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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Why is MnO2 not a peroxide?

As I know, $\ce{MnO2}$ is called manganese(IV) oxide. Why can't we name it manganese peroxide since manganese(II) exists too? In other words, how do we know that the oxidation number of manganese in ...
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Chromium cyanide complexes

I have rarely seen any chromium $(\ce{Cr})$ square planar complexes and I have been told that $\ce{[Cr(CN)4]-}$ is tetrahedral. So, if the statement is actually correct, are there any other known ...
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662 views

Can one turn a nickel blue?

I've heard of artificial coin toning, but haven't been able to find a recipe for creating a blue (or blue-ish) nickel coin. While not a metallurgist, I work with one. She tried nitric acid, which ...
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484 views

What does the reaction of chromium with ozone form?

I know almost nothing beyond 10th grade chemistry. I'm trying to name a web application, and was wondering what the products are of a reaction between the element Chromium and the gas Ozone (...
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489 views

Is scandium considered a transition metal?

I have seen so many conflicting answers to this question in various places so I wanted to ask it again. IUPAC defines a transition element as an element whose atom has a partially filled d sub-...
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What does the crystal field splitting diagram for trigonal planar complexes look like?

For a trigonal planar complex (e.g. $\ce{[AgCl_3]^2-}$): According to this image (source): The $x^2 - y^2$ and $xy$ orbitals are on the same energy level. However, assuming that one of the $\ce{Cl}$ ...
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Crystal Field Splitting of d-Orbitals in Octahedral and Tetrahedral Ligand Fields

We're learning about the Crystal Field Theory (CFT, under coordination chemistry) at school now, and my teacher mentioned that the 5 d-orbitals split into orbital sets, namely the $\mathrm{t_{2g}}$ (...
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What is the electronic configuration of Fe(II) ion?

The electronic configuration of Fe is $\ce{[Ar] 3d^6 4s^2}$. So after removing two electrons the configuration becomes: $\ce{[Ar] 3d^6}$ But why can't the electrons rearrange themselves to give a ...
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Yellowish tinge during titration of oxalic acid with potassium permanganate

One of the our chemistry practicals involve finding the molarity of an oxalic acid solution by titrating it with standard $\ce{KMnO4}$ solution. The oxalic acid solution is heated and little sulfuric ...
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1answer
442 views

Formation of MnO2 vs [Mn(H2O)6]4+ in aqueous solution

I am looking for reasons why $\ce{Mn(IV)}$ wouldn't be stable as a hydrate. I know that from standard reduction potentials it exists as a ppt of $\ce{MnO2}$, but what is stopping it from being a ...
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Why is hexafluoridonickelate(IV) diamagnetic?

As fluoride is a weak-field ligand, it should not pair up the electrons. So why is $\ce{[NiF6]^2-}$ diamagnetic?
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Why do the halides run in reverse orders in the spectrochemical series and the trans-effect series?

Spectrochemical series: $\ce{F^-}>\ce{Cl^-}>\ce{Br^-}>\ce{I^-}$ Trans-effect series: $\ce{I^-}>\ce{Br^-}>\ce{Cl^-}>\ce{F^-}$ This seems slightly odd to me because their relative ...
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Variable oxidation state of transition metal ions

Transition metals can form stable ions with different oxidation states. But I am confused why doesn't only the most stable state exist. Let me clarify my question more: $$\ce{Ti^{2+} -> Ti^{3+} + ...
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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 ...
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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 ...
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106 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?
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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 ...
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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.
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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-...
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1answer
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Why does copper react only with nitric acid? [duplicate]

When we are entering the chapter for acid and base, one of the reactions is about reacting metal with acid to form a salt and hydrogen gas. My teacher also informed us that a metal which is at a lower ...
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166 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?
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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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Transition metal or transition element?

With reference to the periodic table’s d-block, are the terms “transition metals” and “transition elements” interchangeable when describing these elements? Are there any situations where it would be ...
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Why is zinc deposited on copper when boiling an aqueous zinc sulfate solution?

I did an experiment where I dissolved 30 grams of zinc sulfate in water and boiled it with strips of solid zinc metal and strips of copper metal and a layer of zinc was deposited on the copper. I ...
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What's the configuration of chromium(III) in aqueous medium according to crystal field theory?

It has $\mathrm{3d^3}$ configuration, but how will we decide if they enter $\mathrm{t_{2g}}$ or $\mathrm{e_g}$ orbitals since we don't know which complex will form?
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Stability of 3d metal fluorides and iodides in different oxidation states

I read that the fluorides of 3d metals in lower oxidation states, e.g. $\ce{VF2}$, $\ce{TiF2}$, and $\ce{CuF}$ are thermodynamically unstable. For example, $\ce{CuF}$ disproportionates to $\ce{Cu + ...
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316 views

Which karat gold is harder, 24 kt or 18 kt?

$\pu{24 kt}$ gold indicates that $24/24$ part of it, i.e. $100\%$ of it is gold. $\pu{18 kt}$ indicates that $18/24$ part of it is gold. As gold is a soft element, I reckoned that $\pu{18 kt}$ gold ...
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663 views

Why do better π-acceptor ligands cause smaller Δ(T) d-orbital splitting?

