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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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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 $\...
4
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1answer
1k views

What's the configuration of chromium(III) in aqueous medium according to crystal field theory?

It has $\mathrm{3d^3}$ configuration, but how will we decide if they enter $\mathrm{t_{2g}}$ or $\mathrm{e_g}$ orbitals since we don't know which complex will form?
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1answer
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Why does iron have an abnormally high ionization energy?

Along a period the ionization energy should increase because the atomic number is increasing, but there is negligible increase in shielding. However, $\mathrm{IE}_\ce{Mn} < \mathrm{IE}_\ce{Fe} > ...
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1answer
851 views

How is solid titanium(II) oxide an electrical conductor?

Most salts in the solid state are electrical insulators, since the ions are not mobile (e.g. sodium chloride). However, solid titanium(II) oxide, $\ce{TiO (s)}$, is a conductor. How is this so?
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Iron-platinum refining

If I have an iron-platinum alloy, can I put this into a solution of $\ce{HCl}$ to dissolve the iron, leaving a $\ce{Pt}$ precipitate? I know that Fe dissolves in $\ce{HCl}$ to form $\ce{FeCl2}$ and $\...
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203 views

Transition Metals that react with Vanillin and their Complexes [closed]

My question is simply whether anyone knows what are the transition metals that the phenol group of the vanillin molecule could react with, and thereby produce discolorations. This question is ...
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1answer
91 views

How to reconcile conflict between assumed oxidation state and the most stable multiplicity from electronic structure calculations?

Consider either of the small, neutral molecules containing two Zn atoms below. If I were to determine the oxidation state of Zn from this molecule, I would formally assume each Zn to be Zn(I) in order ...
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1answer
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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 $\mathrm{d^6}$...
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0answers
107 views

Toxicity of vanadium in pottery

I mix and develop glaze recipes for midfire stoneware (fired to 1220°C). The colorants in pottery are mostly iron, copper, cobalt, tin, titanium, chrome, and a few other transition metals. Many of ...
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2answers
7k views

Regular decrease in the atomic radius of 3d series

While comparing atomic radius, two factors are important: A. Decrease in size due to increase in effective nuclear charge B. Increase in size due to increase in shielding effect I was surprised to ...
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379 views

What is the activation energy of iron rust?

Iron rusts to Geothite (FeO(OH)). What is the activation energy for this reaction? Where can I find this information?
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Why is the tetraamminecopper(II) ion square planar?

The tetraamminecopper(II) ion is square planar in shape. But why? How can I rationalise this? Can I rationalise this without the concept of hybridization? And even if I take hybridization into ...
5
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3answers
525 views

Can one turn a nickel blue?

I've heard of artificial coin toning, but haven't been able to find a recipe for creating a blue (or blue-ish) nickel coin. While not a metallurgist, I work with one. She tried nitric acid, which ...
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1answer
106 views

Metals Vapor Pressure [duplicate]

I know metals like copper, silver and gold for example have vapor pressures at high temperature but do their vapor pressures still exist at standard temperatures (290 kelvin) and pressures (100 ...
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97 views

Relative orbital energies of Mn and Ni

In this MO diagram, why are the atomic Mn $3d$ orbitals higher in energy than the Ni $3d$ orbitals?
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311 views

Calculation of Bond/Angle/Dihedral force constant

I am a big fan of Mopac (Though I have a very little knowledge about the tool). I have some queries regarding some calculations in Mopac2016: Problem: How to calculate Bond or Angle or Dihedral ...
45
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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 ...
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1answer
185 views

What is the systematic name of ammonium bisoxalato cuprate (II)? [closed]

What is the systematic name of ammonium bisoxalato cuprate(II)? I already tried $\ce{(NH4)2[Cu(C2O4)2]^{2+}}$ but i am uncertain if that answer is correct.
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1answer
7k views

Reaction of iron(III) oxide with nitric acid [closed]

I'm currently working in a project in which I have to convert the iron oxides present in iron ore slime into ferric nitrate. Iron ore slime is which has the particle size of below $\pu{0.15 mm}$ is ...
7
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1answer
180 views

Different chemoselectivity of transition metals in catalytic hydrogenation

I am quoting my Clayden et al 2nd edition: Some catalysts are particularly selective towards certain classes of compound – for example, Pt, Rh and Ru will selectively hydrogenate aromatic ...
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1answer
2k views

Do Ligands electrons fill the d-orbitals of the metal ion? [duplicate]

We know that ligands make coordination bonds with d-orbitals of transition metals forming complexes. My question is, if that happened, all d-orbitals will be filled and no electron transition could ...
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1answer
191 views

Is the surface of the planet Mercury made of copper minerals?

I have been looking at photographs of the planet Mercury, and I notices that in most of the pictures I have seen, the rocks on the surface seem to be covered in blue in green. From this, is it correct ...
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2answers
576 views

Number of unpaired electron and total spin angular moment

IIT-JEE advanced 2013 has a question: Give the correct order of the complex ions given below according to their spin-only magnetic moment: A. $\ce{[FeF6]^{3-}}$ B. $\ce{[V(H2O)6]^{2+}}$ C. $\...
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1answer
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Is there an explanation to the atomisation energy trend of transition metals?

I am familiar with the double hump trend for atomisation of transition metals, and I can explain the unusually low atomisation of $\ce{Mn}$ with the exchange principle, specifically that in the solid ...
5
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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 ...
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0answers
244 views

Are lustre and conductivity directly related?

In a question that I had asked before, Is chromium the shiniest metal?, I received the answer that silver was, in fact the most lustrous metal for visible wavelengths. At the same time, silver is also ...
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1answer
675 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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1answer
492 views

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 $d^8$). It has been deduced that the "...
2
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0answers
257 views

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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1answer
144 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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1answer
710 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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2answers
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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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3answers
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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 ...
22
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1answer
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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 ...
2
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1answer
666 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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0answers
61 views

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, ...
3
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0answers
593 views

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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1answer
2k views

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 ...
2
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0answers
98 views

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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0answers
69 views

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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2answers
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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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0answers
373 views

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 ...
7
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1answer
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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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2answers
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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. ...
5
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2answers
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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 ...
4
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1answer
2k views

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 ...
6
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0answers
529 views

“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 ...
3
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1answer
66 views

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 $\...
4
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1answer
934 views

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 ...