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Questions tagged [vsepr-theory]

For questions about the valence shell electron pair repulsion (VSEPR) theory, in topics of: estimation of bond length, bond angle, bond energy, etc.; determining hybridization of atoms, or shape and geometry of molecules; and other related topics.

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How can I determine the highest boiling point given a list of molecules? [closed]

I know that the highest boiling point has to do with which has the strongest intermolecular force. I also know that the strongest would be ionic, then hydrogen bonding, then dipole-dipole, then london ...
2
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0answers
55 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
29 views

Why does phosphine have a dipole moment and a higher boiling point than carbon tetrafluoride?

Phosphine, PH3, and carbon tetrafluoride, CF4, are small molecules of a similar size and the same mass of 88 au. CF4 has a dipole moment of 0, which is unsurprising given its tetrahedral shape. ...
3
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1answer
91 views

Influence of the neighbouring molecules in a crystal at the example of XeF4

For reasons of symmetry I (without deeper chemical knowledge) supposed, that $\ce{XeF4}$ has a shape like $\ce{CH4}$. But according to Wikipedia its crystalline structure was determined by both NMR ...
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2answers
271 views

The real structure of difluoro(dioxo)xenon (XeO2F2)

I have a problem regarding structure of difluoro(dioxo)xenon ($\ce{XeO2F2}$). I have posted a image above. my teacher is saying that the structure B is correct as there is very less repulsion in ...
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0answers
32 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 ...
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1answer
106 views

Molecular geometry of acetylene

I need to determine the molecular geometry of acetylene, for this I have performed the following procedure: First, we represent the correct Lewis structure. Remember that the Lewis structure is a ...
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1answer
56 views

Do all sigma bonds are stronger than pi bonds? [closed]

Many textbooks refer that sigma bonds are stronger than pi bonds . But each individual bond ( between different atoms) have different bond energy. So how we know for sure that every possible sigma ...
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1answer
343 views

Shape of urea molecule around N atom

I was doing a question where I was supposed to predict the shape of the urea molecule $[\ce{H2N(CO)NH2}]$ using Lewis and VSEPR. I identified that the N atoms will have a lone pair on them and so I ...
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1answer
58 views

POI is a bent molecule similar to water. How are the two molecules different it terms of bond angles and what causes this?

phosphorus oxyiodide ($\ce{POI}$) has the VSPER AXE formula of $\ce{AX2E}$ while water, $\ce{H2O}$ has the AXE code of $\ce{AX2E2}$. According to my work sheet $\ce{POI}$ should have a $120^\circ$ ...
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1answer
77 views

Is there an algorithm that takes atom coordinates and produces VSEPR geometries?

That is, you would give the coordinates of an atom, the coordinates of four (for example) other atoms, and it would return "tetrahedral" or "square planar" or whatever. I'm currently writing a ...
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468 views

Bond Angle in Diborane, B2H6

Why are the bond angles in the diborane $\ce{B2H6}$ ring much less than $\ce{109.5^o}$? Below is the structure: This source says that the boron atoms are approximately $\ce{sp^3}$ hybridized, so I ...
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1answer
1k views

Lone pair on carbon in CO2? [closed]

CO2 has sp hybridization and no lone pairs on carbon. For some reason calculation with VSEPR gave sp2 hybridization and lone pair on carbon.
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3answers
1k views

Bond angle in CH3NCO

I was doing past year papers of A levels Chemistry, when I came across this problem: I answered (A), but the correct answer is (C) according to the marking scheme. I thought it was a bent-shaped, ...
2
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2answers
282 views

VSEPR bond angles [duplicate]

My teacher gave a practice exam concerning VSEPR and bond angles and in the following diagram, he wrote the bond angle as greater than 109.5. However, I thought that the ideal angle should be 109.5 ...
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2answers
1k views

Determine the geometry of each nitrogen atom in formamidinium ion

The geometry at A seems to be straightforward: $\ce{N}$ is surrounded by $\ce{C}$ and two $\ce{H}$'s. By VSEPR, this is trigonal planar. For the geometry at B: $\ce{N}$ is surrounded by $\ce{C}$, two ...
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0answers
173 views

What's the hybridization in diphosphorus molecule?

