Stack Exchange Network

Stack Exchange network consists of 174 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers.

Visit Stack Exchange
Join us in building a kind, collaborative learning community via our updated Code of Conduct.

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.

0
votes
0answers
37 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 ...
1
vote
1answer
274 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.
-1
votes
3answers
210 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
votes
2answers
115 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 ...
6
votes
2answers
624 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 ...
2
votes
0answers
78 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
votes
1answer
246 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
votes
1answer
199 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.
0
votes
0answers
69 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 ...
2
votes
0answers
81 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 ...
8
votes
1answer
1k 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 ...
0
votes
1answer
1k 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 ...
1
vote
1answer
174 views

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

Supposedly, the value of the bond angle $x$ is 180°. I don't know how to figure this out. There is a lone pair on nitrogen and two sigma bonds. Shouldn't it be $\mathrm{sp^3}$ hybridised?
2
votes
1answer
1k 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,...
0
votes
1answer
2k 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, ...
11
votes
2answers
3k 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 ...
7
votes
1answer
471 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 ...
1
vote
1answer
709 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 ...
-1
votes
1answer
1k views

VSEPR Theory and Predicting Shapes of N2F2

I had asked a question on a IA Past Paper. The question was: "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 ...
4
votes
0answers
351 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 ...
5
votes
2answers
998 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 ...
-1
votes
1answer
396 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,...
1
vote
0answers
72 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 ...
1
vote
1answer
84 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 (...
2
votes
1answer
466 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 ...
0
votes
1answer
401 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 ...
1
vote
3answers
2k views
4
votes
4answers
5k 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: $\ce{NH3}$: ...
0
votes
2answers
200 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: ...
7
votes
1answer
3k 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 ...
0
votes
1answer
578 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. ...
6
votes
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 ...
-2
votes
2answers
27k views

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

How do I identify the lone and bonding pairs in $\ce{BeCl2}$?
-1
votes
1answer
108 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 ...
0
votes
0answers
31 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 ...
1
vote
1answer
5k 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 ...
5
votes
0answers
47 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 ...
36
votes
2answers
2k 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....
0
votes
1answer
181 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 ...
3
votes
2answers
6k views

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 $\ce{sp^3d^3}$, however according to my textbook it is $\ce{sp^3d^2}$ in ...
8
votes
1answer
2k views

Why are the two CH2 groups in allene perpendicular to each other?

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 ...
-1
votes
1answer
787 views

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 ...
0
votes
1answer
3k views

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 ...
2
votes
1answer
825 views

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 ...
0
votes
1answer
143 views

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 $\ce{ClF3}$. It has three bond pairs and two lone pairs. So to minimize ...
3
votes
0answers
93 views

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: The ...
1
vote
1answer
584 views

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 ...
5
votes
1answer
5k views

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 ...
2
votes
2answers
1k views

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?
7
votes
2answers
555 views

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 ...