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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6
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0answers
101 views
+50

How to compare magnetic moment of chromium(III) and cobalt(II) ions?

Is there any way of comparing magnetic moment of $\ce{Co^2+}$ and $\ce{Cr^3+}$ by just going through their electronic configuration?Or is it just experimental data?
6
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1answer
147 views

Why is it advised to use neutral ferric chloride solution while performing confirmatory test for acetate ions? [duplicate]

The reaction of $\ce{FeCl3}$ with $\ce{CH3COO-}$ is $$\ce{3Fe^{+3} +6CH3COO- +H2O<=> [Fe3(OH)2(CH3COO)6]^{+} +2H^{+}}$$ Recently I read that a solution of $\ce{FeCl3}$ hydrolyses very quickly to ...
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36 views

Is tetrachloridocuprate(II) formed when dilute hydrochloric acid is added to a solution containing tetraamminecopper(II)?

As observed in the lab, when concentrated $\ce{HCl}$ is added to a solution of deep blue $\ce{[Cu(NH3)4]^2+}$ a green color appears indicating the partial formation of the yellow colored $\ce{[CuCl4]^...
5
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0answers
82 views

Explanation of the trans-effect (thermodynamic and kinetic) for octahedral transition metal complexes

The thermodynamic trans effect refers to the ground state weakening of the metal-ligand bond in a complex by a ligand trans to it. The kinetic trans effect is the lablisation of a ligand in a complex ...
2
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1answer
61 views

Can aqua regia/royal water dissolve lead? [duplicate]

As known aqua regia can't dissolve $\ce{Ag}$ because formation of $\ce{AgCl}$ precipitate. Similarly will aqua regia precipitate $\ce{Pb}$ as $\ce{PbCl2}$? OR It is not possible to observe this ...
-4
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1answer
38 views

Noble gas configuration and valence shell electrons [duplicate]

I know that the maximum number of electrons within a shell is equal to 2n^2. I would think that the noble gases would reflect this but that isn’t always the case n = 1 2(1^2) = 2, this is the atomic ...
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0answers
22 views

Why are transition metal so good catalysts? [duplicate]

Transition metals (TMs) are used as catalysts in a wide variety of chemical reactions, both industrially and in living organisms. What properties do transition metals have that main group elements do ...
2
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2answers
225 views

Why is osmium(VIII) oxide so toxic?

Osmium(VIII) oxide or osmium tetroxide is a volatile chemical compound with the formula of $\ce{OsO4}$. It is highly toxic for supposedly irritating mucous membranes, but I'm not too sure if it is ...
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3answers
89 views

How does copper oxidise alcohols?

Consider for example ethanol being heated in the presence of copper at 300 °C. How does it give ethanal as a product? Copper being in its elemental state (oxidation state 0). Since negative oxidation ...
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1answer
56 views

Why does Co(I) have a 3d8 configuration?

Why is the electron configuration of $\ce{Co^+}$ $[\ce{Ar}](\mathrm{3d})^8$? Since neutral $\ce{Co}$ itself has a $[\ce{Ar}](\mathrm{4s})^2(\mathrm{3d})^7$ configuration, wouldn't the ionised electron ...
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1answer
192 views

Finding the valency of transition metals in coordination complexes

I understand how to find the valency of atoms in small organic compounds. For instance, for CH4, the valency of carbon is 4, while the valency of each hydrogen is 1. But for a coordination complex, ...
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0answers
26 views

Why can zinc porphyrins assume 5 coordinate geometries?

It has been reported that 5-coordinate geometries are possible and stable for Zn(II) porphyrin complexes. How do these complexes form and why are they stable when other 5-coordinate geometries of Zn(...
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1answer
82 views

Do all metal nitrates give nitrogen dioxide on decomposition?

Some metal nitrates decompose to give nitrites: $\ce{2MNO3 -> 2MNO2 + O2}$ whereas some metal nitrates decompose to give $\ce{NO2}$. A possible reaction is $\ce{M(NO3)2 -> MO + NO2 + O2}$ Based ...
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1answer
103 views

Balancing redox reaction of zinc and hot diluted nitric acid

I need to balance the following reaction: $$\ce{Zn + HNO3 -> Zn(NO3)2 + NH4NO3 + H2O}$$ I assigned all oxidation numbers: $$\ce{\overset{0}{Zn} + \overset{+1}{H}\overset{+5}{N}\overset{-2}{O_3}\...
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1answer
384 views

Does iron(VI) fluoride exist?

Why does $\ce{FeF6}$ not exist? There are hexavalent iron compounds, so that is not the problem. There is the $\ce{[Fe(CN)6]^3-}$ ion, so there doesn't seem to be a steric problem.
2
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1answer
56 views

How to convert cell diagram to a chemical equation?

