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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What is the most common oxidation state of gold?

I had a test this morning which had the following question: What is the most common oxidation state for gold? (a) +1 (b) -1 (c) +2 (d) +3 Since the electronic configuration of $\ce{Au}$ is $\...
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1answer
779 views

How to determine the greatest d orbital splitting?

This question comes specifically from an IB Chemistry HL Paper 1 in May 2018 TZ1, namely question 8. Which complex has the greatest d orbital splitting? It gives 4 Complexes $\ce{[Fe(H_2O)_6]^{2+}}$,...
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2answers
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Why does ligand exchange take place? [closed]

Why does ligand exchange happen? Are there specific factors that determine when a ligand can replace another ligand? When ligand exchange takes place, does that mean that the "previous" ligand is ...
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261 views

Colour change when excess ammonia added to [Cu(H2O)6]2+

Since ammonia is a stronger ligand than $\ce{H2O}$ shouldn't the colour of the new solution $\ce{[Cu(NH3)4(H2O)2]}$ be lighter as the energy gap will be higher and so light with higher frequency and ...
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2answers
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Why is lead sulfide found in nature, whereas lead oxide is less common?

This question probably applies to other heavier metals as well. The only rationalization I can figure is that lead in the +2 oxidation state (which is most common) is a borderline soft acid and ...
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2answers
82 views

Colour of metal complexes with the same type and number of ligands

Crystal Field Theory says that because of d-orbital splitting caused by different ligands we have 2 different energy levels for d-orbitals. It also says that transition metals are coloured because ...
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1answer
667 views

Why is the iron(II) on the heme molecule depicted as having 6 electrons in its 5 d non- and anti-bonding orbitals?

Approximating the $\ce{Fe}$ complex as a square base pyramid ($D_\mathrm{4h}$ symmetry) with 5 $\ce{N}$ ligands, My electron count of the system gives me 16 electrons – 10 from the $2\times 5$ $\ce{N}$...
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Why are transition metals said to have different valencies?

I understand that the term valency refers to the number of bonds an element would be able to form with either chlorine or hydrogen. If this is directly related to the number of valence electrons an ...
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2answers
931 views

Why does mercury in mercuric acetate have a lone pair?

The configuration of mercury ends with $6s^{2}$. In mercuric acetate, mercury is in the +2 oxidation state, so does it still have a lone pair?
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626 views

How can I understand the Lewis acid-base interaction of iron(III) and water?

The interaction between $\ce{H+}$ and $\ce{NH3}$ as respectively a Lewis acid and a Lewis base is clear for me. $\ce{NH3}$ has a lone electron pair and $\ce{H+}$ has no electrons, or, saying politely, ...
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568 views

In crystal field theory, why do all the metal electrons enter the d orbitals and not the s orbital?

Suppose we have the complex $\ce{[Fe(H2O)6]}$. Iron has 26 electrons, and its electronic configuration is therefore $[\ce{Ar}]\,\mathrm{4s^2 3d^6}$, but in crystal-field theory, we say that the $\...
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Colour of Nickel thiocyanate

What is the colour of $\ce{C2N2NiS2}$ (Nickel thiocyanate)? In most of the web sites it only molecular weight,formula and other specifications but its colour is missing every where.
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Why does the displacement reaction of zinc in copper(II) sulfate solution result in dark metallic copper?

It is commonly known that when zinc metal is placed in a solution of copper(II) sulfate, a displacement reaction occurs, and elemental copper is deposited onto the decomposing zinc metal. A practical ...
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1answer
427 views

Low-spin / high-spin arguments: why overlooking pairing energy?

There are many arguments in inorganic chemistry based on a transition from a high-spin to a low-spin configuration, for example: $K_{f,3} > K_{f,2}$ for $\ce{Fe(bipy)3}$ complex, because of "a ...
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1answer
181 views

General notation for one of the d-orbitals

What is the general notation to represent the d-orbital with $l=2$, $m_l=0$, i.e. the orbital normally referred to as $\mathrm{d}_{z^2}$. To elaborate more, this orbital can be ordered in various ways ...
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1answer
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Why Gold and Silver react minimally with atmosphere?

