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].
480
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23 views
Vanadium redox battery… why not nitrogen redox battery OR iron redox battery?
Vanadium redox battery operating on
$$
\begin{align}
\ce{V^2+ -> V^3+ +e-}\\
\ce{VO2^+ +e- +2H^+ -> VO^2+ +H2O}
\end{align}$$
because Vanadium has multiple oxidation states. How about nitrogen ...
4
votes
0answers
25 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
votes
0answers
72 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 ...
0
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0answers
24 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 ...
-1
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49 views
The complex [Cr(NH3)6]3+ is a high or low spin complex?
Why is it correct to say that this complex $\ce{[Cr(NH3)6]^3+}$ is a high spin complex?
I thought it was a low spin complex because $\ce{NH3}$ is a strong ligand, but in an exercise, I have to explain ...
3
votes
0answers
29 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
votes
0answers
25 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
87 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
votes
1answer
36 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 ...
0
votes
1answer
32 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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32 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
26 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
votes
0answers
108 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
votes
2answers
54 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?), ...
5
votes
0answers
30 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 ...
-1
votes
1answer
45 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 &-&...
0
votes
2answers
50 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 ...
1
vote
1answer
35 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
votes
0answers
67 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
votes
2answers
332 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
votes
0answers
60 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
votes
0answers
146 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
votes
1answer
102 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
votes
1answer
51 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 ...
0
votes
0answers
9 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/...
1
vote
0answers
33 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
votes
1answer
146 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?
1
vote
0answers
44 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
20 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
votes
1answer
53 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
votes
1answer
45 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
votes
1answer
53 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
votes
0answers
69 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
votes
0answers
33 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
votes
2answers
227 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 ...
-1
votes
1answer
97 views
How does chromium behave in a carbonate solution? [closed]
I'm wondering how chromium (as a metal or as a salt) behaves in a concentrated carbonate solution. Will it form any, one or several carbonate specie(s)? Will the metal solubilize? How does it affect ...
-1
votes
1answer
42 views
How to make anhydrous or monohydrate FeSO4 from heptahydrate form?
I need the anhydrous form of $\ce{FeSO4}$ (7720-78-7). I have $\ce{FeSO4.7H2O}$, is there anyway it can be converted to anhydrous form, or at least to monohydrate?
Do you know where I can purchase it? ...
-1
votes
1answer
67 views
What compounds given can oxidize Mn(2+) to MnO4(-)? [closed]
$$\ce{Mn^2+ Solution ->[reagent 'A'] MnO4^-}$$
The reagent '$\ce{A}$' can be
(A) $\ce{Pb2O3 + \text{conc.} HNO3}$
(B) $\ce{K2S2O8}$.
(C) $\ce{(NH4)2S2O8}$
(D) $\ce{K2SO4}$
All of the options can ...
2
votes
0answers
38 views
Ionic radius for tetrahedral metal–ligand complexes
The ionic radii for metal–ligand complexes that are in an octahedral coordination are easy to find. I understand that when the $\mathrm{e_g}$ orbital is filled, the ionic radius increases because the ...
4
votes
2answers
99 views
Transition metal chalcogenides
According to wikipedia, a chalcogenide is a chemical compound consisting of at least one chalcogen anion and at least one more electropositive element. In the same sense does transition metal ...
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0answers
23 views
The quartic electronic state of octahedral Fe(III): How make crystal field splitting diagram?
Using simple arguments from crystal field theory, how do I rationalize the quartic state of octahedral Fe(III)? I am not able to in a logical way distribute the 5 d electrons in such a a way as to end ...
1
vote
0answers
209 views
How can an element have two outermost shells incomplete? [closed]
As I read my book, I saw its written that the Transition metals have two outermost shells incomplete.
But , as I had read earlier, that shells are filled in stepwise manner.
So how is this possible?
...
1
vote
1answer
93 views
Why aren't solid pure transition metals colourful?
I understand that the compounds of transition metal are colourful because of the appropriate energy gap between different d orbitals. But why aren't they also colourful in their solid pure state? For ...
0
votes
0answers
96 views
How can t2g orbital account for extra stability in absence of ligands?
I have read in a book that t2g orbitals sometimes account for stability in 3d block transition elements. For example,
Chromium in 2+ oxidation state shows reducing properties because Chromium in 3+ ...
0
votes
1answer
131 views
Why does this ligand form 6-coordinate complexes with Transition elements and 8-coordinate complexes with Inner transition elements? [closed]
What change takes place in the denticity of this ligand if it is an inner-transition metal ion vs a common transition metal?
Primarily, why does the ligand behaves differently with the two situations ...
2
votes
0answers
41 views
Liquid storage of transition metal oxides?
Transition metal oxides (TMOs) have a lot of interesting properties, from ferroelectricity to battery applications. Often times you can change the properties with only slight changes of oxygen ...
1
vote
0answers
189 views
Manganese oxide reacts with tin(IV) hydroxide?
I have a problem on my chemistry summer homework in which it asks me to predict the product of “solid Manganese-Oxide when it reacts with tin(IV)-hydroxide in aqueous solution”. My issue is that there ...
4
votes
1answer
133 views
Determination of spinel structure by CFSE
$\ce{CuFe2O4}$ has inverse spinel structure, but $\ce{ZnFe2O4}$ has normal spinel structure. Explain.
I know that normal spinels have a structure like $\ce{(A^{II})^{tet}(B^{III})^{oct}_2O_4}$-like ...
6
votes
0answers
64 views
Are platinum metal whiskers very unusual?
Over 20 years ago I pulled my first set of platinum spark plugs out of a car because the engine was missing badly. Two of the six plugs each had one whisker in the gap between electrodes. One crossed ...
5
votes
1answer
112 views
What is the electron count in this nickel complex?
Our class has started learning about electron counting using the ionic method. I was having a little difficulty, especially when there are two metals in one complex, so I looked at Wikipedia for help.
...
