77
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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{...
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52
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Why do compounds like SF6 and SF4 exist but SH6 and SH4 don't?
TL;DR Fluorine is electronegative and can support the extra negative charge that is dispersed on the six X atoms in $\ce{SX6}$, whereas hydrogen cannot.
First, let's debunk a commonly taught myth, ...
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46
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Are the lone pairs in water equivalent?
Water, as simple as it might appear, has quite a few extraordinary things to offer. Most does not seem to be as it appears.
Before diving deeper, a few cautionary words about hybridisation. ...
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21
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Does nitrogen inversion affect the basicity of amines?
Background
Amine basicity correlates with, among other things, the hybridization of the nitrogen orbital that is holding the lone pair of electrons. The less s-character in this orbital, the more ...
- 84.2k
20
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Why does bond angle decrease in the order H2O, H2S, H2Se?
The question asks why water has a larger angle than other hydrides of the form $\ce{XH2}$ in particular $\ce{H2S}$ and $\ce{H2Se}$. There have been other similar questions, so an attempt at a general ...
- 30k
20
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Hybridization of nitrogen in trisilylamine, (SiH3)3N?
Ordinarily and according to Bent’s rule, we would expect nitrogen’s lone pair to be in an $\mathrm s$ orbital and nitrogen using its three $\mathrm p$ orbitals to form three bonds to the three silicon ...
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20
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Hybridisation of ClO2
I actually take issue with the question (which was asked of you not by you), as I think this oversimplifies a molecule, that still isn't well understood in the first place.
That is why I find this ...
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19
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How to rationalise the planar structre of I2Cl6?
The bonding situation in the compound $\ce{(ICl3)2}$ is by far more complex than what is depicted in this book. The molecule itself has very high symmetry, i.e. $D_\mathrm{2h}$, that needs to be ...
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18
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How can the Bonding in IF7 be explained using LCAO method?
No 6-centre-10-electron bond.
The bonding situation in $\ce{IF7}$ is explained by Christe et. al. (see ssavec's answer) as a 6-centre-10-electron bond. In the article itself I found no real ...
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18
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Is the phenyl cation or ethynylium more stable?
Preamble
As trivial as this question might seem, it is not. It should certainly never be asked in at an exam level lower than basic quantum chemistry.
Any of the tempting explanation schemes will ...
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18
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What is Drago's rule? Does it really exist?
Going through what you posted, I think ‘Drago’s rule’ (which I never encountered, either at school or at university) gives good predictions but uses a largely terrible set of arguments.
For any atomic ...
- 67.3k
18
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Hybridization of nitrogen in trisilylamine, (SiH3)3N?
To test Jan's argument, I did an NBO analysis of your structure (optimized at PBE-D3/def2-SVP with NWChem 6.6 using a conformational search with MMFF94s and Avogadro as the starting point; a frequency ...
- 2,853
17
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Does s stand for sigma bond and p for pi bond?
You got it backwards.
The $\mathrm{s}$, $\mathrm{p}$, $\mathrm{d}$, $\mathrm{f}$ orbitals stand for sharp, principal, diffuse, and fundamental. Wikipedia: Electron Configuration § Notation:
The ...
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17
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Shape of sp³ hybrid orbital
Don't put too much trust in the absolute signs of wavefunction, for they all are arbitrary anyway. Look at it this way: an s orbital has one sign (*). One lobe of p orbital has the same sign, so when ...
- 31k
15
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Structure of Benzyne
Yes, but.
Yes, in the conventional low-level models, one would consider the two carbons in benzyne you mentioned as sp-hybridised. And that does mean that their orbitals seem to be pointing the wrong ...
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15
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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 ...
- 71.1k
14
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What is the hybridization of terminal fluorine atoms in molecules like boron trifluoride?
TL;DR: As a rule of thumb, terminal (heavy) atoms are almost always best described as having sp hybrid orbitals (at the most).
For more on this, I refer you to my answer on What is the hybridization ...
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14
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Predicting sigma bond overlap strengths of s-s, p-p, s-p, sp-sp etc
I think the issue might be what orbitals are being referred to. Both books could be correct if they are referring to different $\mathrm{p-p}$ overlap. For example, suppose two atoms are bonding along ...
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13
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What is the hybridisation of trifluoromethyl free radical?
Hyperconjugation between the orbital that contains the lone pair and the $\ce{C-F}$ antibonding orbital contributes to the pyramidalization of $\ce{CF3^·}$ radical:
In the planar geometry the ...
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12
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When is there hybridization and when is there no hybridization?
As Ivan already mentioned, hybridisation is not a physical phenomenon. Physically, the most accepted theory at the moment is that you have nuclei and the electrons roam freely in between them, forming ...
- 67.3k
12
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Hybridization of sulfur in sulfur dioxide
The structure of sulfur dioxide ($\ce{SO2}$) is quite complicated.
The image from socratic.org* explains it quite well, please find the $\ce{SO2}$ hybridization diagram via the Internet Archive.
As ...
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12
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Why is cyclopropane more acidic than propane
Indeed, according to the Evans $\mathrm{p}K_\mathrm{a}$ table the cyclopropane $\ce{C-H}$ bond $(\mathrm{p}K_\mathrm{a} \approx 46)$ is more acidic than the $\ce{C-H}$ bond on the central carbon in ...
- 84.2k
11
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Why are axial bonds are longer than equatorial bond in sp3d hybridized atoms?
You are asking for $\mathrm{sp^3d}$ hybridisation, but I do not know of a case where $\mathrm{sp^3d}$ hybridisation actually happens. Either it does not make sense to discuss hybridisation at all (the ...
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11
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How are the hybrid orbitals of sulfur hexafluoride shaped?
If you limit consideration to hybridization of atomic orbitals, a good reference to see is On the role of d orbitals in sulfur hexafluoride J. Am. Chem. Soc., 1986, 108 (13), pp 3586–3593.
First, it ...
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11
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How do I compare the C=C bond lengths in this cumulene?
Label the double bonds (a), (b), and (c), in correspondence with the image provided in the question. Label the carbons in the cyclopropane ring $\ce{A}$, $\ce{B}$, and $\ce{C}$, with $\ce{A}$ being ...
- 5,431
11
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Bonding in hypervalent molecules
The starting point for a discussion should be the observed structures. $\ce{SF6}$ has a regular octahedral geometry with bond lengths of 1.56 Å. Below is a depiction compared with some other compounds ...
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10
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Hybridisation of Mn in potassium permanganate
I feel a bit like a broken record: Do not use hybridisation to describe coordination compounds; it is not helpful.
However, the case of permanganate stands out as something where hybridisation is ...
- 67.3k
10
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Hybrid orbitals forming molecular orbitals
It is still LCAO-MO theory, but just dumbed down a lot. The difference is that, instead of feeding the "pure" atomic orbitals into the LCAO mechanism, you carry out an additional mathematical step in ...
- 71.1k
10
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How are the hybrid orbitals of sulfur hexafluoride shaped?
Hybridisation is determined by geometry!
This is the number one thing that you should learn from this answer. If you know the geometry of a molecule then you can work out the hybridisation of the ...
- 15.3k
10
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Why is ammonia more basic than acetonitrile
p orbitals are higher in energy than s orbitals.
sp3 orbitals with 75% p-character are therefore higher in energy than sp orbitals with 50% p-character.
This means that the lone pair in ammonia is ...
- 71.1k
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