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Why is it wrong to use the concept of hybridization for transition metal complexes?

Tetrahedral complexes Let's consider, for example, a tetrahedral $\ce{Ni(II)}$ complex ($\mathrm{d^8}$), like $\ce{[NiCl4]^2-}$. According to hybridisation theory, the central nickel ion has $\mathrm{...
orthocresol's user avatar
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31 votes
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What is the perfect definition for chirality?

The correct definition of chirality is given in the IUPAC gold book as follows: chirality The geometric property of a rigid object (or spatial arrangement of points or atoms) of being non-...
Martin - マーチン's user avatar
27 votes

What is the perfect definition for chirality?

I think Martin has provided an excellent answer, and I would like to supplement it with a few additional details and examples that might prove insightful. So as I already mentioned in the comments, ...
getafix's user avatar
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23 votes
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Why is manganese(II) coloured although the transition should be spin-forbidden?

Selection rules The intensity of the transition from a state $\mathrm{i}$ to a state $\mathrm{f}$ is governed by the transition dipole moment $\mu_{\mathrm{fi}}$ (strictly, it is proportional to $|\...
orthocresol's user avatar
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22 votes

Why isn't the orbital angular momentum also considered while calculating the magnetic moments 3d transition elements?

Simplistically speaking orbital angular momentum is present when some conditions are satisfied: A set of orbitals are degenerate; These orbitals can be "interconverted" by rotation about a certain ...
orthocresol's user avatar
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22 votes
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Explanation for why nickel turns green in hydrochloric acid

The question is really badly worded. For starters, let’s look at solutions of nickel(II): Figure 1: Nickel(II) solutions. From left to right: $\ce{[Ni(NH3)6]^2+}$, $\ce{[Ni(en)3]^2+}$, $\ce{[NiCl4]^2-...
Jan's user avatar
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19 votes
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Can Fe(CO)5 adopt both square pyramidal and trigonal bipyramidal geometries?

Your book was correct that a five coordinate metal complex is able to adopt both square pyramidal and trigonal bipyramidal geometries, and in both cases the sp3d hybridisation scheme applies (if you ...
NotEvans.'s user avatar
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19 votes

Where does the label ‘Dq’ to denote the field split in coordination compounds come from?

I will expand my previous comment into an answer. In the $O_h$ case the metal ion is surrounded by $6$ ligand ions, each with charge $q=-Ze$ located at $\langle\pm a,0,0\rangle$, $\langle0, \pm a,0\...
user5713492's user avatar
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18 votes

Usage of ammine vs amine in nomenclature

(Will do more research into ammines come February.) Premise Ammonia is spelled with two 'm's. The more natural derivative of the word in a linguistic sense would also have the same number 'm's. Thus ...
Linear Christmas's user avatar
18 votes
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Why are low spin tetrahedral complexes so rare?

Hybridisation won't explain anything in transition metal complexes, so please stop using it, at least to the extent where it is possible to avoid using it. Quite literally everything about transition ...
orthocresol's user avatar
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17 votes
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How to name Hg[Co(SCN)4]?

TL;DR: There is no inner- or outer coordination spheres in this complex. Both cobalt(II) and mercury(II) have nearly ideal tetrahedral coordination environment with $4$ $\ce{N}$ and $4$ $\ce{S}$ atoms,...
andselisk's user avatar
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16 votes

Why is anhydrous copper(II) sulfate white while the pentahydrate is blue, even though both have one unpaired electron?

Let's compare the two compounds, here I plotted the $\ce{Cu(II)}$ centers of $\ce{CuSO4.5H2O}$ and $\ce{CuSO4}$ from their crystal structure data. As you can see, it changes from a $\ce{[Cu(H2O)4[SO4]...
Justanotherchemist's user avatar
16 votes

Why is Ni[(PPh₃)₂Cl₂] tetrahedral?

We sometimes call this type of complex 'pseudotetrahedral' since there is an isomerism from a tetrahedral to a square planar complex possible. I was unable to find the original work here but this link ...
Justanotherchemist's user avatar
16 votes
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How does potassium hexfluoronickelate(IV) exist in a stable state?

To quote from the comments: you can get things into an amazing variety of oxidation state given the right environment. In the case of maximal oxidation states, particularly above $+2$ or $+3$ in the $...
Oscar Lanzi's user avatar
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15 votes
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How can the hybridisation schemes of transition metal complexes be determined?

Firstly, note that hybridisation theory as applied to transition metal complexes is an incorrect, flawed theory. It is an attempt to rationalise experimental observation (e.g. geometries), but in the ...
orthocresol's user avatar
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15 votes
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How can AuCl3 exist?

