Valence shell electron-pair repulsion (VSEPR) theory provides simple explanations for the general shapes of molecules based on repulsion of bonding pair and lone pair electron repulsions, and we developed by Sidgwick and Powell and later Gillespie and Nyholm.

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What are actually the differences between Sidgwick & Powell theory and Nyholm & Gillespie Theory?

The famous VSEPR theory was proposed by first Sidgwick & Powell. It was modified then by Nyholm & Gillespie. I was reading Inorganic Chemistry by J.D.Lee where he discusses very briefly the ...
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Bond angles for the hydrides

I noticed the fact that all the hydrides of the elements belonging to group IV has bond angle 109.5° while in group V it varies from 107.3° for $\ce{NH3}$ to 91.3° for $\ce{SbH3}$. Similarly we see in ...
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How to know which atom is the central atom in VSEPR theory?

How to find the central atom? What is the central atom in $\ce{PCl3}$ and how to find the shape using VSEPR theory?
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Why are H2O asymmetric while CO2 is not? [duplicate]

What is the reason for water molecules $\ce{H_2O}$ being asymmetric while other molecules like $\ce{CO_2}$ being completely symmetric? See the pictures below: In both case there is an ...
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Why do lone pair- lone pair have more repulsion compared to lone-bond and bond-bond pairs?

My teacher told me that lone pair and lone pair are closer together hence the repulsion is greater and they take up more space, but I do not understand? can anyone explain it to me?
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Bond length in ICl2- and ICl2+

Why is the $\ce{I-Cl}$ bond length in $\ce{ICl2-}$ (charge of -1) is longer than in $\ce{ICl2+}$ (charge of +1) ? Here are a few explanations that I have in mind. Please critique. I in $\ce{ICl2-}$ ...
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On the geometry of sp3d and sp3d3 hybridization

A molecule in which the central atom is $sp^3d^2$ hybridized ($\ce{SF_6}$), for example, aquires an octahedral shape, which can be explained by assuming that the hybrid orbitals arrange themselves to ...
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Hybridization of Na in [Na(H2O)6]+

In the complex ion $\ce{[Na(H2O)6]+}$, the sodium cation forms 6 coordinate bonds with water ligands. Typically this octahedral form is associated with $sp^3d^2$ hybridization as far as I know, but in ...
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Dichromate ion: Tetrahedral or bent?

I am currently studying about the vespr theory and I'm stuck on an ion which is dichromate (VI) ion $\ce{Cr2O7^2-}$. So this is what I am thinking about: 1) If I make the oxygen atom at the middle ...
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SF3Cl Vsepr Most stable structure

I was asked to " Use VSEPR theory to predict the most stable structure for $\ce{SF3Cl}$ and justify your answer. " I managed to interpret the structure as seesaw and with a lone pair on the ...
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Why do many hypervalant chemicals have non-constant bond angles?

According to the VSEPR model, when a molecule in formed in the shape of $\ce{AB_{x}}$, like $\ce{IF7}$, $\ce{SCl6}$, and $\ce{PCl5}$, its structure is found by reducing the repulsions between ...
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What is the highest possible expanded octet?

Often called "hypervalent", chemicals like Phosphorous Pentachloride and Sulfur Hexaflouride are possible due to the fact that their central atoms form covalent bonds with more than four other atoms, ...
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Polarity of the nitrate ion

We observe that nitrate ion has a trigonal planar geometry according to its lewis structure and the VSEPR theory. Its resonance hybrid consists of three contributing structure -three probable double ...
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What is the molecular geometry of NHF₂?

I had to draw the molecular shape for $\ce{NHF2}$ as a Trigonal Planar like this But when I check to make sure it was right, I came across a source saying NHF2-difluoroammonia--tetrahedral, ...
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What is the geometrical structure of OF₂?

Is it linear, angular, triangular or tetragonal? Well, since $\ce{O}$ has 2 electron matches of his own, I think it's tetragonal, but in wikipedia it is angular... Why? What about $\ce{CS2}$, is it ...
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How does VSEPR theory explain the formation of different bond angles in PCl₅?

We know, that in the exited state, electrons of Phosphorus could go to higher states and form $\ce{dsp^3}$ hybridization. Therefore it will create five equal energy states of electrons. But my ...
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Why is aluminium carbide bent?

The geometry of aluminium carbide is attached. Why isn't it completely linear (in accordance to VSEPR), but bent on the Al atoms?
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Whats the H-C-H bond angle in ethene?