Gold and Silver atoms interact with one another to form reasonably strong metallic bonds, but surprisingly they have almost no chemical interaction with atmosphere. How can we explain it based on the ...
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1answer
36 views

Flame test for copper salts

I have read from sources here, here and even in my textbook that Copper (specifically $\ce{CuCl2}$ ) burns with a bluish green flame. All the sources mention that this is due to electron excitation ...
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1answer
6k views

Does crystal field splitting energy Δ increase going down a group of transition metals if the ligands are weak field?

Going down a group, the metal orbitals are more diffuse so there is greter overlap between the metal and the ligand orbitals. If there are no π-interactions, i.e. with σ-donor ligands like $\ce{NH3}$, ...
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1answer
442 views

Orbital mixing in square planar D4h complexes

Consider a square planar $\ce{ML4}$ complex with $D_\mathrm{4h}$ symmetry. Which orbital should the $\mathrm{a_{1g}}$ SALC of the ligands mix with, $\mathrm{3d}_{z^2}$ or $\mathrm{4s}$? Both of those ...
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1answer
2k views

Reaction of Cu in hydrochloric acid bath with exposure to air over several months?

I assume that copper will be slowly oxidized by oxygen, dissolved in water, forming copper(I) oxide (as stated here): $$\ce{4 \overset{\pm0}{Cu} + O2 -> 2 \overset{+I}{Cu}_2O}$$ Reaction rate ...
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1answer
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Magnetic moments of tetrahedral Cobalt (II) and (III) complexes

From the spin-only formula we can predict that for tetrahedral cobalt (II) complexes $$m_{eff} = 3.87 \mu_B $$ This ignores orbital angular momentum effects, which result in higher magnetic moments ...
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Why is Technetium unstable?

Technetium is probably the most awkward element of the periodic table for me. It seems to me that Technetium is an exception, in the sense that it doesn't have any stable isotopes, despite having a ...
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Heating CrCl3(bpy)3 — isomerism and ligand exchange

$\ce{CrCl3(bpy)3}$ (A) when heated forms (B) which has the formula $\ce{CrCl3(bpy)2}$ and has one free $\ce{Cl-}$ per mole of (B). B can react with ethylene diamine ($\ce{en}$) to form (C) which has ...
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1answer
793 views

Ligand exchange reactions… are they one way or reversible?

Are ligand exchange reactions one-way reactions or reversible? I know this is a very silly question but its not said outright in any place... For example, in my high school chemistry book, these two ...
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1answer
74 views

What happens when ferric chloride is dissolved in water?

Ferric chloride can be prepared by dissolving hematite in hydrochloric acid: $$\ce{Fe2O3 + 6HCl -> 2FeCl3 + 3H2O }\tag{1}$$ But the resulting ferric chloride will be exposed from its formation to ...
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1answer
293 views

ligand pi system irreducible representation for trigonal bipyramidal transition metal complex

I am considering a D$_{3h}$ trigonal bipyramidal transition metal complex MX$_5$. I have found that the irreducible representation for the ligand s and $\sigma$ systems is 2A$_1'$+A$_2''$+E$'$. I ...
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1answer
704 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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1answer
147 views

Do the compounds NaₓIrO₂ and NaOsO₂ exist?

Based on some physics background, I want to know whether have scientists synthesized these two materials: $\ce{Na_{$x$}IrO2}$ and $\ce{NaOsO2}$ in the lab, if so, what properties do they have? I ...
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1answer
682 views

Bonding in a bridged metal carbonyl

Can someone please explain the bonding in a bridged metal carbonyl (like diiron nonacarbonyl)? I cannot understand what kind of bonds (sigma/pi) exist between the bridging carbonyls and the metals. ...
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1answer
71 views

Aqueous copper and how it reacts with NH3

I have learnt that you can test whether an unknown metal is copper by doing a simple test tube reaction. The reaction involves adding aqueous $\ce{NH3}$ to the test tube which contains the copper. ...
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2answers
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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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1answer
707 views

How can I dissolve nickel(II) oxide?

