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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Are the lone pairs in water equivalent?

It sounds like a dumb question based on the way we draw water, but supposedly water is $sp^3$ hybridized, so one of those lone pairs should be in an $sp^3$ orbital and the other should be in a pure p ...
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Are there any strategies to determine bond order and hybridization rankings without drawing the Lewis Structure?

I'm not Chemist. I'm taking a chemistry class in college, and the test review contains many questions where I'm asked to rank from least to greatest based on bond order, polarity, and bond angles. I ...
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What is hybridisation of XeF6 in solid state?

According to the following formula: Type of hybridisation/steric no. = (no. of sigma bonds + no. of lone pairs) it should be sp3d3, however according to my textbook it is sp3d2 in solid state. That ...
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Shape of Allene Molecule

Allene, $\ce{H2C=C=CH2}$, has two $\ce{=CH2}$ groups perpendicular to each other. This is the same as hydrogen peroxide's $\ce{H}$ atoms. Is there any reason why they adopt the perpendicular ...
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Hybridization in Oxygen and Nitrogen

What is the proper orbital hybridization O and N in $\ce{H_2O}$ and $\ce{NH_3}$? The rules say that they are sp and sp2 hybridized, respectively, but some sources say both are sp3. I have problems ...
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Why is hydrogen peroxide non-planar? [duplicate]

I had my exam this week and one question asked whether $\ce{H2O2}$ was planar or not. I though that since the oxygen atoms are both sp³ hybridized and have two lone pairs each, the molecule should ...
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Which species occupy the equatorial positions in VSEPR's trigonal bipyramidal and octahedral geometry

Which species (electronegative, double and triple bonded atoms, ions, lone pair etc.) occupy the equitorial position in the trigonal bipyramidal and octahedral geometry when we find the shape using ...
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why do we call lone *pairs*?

According to VSEPR theory molecules adjust their shape to minimize the effect of repulsion. suppose i take the structure of $ClF_3$ i has 3 bond pairs and two lone pairs. So to minimize the repulsion ...
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In PCl2F3, why are two Cl atoms not on axial position? [duplicate]

According to these sites: Chemistry Help Molbase in $\ce{PCl2F3}$, both $\ce{Cl}$ and one $\ce{F}$ atom are on equatorial position, and other 2 $\ce{F}$ atoms are on axial position as follows: ...
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Relation between various bond angles of Nitrogen compounds

I was thinking what could be order of bond angles of NH3, NF3, N(CH3)3 and N(C2H5)3. Considering NF3 and NH3: Since there is backbonding between 2p-2p orbitals of N and F, there will be a partial ...
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why do electron pairs not take axial positions in the VSEPR structure of ClF3? [duplicate]

when we make a Valence shell electron pair repulsion theory based structure for an molecule after calculating its hybridisation ; when we have to decide the positions of the ions we put them in such ...
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Can Carbon Form bonds without Hybridization?

Carbon has two electrons in its p orbital which should be able to form bonds, are there any examples in which this occurs instead of carbon hybridizing before bonding?
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Estimation of the bond angle of water

We know from experimental data that $\ce{H-O-H}$ bond angle in water is approximately 104.5 degrees. If its two lone pairs were bonds (which is unfortunately impossible) also $\ce{O-H}$ bonds and a ...
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Geometries of 4-coordinate d8 transition metal complexes

The molecule $\ce{[PdCl4]^2-}$ is diamagnetic. Since $\ce{Pd^2+}$ is a $\mathrm{d^8}$ ion, there should be two lone pairs around $\ce{Pd}$. The molecule would therefore belong to the $\ce{AX4E2}$ ...
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Why is the bond angle of AB3E1 approximately 109.5?

Since there are 3 B atoms and the angle between each atom is equal, shouldn't the bond angle be equal to 120?
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Trigonal bipyramidal arrangement with 2 lone pairs [duplicate]

So basically according to university textbooks, it is said that the second lone pair in a trigonal bypyramidal arrangement would also reside on the trigonal plane, causing the two lone pairs to be ...
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Bond angles in sulfate

My chemical bonding professor says that the $\ce{O-S-O}$ bond angles in $\ce{SO4^2-}$ are ideal (109.5°). Why? Is this because all bonds are equivalent, and electron distribution is shared among all ...
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Geometry of AsF5

Which of the following is the best description of the arragement of fluorine atoms around the arsenic atom in a molecule of AsF$_5$? (a) trigonal bipyramid (b) octahedron (c) tetrahedron (d) ...
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Why the bond angle of PH3 is lesser that that of PF3?

We can explain why the bond angle of $\ce{NF3}$ (102°29') is lesser than $\ce{NH3}$ (107°48') by the VSEPR theory, since lone pair lone pair repulsion is greater than lone pair bond pair repulsion. ...
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Why does SO2 have a larger bond angle than H2O, H2S, and NH3

So we have to find which of the follwing compounds has the smallest bond angle: $\ce{H2O}$, $\ce{H2S}$, $\ce{NH3}$, $\ce{SO2}$. So L $\propto \frac{1}{BA}$ where $L$ is the number of lone pairs and $...
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Identifying the number of bonding and lone pairs without a dot and cross diagram

I've just learned how to predict the shapes of molecules in class today using VSEPR theory. I would like to ask is there anyway to find the number of bond pairs and lone pairs without drawing a dot-...
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Question about stability of two structures of chlorine trifluoride

Why is the first structure on the left more stable than the second one on the right? In the first one the angle between the two pair of nonbonding electrons is about 120° which is a lot less than ...
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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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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 hexafluoride 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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What's the H-C-H bond angle in ethene?

The carbon is $\mathrm{sp^2}$ hybridised and is therefore planar and should also, theoretically be $120^\circ$. However, VSEPR theory suggests that the π bond would "need more space" due to ...
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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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Explaning Cis & trans isomers through VSEPR

Total rewrite as was a panic-stricken 2am question. Unfortunately I wrote on an application that VSEPR theory is a reason of Cis-Trans isomerism (specifically in fatty acids however I doubt that ...
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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 $\ce{...
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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 $\ce{IF7}...
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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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Iodate ion (IO3-). Is it polar or non-polar?

I am trying to figure out the shape of the iodate ion or $\ce{IO3^-}$. No matter how many times I draw it, I keep getting Iodine in the centre, and 3 oxygen atoms surrounding it, 2 with single bonds, ...