I read that diphosphorus has 2 phosphorus atoms joined by a triple bond (ie) it has one sigma bond and 2 pi bonds with 2 lone pairs ( 1 lone pair on each atom). I'm confused about the hybridization of ...
4
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1answer
435 views

VSEPR theory, chemical bond and quantum mechanics

VSEPR theory correctly predicts the shapes of many symmetry-broken molecules such as $\ce{H2O}$ and $\ce{NH3}$. Take $\ce{NH3}$ for example. In VSEPR theory, the nitrogen atom is (approximately) at ...
2
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1answer
584 views

Draw a diagram to show the shape of Chloromethane and explain why it has this shape. [closed]

I know it has this shape, but I don't know how to explain it. Any help is appreciated, thanks.
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0answers
139 views

How many lone pairs are there in a molecule, if it has 5 electrons (unbonded) in the valence shell?

While learning the vsepr theory, I myself thought of a random compound ClF2.(I don't know if it exists). Now I know how to arrange the valence electrons in the equitorial position and all but I got a ...
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0answers
94 views

How does the phosphate ion look like? [duplicate]

I am trying to understand how a phosphate ion looks like using the VSEPR theory. The phosphorus element has an atomic number of 15, and therefore it has a electron configuration as follow by the ...
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1answer
2k views

What is a stereochemically active or inactive s orbital?

In Concise Inorganic Chemistry by JD Lee (4th edition; adapted by Sudarshan Guha), page 73 under the section 3.6 (VSEPR Theory chapter Chemical Bonding): ...according to this theory, the position ...
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1answer
2k views

VSEPR theory and hybridization in determining the shape of a molecule

Our chemistry teacher told us that both VSEPR theory (which says that the electron pairs in the valence shell of an atom arrange themselves in such a way that repulsions among them are minimized and ...
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1answer
287 views

What is the Si–N–C bond angle in silyl isothiocyanate?

In silyl isothiocyanate, supposedly, the value of the bond angle $x$ is $180^\circ$. I don't know how to figure this out. There is a lone pair on nitrogen and two sigma bonds. Shouldn't it have sp2- ...
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1answer
2k views

Valence Bond theory, VSEPR theory and predicting the shapes of the molecules

I read about the above mentioned theories then used them to predict the molecular geometry. However, I found that the shape/geometry of a molecule obtained from both the theories was same. For example,...
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1answer
3k views

Why lone pair occupies more space than bond pair? [duplicate]

I'm not a chemistry expert and merely a high school student. In my book there is a slight introduction to VSEPR theory and therein they mention that lone pair-lone pair repulsions are maximum, ...
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2answers
6k views

Are carbocations necessarily sp2 hybridized and trigonal planar?

My copy of Pearson's Organic Chemistry (7e), Morrison and Boyd, under the section "Reaction intermediates", accords a succinct description on the structure of carbocations: The central $C$-atom (of ...
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1answer
609 views

How to explain molecular geometry without the help of VSEPR, valence bond, or hybridization theories?

I was taught, at the high school level, how to rationalise molecular geometries with the help of VSEPR, valence bond, and hybridization theories. However, I have recently also come to know that these ...
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1answer
1k views

Polarity of xenon fluoride

The structure of xenon fluoride is a capped octahedron. The lone pair is stereochemically active, i.e. it will rotate about. The dipole moments of the axial fluorides will get cancelled, and so will ...
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2answers
2k views

VSEPR Theory and Predicting Shapes of N2F2

I had asked a question on a IA Past Paper: Predict the structure of $\ce{N2F2}$ using VSEPR Theory. Now I'm not that strong at VSEPR theory. For the most part, I understand it when it involves a ...
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0answers
532 views

Geometries of SCl2(OCH3)2 and SF2(OCH3)2

I am not able to understand the difference between structure of $\ce{SCl_{2}(OCH_{3})_{2}}$ and $\ce{SF_{2}(OCH_{3})_{2}}$. I am already well versed with Molecular Orbital and VSEPR theories. I found ...
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2answers
3k views

What is the molecular shape of Sulfur Pentafluoride Anion?

$\ce{SF6}$ is an octahedral shape which makes perfect sense. $\ce{SF5^+}$ arranges 5 pairs of electrons in a trigonal bipyramidal structure. But what if you add a lone pair to this? Will the electron ...
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1answer
781 views

Why doesn't fluoride ion have highest nucleophilic power (nucleophilicity)?

