Questions tagged [valence-bond-theory]
Questions about how the atomic orbitals of the dissociated atoms combine to give individual chemical bonds when a molecule is formed.
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But what are anti-bonding pi-orbital? In search for an intuitive explanation [closed]
Imagine that you want to explain to an undergraduate why they have to to shade the pi-orbitals in a symmetrical way, i.e. dark on top (+), white on bottom (-) for two neighbouring pi-orbitals because ...
-2
votes
1answer
40 views
Is hypervalency a real thing? [duplicate]
I saw a proper debate going on between answers to a question about whether the octet rule could be violated. Some people were pointing to hypervalency in period 3 elements, due to the available d-...
1
vote
1answer
57 views
How to determine the shape of hybridized atomic orbitals in VB theory?
From diagrams, it's rather obvious how $sp$ orbitals are hybridized - the hybrids are just a composite of the $s$ and the $\pm p_{(x)}$ orbitals. However, $sp^2$ orbitals are not just composites of $s,...
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26 views
Hybridization state of oxygen in carbonyl sulfide (COS) [duplicate]
I've been scratching my head on this one for awhile here. In a carbonyl sulfide (COS) molecule, what is the hybridization state of oxygen?
Carbonyl sulfide is composed of a single carbon atom double ...
0
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1answer
72 views
Backbonding in phosphorous pentoxide
I read this today in a book that $\ce{P=O}$ in $\ce{P4O10}$ consists of a coordinate bond and pπ-dπ backbonding, but why does this happen?
Can't phosphorus share its lone pair with one of the lone ...
0
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1answer
59 views
Why does this ligand form 6-coordinate complexes with Transition elements and 8-coordinate complexes with Inner transition elements? [closed]
What change takes place in the denticity of this ligand if it is an inner-transition metal ion vs a common transition metal?
Primarily, why does the ligand behaves differently with the two situations ...
2
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2answers
249 views
Comparing bond angles in carbonyl dichloride and carbonyl dibromide
Background
I was studying VSEPR and hybridization theory and one of the popular questions in many textbooks was comparison of bond angle of $\ce{NH3}$, $\ce{NF3}$ and $\ce{NCl3}$.
$\ce{NF3}$ had ...
6
votes
1answer
84 views
Hypervalency of orthonitrate
I have always believed that it is impossible for the atoms of period 2 elements (when they are the central atoms in polyatomic ions/molecules) to accommodate more than 8 electrons in their valence ...
2
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2answers
61 views
Effect of magnetization on oxidation (rusting) of iron
Can magenetizing a piece of iron bar slow-down (or speed-up) the oxidation (rusting) process? In other words have any influence on it ?
From what I've looked up( wikipedia, quora), it appears that the ...
2
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0answers
43 views
Can one describe the bonding of Na to F in terms of molecular orbital theory? What about valence bond theory?
I would kindly appreciate an explanation in terms of the two accepted quantum mechanical theories -valence bond & molecular orbitals- for the electronic energy level structure in natrium fluoride $...
3
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1answer
123 views
Bonding and coordination of oxygen in a Ga2O3 crystal structure [duplicate]
I'm trying to find the crystal structure of gallium oxide ($\ce{Ga2O3}$). However, I find the images of the crystal structure in the peer-reviewed journals problematic.
First, I hop to the wikipedia ...
3
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0answers
51 views
(Mis)understanding on MOT
In VBT, one can understand the example of hydrogen like this - Two hydrogen atoms come closer to each other, and their orbitals overlap, stabilize, and ultimately result in a bond. This is not too ...
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34 views
Hybridization theory (orbitals used in different hybridizations)
Why is $d_{x²-y²}$ orbital used in $sp^3d$ (square pyramidal geometry) while $d_{z^2}$ orbital in $sp^3d$ (trigonal bipyramidal geometry)?
I came across this information while reading J.D.Lee Concise ...
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0answers
31 views
Reconciling electron configuration and valence electron distribution over separate energy levels in energy band theory [duplicate]
The electron configuration of a Silicon atom in its ground state is $\ce{1s^2 2s^2 2p^2 3s^2 3p^2}$, or equivalently, $\ce{[Ne] 3s^2 3p^2}$.
When looking at the energy-level scheme of a silicon atom, ...
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0answers
86 views
Valency of each atom in a molecule with python
Consider ethanol, where each carbon atom has a valency of 4 and oxygen a valency of -2. I would like to determine these values for many compounds given their SMILES or InChI keys. (For the purpose of ...
