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].

116 questions with no upvoted or accepted answers
Filter by
Sorted by
Tagged with
12
votes
0answers
316 views

What is d-orbital collapse?

When I was perusing the works of Schwarz on atomic structure, I came across the unfamiliar term of d-orbital collapse. He describes it as a variation in energetic sequence from group 1 to 3 elements ...
9
votes
1answer
3k views

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} > ...
8
votes
0answers
465 views

Why does tantalum and tungsten not form amalgam?

User @Poutnik has recently answered a question in which he/she quoted this statement from Wikipedia: Almost all metals can form amalgams with mercury, the notable exceptions being iron, platinum, ...
6
votes
0answers
98 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 ...
6
votes
0answers
70 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 ...
6
votes
0answers
819 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 ...
6
votes
0answers
35 views

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 ...
6
votes
0answers
6k views

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.
6
votes
0answers
4k views

Is iron(III) carbonate stable in water?

I searched for this onsite already, and also found the following answer on Quora: In aqueous environment, iron(III) is bound by water molecules and exists as $\ce{[Fe(H2O)6]^3+}$. Due to strong ...
6
votes
0answers
181 views

I found transition states (TS), but calculations aren't supported by experiment. Do I look for more TSs or somewhere else?

I'm using Gaussian to investigate a catalyst system. Experimental evidence showed that one of three analogues (R = phenyl, Ph), yielded a benzosultam when treated with 2,4,6-...
6
votes
0answers
789 views

Why are the electronegativities of transition metals so similar to each other?

I was wondering why the electronegativity among transition metals are so similar. I can't find anything on the internet, just vague answers about the d orbitals that don't seem to provide a sufficient ...
5
votes
0answers
89 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 ...
5
votes
0answers
33 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 ...
5
votes
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 ...
5
votes
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 ...
5
votes
0answers
105 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 ...
5
votes
0answers
2k views

Why is hexacyanoferrate(II) colored and at the same time diamagnetic?

I am wondering why $\ce{[Fe(CN)6]^4-}$ is colored and at the same time diamagnetic. For a transition metal to be diamagnetic all the electrons should be paired up in the d orbitals and at the same ...
5
votes
0answers
43 views

Cytotoxicity of Ru-complexes

I have a basic question: why are Ru(II)-complexes cytotoxic? What I know is that depending on the used ligand some of them interact with the DNA either via DNA-pi-stacking (intercalation) or binding ...
5
votes
0answers
145 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 ...
5
votes
0answers
113 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?
5
votes
0answers
397 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 ...
5
votes
0answers
149 views

Asymmetric Suzuki coupling - saturated alkyl chain

9-BBN is applied for Suzuki coupling of a saturated alkyl chain with some alkenyl,alkynyl or even secondary alkyl halide like the modification attached: (Saito, B.; Fu, G. C. Alkyl−Alkyl Suzuki Cross-...
5
votes
0answers
204 views

How to rationalise the trend in the covalent radii of the transition metals?

Why do the covalent radii of transition series decrease at the start rapidly, then become almost constant and at the end of series begin to increase from left to right in periodic table?
4
votes
0answers
35 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 ...
4
votes
0answers
83 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 ...
4
votes
0answers
48 views

Rhombohedral second-order Jahn–Teller effect in Au(II) complex?

I was recently listening to a talk about the following work[1] when the author mentioned that they explained the following. In this $\ce{Au(II)}$-porphyrin complex you observe two sets of $\ce{Au-N}$ ...
4
votes
0answers
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 ...
4
votes
0answers
3k views

Why is the geometry of [Ni(CN)4)]2- square planar? Why is it colorless?

Why is the geometry of $\ce{[Ni(CN)4)]^{2-}}$ square planar given that it has a coordination number of 4? Shouldn't its geometry be tetrahedral as it would minimise the bond angle and hence repulsion?...
4
votes
0answers
529 views

Why doesn't beta hydride elimination happen in alkenyl/aryl halides?

