According to this image (source): The $x^2 - y^2$ and $xy$ orbitals are on the same energy level. However, assuming that one of the $\ce{Cl}$ ...
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1answer
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Why does chromium(III) have the highest tendency to form complexes, comparatively, among Mn(III), Cr(III), V(III) and Ti(III)?

I was looking at some quick revision notes for d&f block elements and it had this random fact: Out of $\ce{Mn^3+}$, $\ce{Cr^3+}$, $\ce{V^3+}$, and $\ce{Ti^3+}$, chromium readily forms complexes. ...
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Why do the halides run in reverse orders in the spectrochemical series and the trans-effect series?

Spectrochemical series: $\ce{F^-}>\ce{Cl^-}>\ce{Br^-}>\ce{I^-}$ Trans-effect series: $\ce{I^-}>\ce{Br^-}>\ce{Cl^-}>\ce{F^-}$ This seems slightly odd to me because their relative ...
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Titanium in HF vs HCl

So we tried the reaction between Titanium metal with hydrochloric acid and hydrofluoric acid at a similar concentration. While boiling temperatures and constant heat over a long period of time are ...
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“Alternative” derivation of the spin-only formula

The spin-only formula $$\mu_\mathrm{so} = \mu_\mathrm{B} \sqrt{n(n+2)} = \mu_\mathrm{B}\cdot 2\sqrt{S(S+1)}$$ is usually a good first approximation to calculate the magnetic moment of transition ...
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Chromium +1 is unknown while Mn+2 is known?

Although both $\ce{Cr+}$ and $\ce{Mn^2+}$ both ions have $d^5$ configuration, still only $\ce{Mn^2+}$ is well-known while $\ce{Cr+}$ is not common. What is so special about Cr that it does not form $\...
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Why is ruthenium(III) intensely colored in water

I was preparing a solution of ruthenium(III) chloride (aqueous) when I added some (nearly black) $\ce{RuCl3 . H2O}$ to the water. I was surprised that a tiny amount could dye the water so well, I'd ...
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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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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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164 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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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. ...
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604 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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155 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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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 ...
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1answer
967 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. ...
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1answer
450 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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333 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?
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201 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{...
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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 ...
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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
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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 ...
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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 ...
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1answer
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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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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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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 ...
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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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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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709 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 ...
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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 ...
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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) ...
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41 views

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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122 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 ...
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1answer
744 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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