The carbon is $sp^2$ hybridised and is therefore planar and should also, theoretically be 120$^o$. However, VSEPR theory suggests that the pi bond would "need more space" due to greater electron ...
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How can double compounds like XeO4 form tetrahedral structures despite having double bonds?

Xenon tetroxide is tetrahedral despite having double bonds. Is it something to do with $d$ orbitals? Also things like sulfur trioxide (trigonal planar with three double bonds but the sulfur is ...
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Molecular bond angles

How do bond angles vary in molecules with a lone pair and central atom of different electronegativity, but in the same period so that electronegativity matters more than orbital size? Let's assume ...
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How is the thermal stability of nitric acid related to its structure?

How is the thermal stability of nitric acid related to its planar structure? In textbooks it is written that nitric acid is unstable at room temperature and decomposes where $\ce{H2SO4}$ and ...
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Asymmetry in trigonal bipyramidal geometry

I teach an MCAT course in chemistry. I like to explain VSEPR by saying.. first, imagine arranging electron pairs around the central atom so they are maximally distant from each other, and uniformly ...
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Why is disilyne bent?

Why is disilyne $\ce{Si2H2}$ bent when the steric number of silicon is 2?
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What is the problem in predicting the structure of XeF₆ with VSEPR? [closed]

If you try to use the VSEPR model to predict the molecular geometry of $\ce{XeF6}$, you run into a problem. What is it? What could you do to resolve the difficulty in part 1? The molecule ...
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Molecular geometry, why am i getting the wrong angles?

I'm doing this homework and I got: 109.5,109.5,109.5 for D. But it says it is wrong. I don't know why. Can someone help me? Everything else I got right
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Lone Pair 'more repulsion' VSPR Theory

I've always been told in chemistry lessons that lone pairs repel more due to a greater charge density than bonding pairs. And that makes sense when steric effects are involved when bond orbitals ...
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Quantum Valence Theory Reference

At least to me, the contents of chapters 5 & 6 given here are representative of discussions on chemical bonding given in nearly all intro general & organic chem books, the statements in those ...
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Does the hybridization model gives us any further insight on Molecular Geometry?

It doesn't seem as though the hybridization model adds anything useful to the discussion of molecular geometry as predicted by the VSEPR model. It's just another way of labeling linear, trigonal ...
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Finding the number of orbitals on a central atom

In $\ce{BeCl2}$ the number of orbitals on central atom, i.e. on beryllium, are 2. In $\ce{BF3}$, the number of orbitals on central atom , i.e. on boron, are 3. Similarly in $\ce{NH3}$ there are 4, ...
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Predicting electronic geometry, observable geometry, and hybridization for any atom in a molecule

Can someone please explain the intuition around the answers to this problem: I'm finding it very confusing because it seems like you have to nitpick between two resonance structures to get the ...
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Why are sigma bonds the only ones used in determining the geometry and bond angle in VSEPR theory? Why aren't Pi bonds used?

I have read that in VSEPR theory, multiple bonds are considered or treated as single bonds when predicting the geometry of a molecule? I've read in yahoo answers that it is because only sigma bonds ...
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Molecular Imaging - Any surprises to be had?

Molecular imaging, using STM and AFM technologies, appear so far to visually prove most of what we already know about chemical structures, such as VSEPR theory. For instance, here are the ideal ...
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Tetrahedron is minimum energy conformation for atom with 4 electron domains in VSEPR theory

Background A student asked me to prove that the regular tetrahedron is the minimum energy geometry available to describe the locations of the electron domains in three dimensions – the prediction of ...
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Bent molecular geometry of water

Could you please explain how the bent molecular geometry of water is due to hydrogen bonding? I was under the impression that it was because of the lone pairs (VSEPR Theory).
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How does localized bonding theory and hybridisation work?

So I understand molecular orbitals and how to do VSEPR models, but I seem to be struggling with understanding localized bonding theory and how to do hybridizations. After drawing the initial lewis ...
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Why do single, double and triple bonds repel each other equal amounts?

I'm here to share with you something that totally confuses me, as I can't see the logic behind it, and my teacher doesn't know either. Let's take a set of bonds that's trigonal pyramidal, with a lone ...
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Shape of C₂H₂ molecule

What is the shape of the $\ce{C2H2}$ molecule? The fact that is has a triple covalent bond between the 2 carbon atoms and 2 other bonding pairs between the hydrogen and carbon atoms leads me to ...
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What is the chemical structure of H₂SO₄?

I was looking at the chemical structure of H2SO4. Intuitively, I would have expected this molecule to be square planar in a p2d2 or sp2d geometry but rather, it is shown to be in an tetrahedral ...