As you can see from the image above, '$\ce{R3C}$' anion has 1 lone pair '$\ce{R2N}$' anion has 2 lone pairs $\ce{RO}$ anion has 3 lone pairs $\ce{F}$ anion has 4 lone pairs According to VSEPR theory,...
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0answers
111 views

Cl-A-Cl bond angle discrepancy

In 2,2-dichloropropane the Cl–C–Cl angle (108.3°) is less than the C–C–C angle (113.0°). In Me$_2$TiCl$_2$, in contrast, the Cl–Ti–Cl angle (116.7°) is larger than the C–Ti–C angle (106.2°). How is ...
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1answer
148 views

Why is the molecular geometry of a molecule with 5 bonds not uniform? [duplicate]

I'll note that I'm a student in a rather introductory course, and today we learned about molecular geometries. I'm curious as to why certain geometries (say, $\ce{CH4}$, tetrahedral) are uniform (...
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1answer
697 views

Is orbital hybridisation real?

Is the concept of orbital hybridisation an accurate description of a physical process that actually occurs in bonding atoms, or is it, like VSEPR, a heuristic tool to reason about the characteristics ...
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1answer
659 views

Is the VSEPR theory correct in determining the bond angle of sulfur dioxide?

Recently when we were doing the VSEPR Theory in class and discussing the bond angles in various compounds. That's when I thought of sulfur dioxide whose structure can be like this: According to the ...
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3answers
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4answers
8k views

Why does NF3 have a smaller bond angle than NH3?

I've already read many answers about the reason why $\ce{NF3}$ has a smaller bond angle than $\ce{NH3}$ , but I can't seem to understand them. Here's my understanding of the situation: $\ce{NH3}$: ...
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2answers
366 views

How can I derive whether the methyl cation or anion is planar?

According to VSEPR theory, in which species do all the atoms lie in the same plane? $\ce{CH3+}$ $\ce{CH3-}$ (A) 1 only (B) 2 only (C) both 1 and 2 (D) neither 1 nor 2 My try: ...
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2answers
4k views

Why is the H-C-H bond angle in CH3Cl larger than 109.5?

Symmetrical tetrahedral molecules (like $\ce{CH4}$) have a bond angle of $109.5$. Those with lone pairs in place of one atom (like $\ce{NH3}$) have bond angles less than $109.5$. The standard ...
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1answer
1k views

If a molecule has both polar and ionic bonds in it, is it polar or nonpolar overall?

To be more specific, lets take a look at the Lewis Structure of two such examples: The first one is SiCl${_3}$F. The red arrow represents an ionic bond while the blue is a polar covalent bond. ...
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1answer
2k views

Bond angles of OCl2 and OBr2

I have looked around and most of the sites suggest that bond angle of $\ce{OBr2}$ is greater than $\ce{OCl2}$ and it is explained by stating the electronegativity difference and looking at electron ...
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2answers
37k views

How do I identify Lone pair and bond pairs in molecules?

How do I identify the lone and bonding pairs in $\ce{BeCl2}$?
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1answer
119 views

Help regarding stereochemically inactive s orbital [duplicate]

Author JD Lee says in his book, Inorganic Chemistry The dipole moment of $\ce{XeF6}$ is approximately = $0$ because the lone pair is present in the stereochemically inactive s orbital. What is ...
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0answers
40 views

where will be highly electronegetive atom placed? [duplicate]

consider a molecule PCl3F2 here F is more electronegetive than Cl, which of them should occupy axial position??when i searched on internet i found these two images , they increased my confusion ...
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1answer
6k views

Why H2O2's molecular geometry is what it is…? [duplicate]

I came up with this question when I was trying to determine whether H2O2 is polar or not. H2O2 looks like this when looked parallel to oxygen-oxygen bound:(source: Pubchem) Each hydrogen is in one ...
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0answers
50 views

Why do some molecules form T shapes instead of trigonal planar shapes [duplicate]

Consider a molecule such as $\ce{ClF_3}$. Shouldn't the electron clouds (which are more negative than the Chlorine atom) want to repel each other and so the $\ce{ClF_3}$molecule should arrange into a ...
38
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2answers
3k views

Are the lone pairs in water equivalent?

I've read that the oxygen atom in water is $\mathrm{sp^2}$ hybridized, such that one of the oxygen lone pairs should be in an $\mathrm{sp^2}$ orbital and the other should be in a pure p atomic orbital....
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1answer
194 views

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 ...