How would one convert on the right side of the cell diagram: $$\ce{Zn(s) | Zn^2+(aq) || MnO4-(aq), Mn^2+(aq), H+(aq) | Pt(s)}$$ $$ \begin{align} \ce{Zn(s) &-> Zn^2+(aq)} \tag{ox}\\ \ce{MnO4-(aq)...
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0answers
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Invisible spin allowed transitions in Tanabe-Sugano diagrams

In class we are looking at Tanabe-Sugano diagrams, more concretely at transitions for a d2 complex. I understand that the only spin allowed transitions are those that have a triplet state, therefore ...
6
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86 views

Comparison of C=O bond strength in metal carbonyls

Find the weakest $\ce{C=O}$ bond among $\ce{[Mn(CO)6]+},$ $\ce{Fe[(CO)5]},$ $\ce{[Cr(CO)6]}$ and $\ce{[V(CO)6]-}.$ I thought the $\ce{C=O}$ bond strength would be lowest in $\ce{[V(CO)6]-}$ since the ...
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0answers
28 views

Comparison between bond length of platinum and titanium oxides

This question comes from a problem sheet I recently had. It concerns the fact that Pt-O bond lengths are typically longer than Ti-O ones, even though the radii of the two metals are similar. My ...
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33 views

Why is tetrachlorocuprate (II) yellow if it is high-spin?

From my knowledge of transition metal complexes, tetrahedral complexes generally have less splitting (compared to octahedral complexes) because they only involve four ligands are they aren't placed ...
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0answers
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Why transition metal catalyzed [2+2]cycloaddition reactions allowed?

As you know, cycloaddition reactions which (4n)π electrons are involved in such as [2+2]cycloaddition are forbidden in normal organic reactions, but transition metal catalyzed [2+2]cycloaddition ...
3
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1answer
138 views

Why does green ferrous sulfate solution change color to yellow upon addition of hydrochloric acid?

I was demonstrating the formation of $\ce{Fe(OH)2}$ precipitate at school when the light green $\ce{FeSO4}$ I was using reacted with dil. $\ce{HCl}$ turned yellow. This only happened with dil. $\ce{...
3
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1answer
38 views

Fluorescence quenching by palladium(II) vs. platinum(II) complexes

Why do we observe much stronger (in most cases complete) fluorescence quenching by $\ce{Pd^2+}$ than $\ce{Pt^2+}?$ I work with complexes of both metals and there is no real 100% explanation I can find ...
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1answer
39 views

Why are hydrides of transition metals called hydrogen-deficient?

My textbook states: Metallic hydrides are formed by many d- and f-block elements. Unlike saline hydrides, they are almost always non-stoichiometric, being deficient in hydrogen, for example, LaH$_{2....
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35 views

D block elements electronic configuration

We have found the electronic configuration of d block elements.As we move from left to right in the periodic table the energy of the 3d subshell is decreased and it becomes smaller than the energy of ...
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0answers
64 views

Why do 4d and 5d metals have more orbital overlap than 3d because of size?

When considering the electrical conductivity of metal oxides, they will conduct better if the metals orbitals can reach each other to overlap. Whether this can happen is contributed to by a couple of ...
2
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0answers
113 views

Why does titanium have lower affinity than scandium?

Electron affinity of atoms in the same row usually increases with the atomic number until the shell or half-shell gets full, and then it drops down. Some transition metals are exceptions from the rule,...
0
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2answers
60 views

How tetraamminecopper(II) is formed? [duplicate]

I'm trying to get a sense of how $\ce{Cu^2+}$ and $\ce{NH3}$ are bonded together because it doesn't make any! I understand that $\ce{NH3}$ has a lone pair of electrons that can be donated (right?), ...
3
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1answer
172 views

Magnetic properties of potassium manganate(VII)

According to me, $\ce{MnO4^2-}$ is paramagnetic and $\ce{MnO4^-}$ is diamagnetic. On the basis of this, the corresponding potassium salts inherit these magnetic properties, i.e. $\ce{K2MnO4}$ is ...
5
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0answers
31 views

Is it possible to do Cobalt catalyzed directing group asisted meta C-H functionalization of arenes

Directing Group assisted Pd catalyzed (sp2)meta-C-H functionalization has a growing attention in recent years. In addition, few examples can be found for meta-C-H functionalization via Rhodium. I am ...
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1answer
62 views

Why is the standard enthalpy of formation of aluminium oxide higher than magnesium oxide?

$$\begin{align} &\text{Aluminium oxide:} &\ce{4Al + 3O_2 &-> 2Al2O3} &(\Delta H_\mathrm f &= \pu{-1675 kJ/mol})\\[1.5em] &\text{Magnesium oxide:} &\ce{2Mg + O_2 &-&...
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2answers
61 views

Transition metals with closed shells

From wiki page about valence electrons: An atom with a closed shell of valence electrons (corresponding to an electron configuration $s^2p^6$ for main group elements or $d^{10}s^2p^6$ for transition ...
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1answer
37 views

Do antimicrobial abilities of copper boilers decrease over time?

As copper boilers age and develop oxide buildup, does this lessen the copper's antimicrobial abilities in killing bacteria? I was thinking since that coating would be on the copper, there would be ...
4
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0answers
75 views

Why does my drierite turn bright bright blue, instead of pink?