Consider a formazanate ligand. Then imagine an electron-withdrawing group added to it. I expect a small σ-donating effect, and good π-accepting properties. My supervisor tells me that an ...
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482 views

Colorless nature of carbonyl complexes

Researching the coloration of transition metal complexes one day, I came across this reference on Wikipedia 1: I am not sure why this is so. Take $\ce{Mo(CO)_6}$, or any other carbonyl complex of the ...
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1answer
769 views

Jahn-Teller distortion of [Fe(H2O)6]2+

I am wondering whether Fe(II) hydrated to an octahedral complex would undergo a Jahn-Teller distortion. As far as I am aware, this distortion comes about because of asymmetry in filling orbitals, in ...
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Why is ruthenium(III) intensely colored in water

I was preparing a solution of ruthenium(III) chloride (aqueous) when I added some (nearly black) $\ce{RuCl3 . H2O}$ to the water. I was surprised that a tiny amount could dye the water so well, I'd ...
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Method to synthesize KAu(CN)2 (or KCN)?

Every reasonably effective method of electroplating $\ce{Au}$ onto another metal's surface (e.g. $\ce{Cu}$,$\ce{Ni}$,$\ce{Ag}$, etc.) involves use of $\ce{KAu(CN)2}$ or in some cases $\ce{KAu(CN)4}$ ...
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Why is mercury liquid? [duplicate]

Why is mercury the only metal that is liquid at room temperature? Note: I am a high school student and would appreciate an answer, if possible, suited for my level of understanding. Thank you.
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Fractional index in a chemical formula of metal oxide

I have just read an article in which they used $\ce{WO3}$ and $\ce{WO_{2.9}}$ as precursors, whose objective was to form $\ce{WS2}$, in an atmosphere of argon by CVD. In one boat there is the powder ...
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Why is the tetraamminecopper(II) ion square planar?

The tetraamminecopper(II) ion is square planar in shape. But why? How can I rationalise this? Can I rationalise this without the concept of hybridization? And even if I take hybridization into ...
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Why does copper(II) carbonate decompose into copper(II) oxide rather than copper(I) oxide when heated?

I recently did a lab at school surrounding the decomposition of copper(II) carbonate into copper(II) oxide, and subsequently into pure copper, when sufficient heat is added. What I don't understand is ...
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Why do heavier transition metals show higher oxidation states?

In p-block elements, higher oxidation states are less stable down the group due to the inert pair effect. This is not the case for transition metals. Why do heavier transition metals show higher ...
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611 views

Transition Metal Compounds [closed]

So I have a few dumb questions. I'm still in high school and am doing something on magnetic properties of transition metals. I'm facing a few roadblocks. 1) What're compounds like $\ce{CoBr2, CoCl2, ...
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Why does density decrease across the period 4 and 5 transition metals?

I know that density decreases across period 4 because the last two elements are liquids and gases which means that their densities are less but why are the densities increasing and then decreasing ...
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695 views

Why do complex ions not emit light from de-excitations of electrons?

I understand that complex ions are coloured due to d-orbital splitting which results in electrons being able to absorb wavelengths of visible light and become excited to the higher energy state ...
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Problems with precipitation of transition metal solution

I am trying to make a solution of "trace elements"--primarily transition metals-- for use in biological media; bacteria require elements like Cobalt, Molybdenum, iron, etc. in trace amounts. I am not ...
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1answer
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Reaction of iron(III) oxide with nitric acid [closed]

I'm currently working in a project in which I have to convert the iron oxides present in iron ore slime into ferric nitrate. Iron ore slime is which has the particle size of below $\pu{0.15 mm}$ is ...
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1answer
651 views

Is the colour of leaves due to d-d transitions in chlorophyll?

While reading a chapter on transition metals, I came to know that d-Block elements have colour compounds due to d-d transitions. A question came to my mind as to whether there is any d-d kind of ...
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What makes a ligand stronger than another?

A ligand is a neutral molecule or negative ion with at least one lone pair of electrons which forms a dative covalent bond with a complex ion that has a vacant, energetically accessible orbital. It ...
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1answer
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Why are fluorides of transition metals unstable in low oxidation states? [duplicate]

Why are fluorides of transition metals unstable in low oxidation states? I would think that since fluorine and oxygen are highly electronegative, it's obvious that they be stable at high oxidation ...
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1answer
106 views

Palladium Nanocube

What is the relative permittivity and relative permeability of a palladium nanocube? If I change the size of this $\ce{Pd}$ nanocube, will these values be changed or remain the same?
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Protein purification with Cobalt

Cobalt exhibits a more specific interaction with histidine tags, resulting in less nonspecific interaction than nickel. For this reason, cobalt is the preferred divalent cation for purifying His-...
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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 $\ce{Au-N}$ ...
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Considering the d-d transition how, does tetracyanidonickelate(II) ion exist as a colored complex?

As I refer on google, the resources indicated that, the d block elements which have unpaired electrons as in their ions, when they are making complexes with ligands, they can absorb different ...
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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?...

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