Gold(III) chloride does not exist as $\ce{AuCl3}$. According to Wikipedia, the name gold trichloride is a simplification of the name, which is referring to the empirical formula, $\ce{AuCl3}$. The X-...
Mathew Mahindaratne's user avatar
14 votes

Can an atom bond with more than 8 other atoms?

In october 2015, 5 months after all the current answers were given, a new cluster compound witn C.N. 16, $\ce{CoB16-}$, has been reported [1]: Here we report the observation of a large metal-doped ...
andselisk's user avatar
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14 votes
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18 Electron Rule For Determining the Stability of Transition Metal Complexes

A brief description of the 18 electron rule A valence shell of a transition metal contains the following: 1 $s$ orbital, 3 $p$ orbitals and 5 $d$ orbitals; 9 orbitals that can collectively ...
getafix's user avatar
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14 votes
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Where does the label ‘Dq’ to denote the field split in coordination compounds come from?

I currently happen to have the book by Figgis that Max mentioned. Chapter 2 is devoted to a mathematical formulation of crystal field theory, which I did not bother reading in detail because I do not ...
orthocresol's user avatar
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13 votes

Why is the magnesium(II) ion preferred over other ions in chlorophyll?

Chlorophyll in plants has two main functions. First, it facilitates energy transfer of an absorbed photon's energy via the many other chlorophylls that constitute the antenna pigment-protein complex ...
porphyrin's user avatar
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13 votes

Where does the label ‘Dq’ to denote the field split in coordination compounds come from?

A more high-level answer this time. In this approach we first find out the form of the term in the potential that will split the $d$ orbitals. Recall that the character of a proper rotation by angle $\...
user5713492's user avatar
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13 votes
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How do I find the ground state term symbol for transition metal complexes?

To find the ground state term symbol, you should be using symmetry and group theory arguments, you shouldn't have to resort to searching Tanabe-Sugano diagrams to get the answer. We'll start with ...
orthocresol's user avatar
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13 votes
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Will the bond order of CO be greater in its existence as carbon monoxide or in metal carbonyl?

In figure 1 you can see the molecular orbital scheme of a $\ce{[ML6]}$ complex including σ and π interactions. The class of ligands is not important; however, care should be taken when ...
Jan's user avatar
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13 votes
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Derivation of the Orgel diagram for octahedral d2 complexes

1. Weak-field and strong-field limits I will adopt the description used in Figgis and Hitchman's Ligand Field Theory and Its Applications (p 5), because I cannot really phrase it better: It is ...
orthocresol's user avatar
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13 votes

Proper common notation for a ligand

The ACS Style Guide suggests using $\ce{L}$ [1, p. 186] in APPENDIX 10-2 Abbreviations, Acronyms, and Symbols: \begin{array}{ll} [\ldots] & \\ \small{L} & \text{absolute configuration} \\ \...
andselisk's user avatar
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13 votes

Why is Ni[(PPh₃)₂Cl₂] tetrahedral?

Dichlorobis(triphenylphosphine)nickel(II), or $\ce{NiCl2[P(C6H5)3]2}$ in square planar form is red and diamagnetic. The blue form is paramagnetic and features tetrahedral Ni(II) centers. Both ...
Chakravarthy Kalyan's user avatar
13 votes

How is the bonding in the [Au6C(PPh3)6]2+ cluster explained?

This is by no means a trivial case. You are dealing with a so-called template or interstitial atom placement within a cluster shell. There is a thorough review available [1, pp. 18–20] (reference ...
andselisk's user avatar
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12 votes

Do ligands with a positive charge exist?

In addition to already mentioned cationic onium ligands, there is hydrazinium $\ce{H2N-NH3+}$ and its derivatives [1 -- 3]. Crystal structure of hydrazinium-trichloro-copper(II) $\ce{Cu(N2H5)Cl3}$ [...
andselisk's user avatar
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12 votes
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What is the reason of the color difference for the cis/trans isomers of tetraamminedichloridocobalt(III) chloride?

If you search a library for a copy of Inorganic Chemistry by Miessler and Tarr, they have an excellent diagram showing which explains the phenomenon. $\ce{Cl-}$ ligands have lone electrons that can ...
Xahoc's user avatar
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12 votes
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The number of geometrical isomers of complex of type [Ma₃b₂c]

First, let's establish that we're all talking about octahedral complexes to eliminate any possible confusion. Fix $\ce{c}$. You can have either $\ce{b}$ trans or $\ce{a}$ trans. If $\ce{b}$ is trans ...
Zhe's user avatar
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