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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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1answer
64 views

Conditions for the reduction of dichromate by manganese(II) to chromium(III) [closed]

The unbalanced redox reaction $$\ce{Mn^2+ + Cr2O7^2- -> Mn^3+ + Cr^3+}$$ occurs in what type of condition? (a) Acidic (b) Basic (c) Neutral (d) Indeterminable
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1answer
63 views

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
93 views

Can concentrated sulfuric acid oxidize iron(II) to iron(III)?

Can concentrated (18 M) $\ce{H2SO4}$ oxidize $\ce{Fe^2+}$ to $\ce{Fe^3+}?$ Or does it actually block the oxidation? I read in some forum somewhere that in order to prevent $\ce{Fe^2+}$ from being ...
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1answer
45 views

Cupric and cuprous copper [duplicate]

Copper has two chlorides: $\ce{CuCl2}$ and $\ce{CuCl}.$ Copper reacts directly with chlorine to form a copper(II) chloride. Why doesn't it form copper(I) chloride? Is it because $\ce{CuCl2}$ is more ...
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2answers
69 views

How to know dichromate is being reduced from Cr⁶⁺ to Cr³⁺?

When potassium dichromate is being used as an oxidising agent, it gets reduced from chromium(VI) to chromium(III). Is there any way to know that or calculate that other than being familiar with ...
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1answer
835 views

What is the hybridization of chromium in chromate and dichromate ions?

I was recently reading about the transition metals and some important compounds of them. I came across a rather interesting diagram in my book... a tetrahedral structure for the chromate ion. The only ...
56
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4answers
42k views

How can one explain niobium’s weird electronic configuration?

As cited in an answer to this question, the ground state electronic configuration of niobium is: $\ce{Nb: [Kr] 5s^1 4d^4}$ Why is that so? What factors stabilize this configuration, compared to ...
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1answer
10k views

Why is Cr²⁺ is a good reducing agent but Mn³⁺ is a good oxidising agent?

The question is the same as the title states. In my text book,the following is written $\ce{Cr^{2+}}$ gets converted to $\ce{Cr^{3+}}$ as the +3 oxidation state hase half filled $\mathrm{t_2g}$ ...
12
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1answer
541 views

What is the Structure of FeSO₄ • NO?

What is the structure of $\ce{FeSO4 \cdot NO}$ that is formed when $\ce{NO}$ is passed through ferrous sulfate solution? If it is a brown ring complex then why does the complex sphere break upon ...
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1answer
50 views

CO-vibration in metal carbonyl

I'm struggling to understand the trend of $\ce{CO}$-vibration in isoelectronic metal carbonyls. $$ \begin{array}{lr|lr} \hline \text{Compound} & ν/\pu{cm-1} & \text{Compound} & ν/\pu{cm-1}...
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2answers
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Synthesis of potassium trioxalatocobaltate(III) trihydrate

I've synthesized the compound potassium trioxalatocobaltate(III) trihydrate and for it I have two reaction equations. One of them is: $$\ce{CoCO3 + 3K2C2O4.2H2O -> K2[Co(C2O4)3] + 2CO2}$$ and the ...
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1answer
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What is the oxidation state of Mn in HMn(CO)5?

What is the oxidation state of $\ce{Mn}$ in $\ce{HMn(CO)5}$? If $\ce{H}$ has an oxidation state of $+1$, then $\ce{Mn}$ should have oxidation state of $-1$, which I'm not sure is possible. On the ...
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4answers
21k views

Why is zinc more reactive than copper?

In terms of electronegativity, from what I understand electronegativity increases going across the period, so surely this should mean that zinc less readily loses its outer shell electrons than copper?...
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0answers
170 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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0answers
25 views

Nature of the bonding in hexaaquaaluminium complex

$\ce {[Al(H2O)6]^3+}$ is a well-known complex ion formed by the $\ce {Al^3+}$. I have always had the understanding that only the aqua complexes of transition metal ions, such as $\ce {[Fe(H2O)6]^3+}$, ...
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0answers
71 views

Why decanted solution should be colorless when determining formula of unknown chloride?

I was following the guide “Stoichiometric Determination: Empirical Formula of Copper Chloride”. Under the Procedure section the following reaction is given: Producing solid $\ce{Cu}$ from a $\ce{Cu(...
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0answers
68 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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Does tantalum and tungsten really not form amalgams?

User @Poutnik has recently answered two questions(here and here) in which he/she quoted this statement from Wikipedia: Almost all metals can form amalgams with mercury, the notable exceptions ...
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4answers
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Why are there 14 electrons in the third shell of iron atom?

The third shell must contain at least 18 electrons. But in iron there are 14 electrons in third and 2 electrons in 4th. Why are there 14 electrons in the third shell of iron atom?
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1answer
121 views

Molar conductivity of transition metal complexes solutions [closed]

Which of the following has the highest molar conductivity? (A) Diaminedichloroplatinum(I) (B) Tetraamminedichlorocobalt(III) chloride (C) Potassium hexacyanoferrate(II) (D) Hexaaquochromium(...
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0answers
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Oxidation of Hexaaquachrom (II) with air

I had the reaction: $$\ce{Cr(H2O)6^3+ -> Cr(H2O)6^2+}$$ using $\ce{Zn}$ as a reducing agent. the colour turning from green to blue and I know that with contact with air the solution becomes ...
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1answer
310 views

Products of the reaction between chromium(III) chloride, zinc and sulfuric acid

The aim of my experiment was to make a Cr(II) aquacomplex in situ, and for that I have the reaction: $$\ce{CrCl3·6H2O + Zn}$$ and I add concentrated sulfuric acid to it. I know that chromium(III) ...
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2answers
85 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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0answers
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What chemical reaction could be used to make copper pennies a vibrant red?

