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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Protrusion of d orbitals to the periphery of an atom
I wanted to know the meaning of the sentence in the NCERT… it goes like this,
‘The d orbitals of the transition elements protrude to the periphery of an atom more than the other orbitals (s&p)..’
...
4
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0answers
136 views
What determines the kind of Bravais lattice structure (body-centred cubic, hexagonal, etc) a transition metal shows?
With the exception of Zn, Hg, Cd and Mn transition metals most transition metals have only one kind of lattice structure at room temperature. Another trend I noticed was that Groups 3 and 4 have ...
2
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0answers
53 views
Why is it that not all metals produce hydroxides when reacting with water? [duplicate]
I was taught, as a rule, that:
metals + water $\rightarrow$ metal hydroxide + hydrogen gas
$$\text{Na} + \text{H}_2\text{O} \rightarrow \text{NaOH} + \text{H}_2$$
However:
$$3\text{Fe} + 4\text{H}...
3
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2answers
757 views
Exchange energy of d6 configuration
In NCERT Chemistry book, it is given as:
Exchange energy is responsible for the stabilization of energy state. Exchange energy is approximately proportional to the total number of possible pairs of ...
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1answer
84 views
How can we predict the formula of a coordination compound by just knowing the ligand and central metal? [closed]
Question:
On complete reaction of $\ce{FeCl3}$ with oxalic acid in aqueous solution
containing $\ce{KOH}$, resulted in the formation of product A. The secondary valency of $\ce{Fe}$ in the product A ...
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0answers
25 views
Does concerted oxidative addition follow first-order kinetics?
So my professor for organometallic chemistry described the different mechanisms for oxidative addition and in talking about the concerted mechanism he said that it had first order kinetics. I find ...
7
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1answer
208 views
How to compare magnetic moment of chromium(III) and cobalt(II) ions?
Is there any way of comparing the magnetic moments of $\ce{Co^2+}$ and $\ce{Cr^3+}$ gas phase ions by just going through their electronic configuration?Or is it just experimental data?
6
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1answer
222 views
Why is it advised to use neutral ferric chloride solution while performing confirmatory test for acetate ions? [duplicate]
The reaction of $\ce{FeCl3}$ with $\ce{CH3COO-}$ is
$$\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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43 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]^...
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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
103 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 ...
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1answer
48 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 ...
2
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2answers
233 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
148 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
67 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
204 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
99 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 ...
2
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1answer
132 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}\...
8
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1answer
392 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.
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1answer
69 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
37 views
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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0answers
125 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
34 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 ...
3
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0answers
38 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 ...
5
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0answers
36 views
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
votes
1answer
266 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
49 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
43 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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36 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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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 ...
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0answers
139 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,...
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2answers
72 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
338 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 ...
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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
86 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
83 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 ...
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0answers
89 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
356 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 ...
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0answers
65 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 ...
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0answers
159 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 ...
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1answer
150 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
62 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
18 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
47 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 ...
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1answer
425 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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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 ...
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0answers
22 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
60 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 ...