Drierite a brand name of a commonly-used, calcium sulfate-based dessicant in many chemistry labs. The lab I work in has a dessicator box we use to store hygroscopic materials. It isn't a a true dry ...
7
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2answers
343 views

How to refine manganese metal from manganese(IV) oxide found in batteries? [closed]

I opened up some lantern batteries, and inside there's $\ce{MnO2}$ powder, carbon rods, and zinc casings, and other stuff that I don't know what it is exactly. I scraped out $\ce{MnO2}$-containing ...
5
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0answers
64 views

Wittig reagent with metal–oxo bonds

Could you use the Wittig reagent to attack a metal–oxo bond and replace the oxygen with a carbene? Specifically, is it possible for the Wittig reagent to do σ-bond metathesis with an electrophilic ...
2
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0answers
155 views

How is the UV-visible spectra of carbonatotetraamminecobalt(III) nitrate interpreted?

In a laboratory practice I have done a characterization of the $\ce{[Co(NH3)4CO3]NO3}$ and obtained the following spectra: I don't know if the band between 300 nm and 400 nm can be due to the effect ...
0
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1answer
123 views

Can copper sulfate react with terpenes (such as limonene and terpinenes) at room temperature?

I am just wondering, can I make a metalorganic or organometallic complex of copper and limonene/terpinene/phellandrene in the form of lime oil? If so, what is the formula of the complex formed? I ...
3
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1answer
60 views

In metal complex electron counting, is the neutral or ionic formalism more correct?

I have been practicing finding total valence electron counts by both methods, and a few points have arisen that have confused me. 1) Which method gives the true d-electron count? From what I ...
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0answers
16 views

Why does bonding in T.M complexes get stronger down the group but bonding in p-block elements gets weaker?

In the p-block, it’s a well-known general trend that down the group, the homonuclear diatomic bond dissociation energies decrease (generally). E.g in group 14: C-C —> 607 kJ/mol Si-Si —> 327 kJ/...
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0answers
43 views

Tetrahedral complex and vibronic coupling or different rule for d-d transition?

I'm currently preparing a few slides for an upcoming talk in our group. I would like to mention some of the very basics regarding crystal field and ligand field theory as well, though this will not be ...
-1
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1answer
247 views

Why is HgI2 a colored complex?

Why is $\ce{HgI2}$ a colored complex it has fully filled d-orbits. According to the book, one which has fully filled d-orbital has no color in transition elements. So, why is this compound colored?
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0answers
47 views

Why is molar extinction coefficient for dithiocyanatobis(triphenylphosphine)nickel(II) so high?

I recently looked at a data set where $\ce{[Ni(SCN)2(PPh3)2]}$ had 0 unpaired electrons (from magnetic moment calculation) which indicated to me that it was square planar. I wondered how it could have ...
1
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0answers
21 views

Determining the number of triphenylphosphine ligands in nickel(II) complex

A complex is synthesised by combining hydrated solutions of $\ce{NiCl2}$ $(\pu{0.6 g})$ with $\pu{1.35 g}$ triphenylphosphine $(\ce{PPh3}).$ After cooling the product precipitates as a solid with ...
3
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1answer
57 views

Geometry of the transition metal complex in solid dipotassium bis(oxalato) copper(II) tetrahydrate

I was thinking of the geometry of the transition metal complex in solid $\ce{K2[Cu(ox)2] · 4 H2O}$ solid around the $\ce{Cu(II)}$ ion. At first I thought square planar, but is it possible or is there ...
-4
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1answer
58 views

KMno4 is the strongest oxidizing agent. So why does it tend do have +2 oxidation state with reaction with acids? [closed]

Manganese has an oxidation state of +7 in potassium permanganate. When reacted with sulphuric acid, how does it tend to have +2 oxidation state by forming $\ce{MnSO4}$ along other products ? In acid, ...
0
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1answer
57 views

Bonding in d10 metals such as Zn

I recently learned about the MO bonding model in metals, where many metal atoms form lots of orbitals close in energy that form bands. However, I can't understand the bonding in d10 metals. It seems ...
5
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0answers
102 views

Molecular orbital diagram for carbene-metal and carbodiphosphorane-metal interaction

I am interested in understanding how carbenes and carbodiphosphoranes interact differently with a transition metals. I would like to use qualitative molecular orbital theory arguments (with an ...
0
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0answers
34 views

Beer Lambert law when complex is tetragonal (Jahn-Teller elongated)

I wondered what modifications there would be to the Beer Lambert law to find the molar extinction coefficients for the solution if the solvent contained the ligands which bind to the metal centre of a ...
2
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2answers
329 views

Understanding the Jahn–Teller elongation and compression for octahedral complexes (stabilisation/destabilisation of d orbitals)

I am currently learning about Jahn–Teller effect. For elongation I wondered why the d orbitals with $z$ component are stabilised when the metal–ligand bonds are getting longer? I thought a longer bond ...

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