I’m an artist working on a piece using pennies to illustrate my drawing and I need my pennies to be red in a certain portion. I’m trying not to use paint and was wondering if there was a way to make ...
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1answer
59 views

Reaction of coloured metal complexes with water and sulfuric acid [closed]

Reaction of coloured metal complexes with water and sulfuric acid I recently started researching the coloured compounds made from transition metals focusing on one with oxidation state II, so Mn,Fe,...
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0answers
511 views

Definition of early vs. late transition metal

Is there an accepted definition of an early or late transition metal? I think the late transition metals start at Group 8 (including Fe), but others have said Fe is not a late transition metal. I'm ...
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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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2answers
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Why is Ni[(PPh₃)₂Cl₂] tetrahedral?

Since PPh₃ is strong field ligand and, the famous Wilkinson's catalyst, which also possess this ligand is square planar, then what makes the above complex tetrahedral?
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1answer
101 views

Reference for electronegativities of different metal oxidation states

A long time ago I was researching the effect of the self regulatory response in Fe and Co. I found that my results made sense based on the idea of the electronegativity of the ions considered. I found ...
5
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2answers
865 views

Why is the ground state electronic configuration of Group 10 (Ni group) elements so anomalous?

While studying about d block elements I came across this table showing outer shell electronic configuration of group 10 elements $\ce{Ni}$ $ $ $ $ $ $ $ $ $ $ $3d^8$ $4s^2$ $\ce{Pd}$ $ $ $ $ $...
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0answers
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Why do tetrahedral organic molecules show stereo-isomerism, but not tetrahedral transition metal complexes?

Both types of molecules show different arrangements of the molecule in space, so they should qualify for optical isomerism right?
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1answer
253 views

Why do some ions form tetrahedral complexes more readily than others? [closed]

Why does Co$^{2+}$ readily form tetrahedral complexes such as [CoCl$_4$]$^{2-}$, whereas Fe$^{2+}$ usually forms octahedral complexes?
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1answer
54 views

Why is the reason for color different in these two cases? [closed]

I have read in a book (NCERT India) about flame color for salts of alkali metal and color of transition metal complexes. In the first case, it says that during excitation of electrons to higher ...
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0answers
154 views

Why does copper jewelry & wire smell bad - even when I'm not wearing it? [duplicate]

I make jewelry by weaving a frame from copper wire for a gemstone, then making copper coils or spirals, etc for further decoration. Even 'on the roll', the copper wire smells bad - and the smell ...
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0answers
27 views

Why do heavier d block elements are more stable in higher oxidation states than lighter d block elements? [duplicate]

I read that it is because it is easier to ionise the elements as the electrons involved are those of d orbitals which have same degeneracy. First of all, i found it very vague. Secondly, what about ...
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0answers
41 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
36 views

Metal complexes and bonding of ligands

I am currently learning about transition metal complexes, however I keep seeing complexes like $\ce{[Al(H2O)6}]^{3+}$ but aluminium isn't a transition metal. Is this a case that any metal can form a ...
2
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2answers
319 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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0answers
782 views

What is the chemistry behind black colour of platinum black? [duplicate]

Platinum is a silvery white metal and is highly unreactive then why it's powdered form "platinum black" is platinum metal but is black in colour. why would a metal such as platinum become black as a ...
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0answers
115 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 ...
2
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1answer
884 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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0answers
17 views

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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1answer
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How to convert soluble colorless [HgI₄]²⁻ back to insoluble red HgI₂? [closed]

When a solution contains $\ce{Hg^2+}$ and $\ce{I-}$, depend on the concentration ratio of $\ce{Hg^2+}$ and $\ce{I-}$, the following reactions can happen: $$\ce{Hg^2+ + 2 I- ⟶ \underset{insoluble red ...
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1answer
3k views

Why does the Co³⁺/Co²⁺ couple have such a high reduction potential?

Cobalt is changing from $\mathrm{(3d)^6}$ to $\mathrm{(3d)^7}$ electronic configuration. What's so stabilizing about that? Just by reduction potentials this couple is more oxidising than hydrogen ...
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3answers
639 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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0answers
112 views

ML6 Type Coordinate Complexes - Drawing a Molecular Energy Orbital Diagram

In class we recently discussed how to draw out molecular orbital energy diagrams for compounds such as NH3 (ammonia). Building upon this, we touched on how to construct a molecular energy diagram for ...
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17k views

Mechanism for an Étard reaction (chromium complex)

In the following reaction, a chromium complex is formed during the Étard reaction: I have the following questions: How is this complex formed? How does its hydrolysis take place? (What's the ...
2
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2answers
8k views

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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0answers
93 views

Qualitative analysis of iron(III) salt

Why will $\ce{Fe^3+}$ give brown ring test? In my textbook it was given that ferric ion gives brown ring too. I am confused, if ferric ion is already present, then what will reduce nitrate ion to ...
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1answer
960 views

Why do the f-block elements ( inner transition metals) have an oxidation number of +3? [closed]

The f-block valence electrons understandably include the outermost two from 6s. But why do the f-block elements have an oxidation number of +3, pulling an electron from an inner shell, not even a d-...