0
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1answer
91 views
Confusion about hybridization terminology
I was just introduced to the concept of orbital hybridization. I believe I understand the idea behind it, but there is some accompanying terminology that prevents me from achieving a greater ...
1
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1answer
557 views
Magnetic nature of tetraamminedichlorocobalt(III) chloride
I know how to predict magnetic nature when the compound contains only strong field or only weak field ligands. But in $\ce{[Co(NH3)4Cl2]Cl},$ $\ce{NH3}$ is a strong ligand whereas $\ce{Cl-}$ is a weak ...
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0answers
39 views
Is bonds in CO is all 3 coordinate bonds or 2 covalent and 1 coordinate bonds?
Below image is as available in India's Class 11 NCERT Chemistry book vol 1 Page 104. I am confused as it states all 3 bonds are kind of coordinate bonds. Should it not start with 2 covalent bonds and ...
0
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1answer
259 views
Why is the valency of the Calcium (Ca) Bohr model, set to 2 electrons, instead of 1 electron for stability? [duplicate]
This is an Ascii table for the elements on the 4th period (row) of the periodic table, and distribution of electrons in each orbit.
...
0
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1answer
2k 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 ...
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0answers
154 views
Why are sulfur trioxide and nitrate not isoelectronic, even though both have the same number of outer electrons?
Though $\ce{SO3}$ has the same number of outer electrons as $\ce{NO3-}$, the two are not isoelectronic.
This statement is from JD Lee, but I could not understand why is he calling these two molecules ...
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0answers
177 views
Why do the d orbitals contract when pairing of electrons start, because the size should increase due to increase in energy
The energy of an orbital is proportional to its mean radial distance, and since the 3d orbital is much larger it is much higher in energy than the 3s and 3p orbitals
All references from JD Lee ...
1
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2answers
199 views
Bonding in the nitrate anion [duplicate]
Hi so I was studying chemical bonding where i encountered a problem which is stated below.
When we talk about ${NO_3}^-$ we draw its structure as following
But the thing which I dont understand is ...
0
votes
1answer
848 views
Bond dissociation energy among halogens [duplicate]
Among the halogens, why is it that the fluorine has the lowest bond dissociation enthalpy, considering the fact that fluorine is the smallest and the internuclear distance between the fluorine ...
0
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0answers
31 views
How one can calculate Si-O-Ca/Mg valence angle energy?
I want to perform the relaxed scan (or relaxed surface scan) for the valence angle energy of Si–O–Ca, Si–O–Mg, Al–O–Ca, and Al–O–Mg. I will use DFT (ORCA), probably B3LYP and triple zeta basis set (...
0
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0answers
43 views
Reason behind hybridisation [duplicate]
I have been taught that orbitals can overlap only when all of them are in the same energy state. That is the reason why the orbitals hybridise in a kind of 'mixing up' and give rise to orbitals having ...
4
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2answers
129 views
Is dihydrogen the only example of overlap between two s orbitals?
I heard that $\ce{H2}$ is the only example of s–s orbital overlap. Can anyone give an example which contradicts this statement?
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149 views
Why are d(xy),d(yz) and d(xz) orbitals involved in d³s hybridisation?
Shouldn't d(x²-y²) dxy and dz² orbitals participate? Since this corressponds to the best case overlap?
What factors decide the participating orbitals in hybridisation?
P.S I am well versed with the ...
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1answer
49 views
Doubt regarding timeline of events and development of theories
I recently studied Zaitsev's and Hoffman's rules for deciding which product is formed via elimination and noticed that the rules for formulated much before the discovery of electrons and any ...
2
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1answer
595 views
Why is $1s-1s$ orbital overlapping stronger than $2p_x-2p_x$ orbital overlapping?
Assume the x-axis to be the internuclear axis. Hence, both $1s-1s$ and $2p_x-2p_x$ will form $\sigma$ bonds.
Also consider the fact that $p$ orbitals have more directional characteristics.
Given the ...
2
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0answers
95 views
Why is it not possible for seven close copper atoms to come together to gain a noble-gas configuration of valence electrons?
My textbook says the following about metallic bonding:
The metal copper has one valence electron. The valence electrons of nearby copper atoms are shared in a similar way to covalently bonded ...
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0answers
117 views
How to Choose Orbitals for Hybridization
Recently, I was reviewing my textbook regarding orbital hybridization, and one of the problems was to determine the hybridization of each of the atoms in $\text{CO}_2$. I understand why the ...