To insulate $\ce{Pt}$ wire heaters, I plated them with $\ce{Ni}$. After switching on the heater for the first time, green $\ce{NiO}$ is formed which is insulating and protects the $\ce{Pt}$ from ...
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1answer
388 views

Pb-based pigments and rhodizonate salts

In a previous question, I learned that we can detect lead with sodium / potassium rhodizonate, giving a nice purple color when reacting with pure (elemental?) lead. But in the paint, lead is ...
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0answers
99 views

Explain why can't zinc be plated out from a Zn(II) solution using standard reduction potentials

I am currently learning about electrochemistry using Zumdahl's Chemistry [1, pp. 709–710]. One of the critical thinking questions is Why can $\ce{Zn}$ not be plated out from an aqueous solution of $...
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48 views

Factors that influence the electrical conductivity of metals

The electrical conductivity of metals is a physical property of these materials. Much of the theory used to explain the electrical conductivity of metals is also based on physics understanding. ...
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1answer
92 views

Mixing cobalt(III) hydroxide and thallium(III) hydroxide

A simple question on solutions is driving me crazy. At this point, I think the textbook's wrong. Here's the question: A saturated solution of cobalt(III) hydroxide $(K_\mathrm{sp} = \pu{1.6e-44})$ ...
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0answers
36 views

Reactivity of Ni Vs. Pd - available oxidation states

I'm hoping someone can help me tighten up my understanding of the origins of the differences between Ni and Pd catalysis. I understand that Ni has higher charge density and this is the reason for it'...
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0answers
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Metal catalysts used in C-H bond functionalisation [closed]

Why are the late transition metals used for C-H bond activation/functionalisation? What atomic properties of the late TM make them attractive for coordinating C-H sigma bonds? Thanks.
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Can hexavalent chromium be created by exposure of chromium alloys to air at room temperature?

I believe that Cr on its own (as in chrome coating) oxidizes as Cr(III) when exposed to air, and similarly I think that it is the same for Cr as a component of stainless steel. Is it always the case ...
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2answers
853 views

Density of d-block elements

Something that confuses me slightly is the trends in density when comparing periods 4, 5, and 6 in the d-block. Looking at periods 5 and 6, the density peaks at group 8, with ruthenium and osmium, ...
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260 views

Molecular orbital diagram for terminal metal-oxo complex with dative bonds

I am interested in terminal metal-oxo complexes and their electronic structure, specifically those with coordination numbers of 6, including the oxo ligand. I know that Fe(IV)-oxo complexes tend to ...
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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'...
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30 views

Trend in the infrared stretching of molecular hydrogen to group 8 transitions metals?

While going through old notes, in relation to the Dewar-Chatt-Duncanson model, it states that the stretching frequency for $\ce{N2}$ to the group 8 transition metals ($\nu(\ce{NN})$) proceeds as: \...
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249 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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262 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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0answers
101 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
56 views

CF and MO theories: seeing connections between the two approaches

I wonder if and how when considering MO theory, we are accounting for the electrostatic interaction / repulsion between electrons on the metal and the ligand. It seems like MO assumes pure covalency, ...
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338 views

Are d electrons ever delocalized in metallic bonding

It has been my understanding that delocalized electrons that participate in metallic bonds come from the highest primary energy level, specifically from the s and p sublevels and that electrons in d ...
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0answers
35 views

Why some hydrates are coloured while other are not [duplicate]

I was studying about different vitriol and noticed that some hydrates are coloured while some are colourless even after having water in their crystals. For example; $\ce{FeSO4.7H2O}$ (iron sulfate ...
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0answers
101 views

Selectivity of catalysts

What is the reason behind the fact that methane on controlled oxidation gives methanol in presence of Cu catalysts whereas formaldehyde is obtained if we use molybdenum oxide ($\ce{Mo2O3}$)? IUPAC ...