Beta hydride elimination is an important reaction in organometallic chemistry: This reaction prohibits the use of saturated alkyl halides in coupling reactions, because it can take place after ...
4
votes
0answers
617 views

Can oxidation of ethanol by copper(II) oxide yield copper(I) oxide as one of the products?

We know that ethanol is oxidised by copper(II) oxide to an aldehyde. Copper is reduced from $\ce{Cu^2+}$ to $\ce{Cu}$. Can this reaction, with some specific condition, yield $\ce{Cu2O}$ instead? That ...
4
votes
0answers
9k views

NO coordination linear vs bent - valence electron

I'd like to count the total valence electron of following neutral complex in the ionic counting (=donor-pair): Electron count: $$\begin{align} \ce{Cl-} : \ce{6e-} \\ \ce{CH3-}: \ce{2e-} \\ \ce{PPh3} :...
3
votes
0answers
35 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 ...
3
votes
1answer
39 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 ...
3
votes
0answers
236 views

Why are the Covalent Radii of Ruthenium and Osmium So Similar?

Osmium and Ruthenium have covalent radii 144 and 146 respectively (according to Wikipedia). How are these values so similar when Osmium has 32 more electrons, with another filled p, s, and f orbital ...
3
votes
0answers
144 views

Dilute FeCl3 colour is darker at 5e-4M than at 5e-3M. Why?

I did two different dilutions of $\ce{FeCl3}$ (within a $\pu{1h}$ timespan) from $\pu{0.05 M}$, and the one with $\pu{5E-4 M}$ concentration looked a darker orange than the one with $\pu{5E-3 M}$. ...
3
votes
0answers
7k views

The irregular trend in ionization enthalpy of 3d elements

The d block elements display several exceptional behaviours, and one of them is the irregular trend in ionization enthalpy of 3d elements. The reason given by my textbook is very confusing, which I'...
3
votes
0answers
66 views

Why does some compound as given in the image below change from low spin to high spin above a particular transition temperature?

Magnetic moment sudden increase at a particular temperature is explained by CFT. But why does it happen at all?
3
votes
0answers
392 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?
3
votes
0answers
159 views

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 ...
3
votes
0answers
42 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 ...
3
votes
0answers
205 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 ...
3
votes
0answers
58 views

How do partially protonated sulfate ligands affect a metal's charge?

I'm currently reviewing the Periana-Catalytica system and I have a question about one of the intermediates, namely $\ce{[(bpym)Pt(OSO3H)2]^+}$, which is found in the following tutorial review. How do ...
3
votes
0answers
218 views

Why do isomeric bis-ethylenediamine cobalt complexes react differently?

A compound $\ce{Co(en)2(NO2)2Cl}$ has been prepared in a number of isomeric forms.One form undergoes no reaction with $\ce{AgNO3}$ or $\ce{(en)}$ and is optically inactive. A second form reacts with $...
3
votes
0answers
1k views

How can I dissolve copper but not zinc?

I have a zinc-body garden spray head with a brass garden hose thread stuck inside. This is actually an irritatingly common problem. Which got me wondering: What chemical means exist to dissolve ...
3
votes
0answers
130 views

Iron (II) dioxygen reaction mechanism?

Ok so I'm confused about the mechanism for this process: Now the idea here is that iron first becomes oxidised to Fe(III) by placing an electron in the antibonding orbital of dioxygen. This is ...
3
votes
0answers
44 views

Is hydrolytic polymerisation the mechanism by which the precipitate forms from the neutral complex?

From basic coordination chemistry and acid-base equilibria we understand that a metal hexa-aqua ion can be deprotonated until it's positive charge is balanced by the negative charge of the hydroxides ...
2
votes
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(...
2
votes
0answers
136 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,...
2
votes
0answers
157 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 ...
2
votes
0answers
40 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 ...