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1answer
43 views
Periodic Table and Atomic Radius
Well Wikipedia says that the atomic radius is lowered for elements in a group closer to noble gases (same row). It also says that those elements want to keep their valence electrons more than metals, ...
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1answer
43 views
Electric conductivity
Well I was wondering why some materials have a higher resistivity than others . So I took two elements randomly . I picked carbon and silicon . Carbon has lower resistivity than silicon and obviously ...
6
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1answer
602 views
Valence bond theory and molecular orbital theory — how do they complement one another?
Based on my readings, valence bond theory (VBT) and molecular orbital theory (MOT) tend to complement one another in explaining a molecule, but I don’t understand how VBT helps us explain the ...
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0answers
1k views
How do I explain these bond angles in SF4 and SOF4?
From here and here I found that the bond angle between the equatorial $\ce{F}$'s in $\ce{SF4}$ is less than that in $\ce{SOF4}$. I understand that is because of greater repulsion by lone pair than by ...
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1answer
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Why does NH3 hybridize at all?
So in Chemistry class I've been taught that hybridization is a way we can explain things such as how $\ce{CH4}$, for example, forms four, equally strong bonds.
However at the same time I'm told that ...
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votes
1answer
395 views
Why is a carbon to iodine pi-bond less stable than a carbon to fluorine pi-bond?
This question comes from a second semester undergraduate organic chemistry course. Please refer to the image below with regard to the question.
My understanding of the trend in section 4a is that "...
3
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1answer
486 views
Reason for shorter bond between sulphur and oxygen?
I recently came across this sentence in my textbook:
the bonds between sulphur and oxygen in oxides of sulphur ($\ce{SO2}$ and $\ce{SO3}$) are much shorter than might be expected for a single bond.
...
2
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1answer
1k views
Why is carbon monoxide a monodentate ligand
Carbon monoxide has lone pairs on both the carbon and the oxygen atoms. However, I have never seen any complex where the oxygen atom or both the oxygen and the carbon atoms are the donors.
I know ...
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0answers
284 views
Dichlorine monoxide molecular geometry
I need to predict the geometry of Dichlorine monoxide, using the main link theory: Lewis model, VSEPR and hybridization of molecular orbitals.
First, the Lewis structure is a graphical representation ...
5
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1answer
4k views
Bonding in Zeise's salt
I am not sure I completely understand the bonding in coordination compounds formed by donation of pi electron cloud by the ligands to the central atom.
For example, consider Ziese's salt:
I came ...
-1
votes
1answer
225 views
How many equal Xe–O bond length are present in (XeO_6)-3? [closed]
I tried to solve this problem by drawing a structure but the structure did not give me any answer and I was not able to draw the proper structure please help me out.
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0answers
26 views
Why does aluminum in zeolites form tetrahedras? [closed]
It forms a bond with four oxygen atoms even though it has only there electrons in his outter shell?
0
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1answer
2k views
Graphite: Thermal and electrical conductivity
I recently encounter this question:
Compare, while providing an explanation, the thermal and electrical conductivity of graphite to that of diamond.
Provided answer:
Graphite conducts electricity(...
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0answers
230 views
The nature of Chemical Bonds [closed]
It was nearly a year ago when I appeared for my first interview through the KVPY (a research oriented scholarship exam) when one of the questions the panel asked me was :
What is a chemical bond?
I ...
4
votes
1answer
2k views
Ionization energy of C2-, C2, and C2+
My textbook says that $\ce{C_2}^-$ has a lower ionization energy than both $\ce{C_2}$ and $\ce{C_2}^+$. I calculated that the bond orders of $\ce{C_2}^+$, $\ce{C_2}$, and $\ce{C_2}^-$ are 1.5, 2, and ...
3
votes
0answers
584 views
Why is octet extra stable? [duplicate]
In chemistry, it is agreed in general that the octet is extremely stable, through experiments except in some cases. But is there any specific theoretical reasoning for that?
According to me, if:
...
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0answers
207 views
Why don't I get the same value of percentage ionic character of a particular molecule from different equations?
About the ionic character of a polar covalent compound Pauling gave two equations as
[1-$e^{.25(x_a - x_b)}] $%
[18$(x_a-x_b)^{1.4}$]%
Hanary and Smith gave the equation
[$16(x_a-x_b)+3.5(x_a-...
2
votes
1answer
68 views
Using real wave functions for chemical bond explanation
My question related with another one here.
For explanation valence bond direction chemists are used real wave functions, for example $p_x, p_y, p_z, \ldots$. But this functions do not describe the ...
