Questions tagged [isomers]
Compounds that have identical molecular formula but different chemical structure.
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Number of Isomers in this Square Planar Metal Complex (Does arrangement in square planar matters)?
I tried to work this out:
I understood that $NO_2$ and SCN are ambidentate ligands and they can be attached differently which was what I tried. I only could find and draw out 8 isomers, but there are ...
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Isomers of Pentaaminechlorocobalt(III) chloride
What kind of isomers does $\ce{[Co(NH3)5Cl]Cl2}$ exhibit?
I can rule out geometrical and optical due to there being $\ce{5 NH3}$ ligands which central metal atom cannot have different positions of $\...
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Why is the 'cis-1,3-dimethylcyclobutane' conformation of both methyl groups at the bottom more unstable than both at the top?
I'm having trouble understanding why both methyl groups on top of the ring is a more stable conformation than both at the bottom of the ring.
I found a reasoning that says the steric strain between ...
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Are conformational isomers diasteromers?
I am currently struggling on seeing where exactly conformational isomers fit within stereochemistry & how (and whether) they are a subset of diasteromers. I've seen potentially conflicting ...
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Is neo-octane possible and if yes, what is its structure? [closed]
I know iso-octane is an exception and is 2,2,4-Trimethylpentane which intuitively contains both iso and Neo groups. But then what is the structure of neo-octane or even is it possible?
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To what extent should a question such as: "how many enantiomers are there?" take geometric isomerism into account?
Pretty simple question here.
How many enantiomers are there for the structure $\ce{CH3CH=CHCH(CH3)CH2CH3}$?
On the one hand, there is just one chiral centre so one would suggest $2$. On the other ...
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Converting Quartz data from one (P3221) space group to another (P3121)
For my studies, I’ve done a lot of work on coal fly ash QXRD QPA on TOPAS which has been a fun and interesting challenge. Apart from theory reviewing, a lot of my learning so far has come from a prior ...
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Counting total number of stereoisomers of 1,2-dibromo-3,4-dimethylcyclobutane [closed]
I came across this question in one of my tests.
The answer assumes the major product (the anti markovnikov one) being formed. That is, I wish to determine number of stereoisomers of 1,2-dibromo-3,4-...
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Separating alkane/alkene isomers on the GC but the isomers have the same retention time
I'm trying to differentiate between n-octane, 3-octene, and 4-octene from a mixed sample using gas chromatography, but n-octane and 3-octene seem to have the same signal and 4-octene is shouldering ...
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How many E/Z isomers are possible for vitamin A?
If E/Z is a type of stereoisomerism, then you should be able to use the formula $2^n,$ where $n$ is the number of stereogenic centres. How is it that there are 16 possible E/Z isomers according to the ...
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Assigning configuration of chiral plane - selecting of the pilot atom
I am little confused about when it comes to assigning configuration of planarly chiral cyclophanes - and I think it comes down to selection of pilot atom.
All sources I have came across say that the ...
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Why are these structural formulas not isomers of C5H12? [closed]
A Biology textbook question stated that there are three isomers of C5H12, the structural formula of the first two isomers pentane and 2-methylbutane were pictured, the reader was then asked to draw ...
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How does phenol show tautomerism?
I read that atleast one alpha carbon has to be sp3 wrt the functional group (and has to have atleast 1 alpha Hydrogen atom) for it to show tautomerism.
I am able to see that in the keto isomers of ...
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Difficulty in E-Z nomenclature and counting number of geometrical isomers
I have found above four molecules as the geometrical isomers just by drawing them and checking if they are superimposable. I'm not sure that these are the only ones.
I have tried using E and Z but ...
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What kind of isomers are ethyl butanoate and propyl propanoate?
Are ethyl butanoate (1) and propyl propanoate (2) metamers or functional group isomers? My book claims they are metamers, but here one group is $\ce{-CO-OR}$ and another is $\ce{-CO-OR'}$ where $\ce{R}...
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Why does 2,3 dichlorobutane have 2, and not 3, stereoisomers
I understand how and that the R,S and R,R stereoisomers are different.
But I don’t see why the R,R and S,S compounds are stereoisomers and not meso compounds with each other.
Online it says that ...
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Is eta hexachloro cyclohexane optically active compound?
Quoting from Wikipedia,
Hexachlorocyclohexane (HCH), $\ce{C6H6Cl6}$, is any of several polyhalogenated organic compounds consisting of a six-carbon ring with one chlorine and one hydrogen attached to ...
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Reactivity of 1-bromo-4-tert-butylcyclohexane isomers with methanol
(1s,4s)-1-bromo-4-tert-butylcyclohexane (1) and (1r,4r)-1-bromo-4-tert-butylcyclohexane (2) are heated (E2) with $\ce{NaOCH3}/\ce{CH3OH}.$ Which isomer will react faster?
What will change when $\ce{...
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Why does 1-ethylidene-2,3-dimethylcyclopropane exhibit cis-trans isomerism?
I think the carbons 2 and 3 have different configuration according to the CIP rules which makes the groups different:
Am I correct? Is there any official criteria regarding these cases ?
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How does the size of a molecule subject to photo-isomerization affect it's isometric configuration?
When azobenzene is photo-excited to a higher energy configuration, the electron orbital take new energy levels and position's, changing the over all configuration of the molecule.
Now, if various ...
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Number of stereoisomers of 1,3,5-trimethylcyclohexane
When I searched the stereoisomers of 1,3,5-trimethylcyclohexane, I got four structures given below.
I don't get how structures 1 and 2, 3, and 4 are not the same. Could anyone explain?
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How can I find all possible isomers of a given molecule?
I attend a course on combinatorics (mathematics) which contains many examples related to chemistry. Unfortunately, I don't have enough chemistry knowledge to feel comfortable with the examples.
For ...
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Do ketdione molecules have diol tautomers?
In my chemistry textbook there's a keto-enol tautomerism example:
But will it also be in equilibrium with pent-1,3-dien-2,4-diol in a reaction like this or will it just be a functional isomer?
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Why this structure is diastereomers instead of enantiomers
In this diagram optical isomers has divided in to 2 categories, one is diastereomers and enantiomers. Is the example for diastereomers correct? For me its looks like enantiomers
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Why doesn't 2,3-pentadiene show geometrical/cis-trans isomerism?
There are two different groups bonded to each terminal C in the C=C=C system, and there is restricted rotation about the C=C=C. So why doesn't it show cis-trans isomerism?
The most common answer I get ...
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Why is the formation of the nitro isomer more favorable under acidic conditions
In the reaction between chloropenataamminecobalt and nitrite either the NO2 or the ONO linkage isomer is formed. This preference seems to be mainly due to the pH of the solution with acidic conditions ...
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Why total stereoisomers is 1 even if no geometrical isomers and optical-isomers are present [closed]
Let's for example take the complex structure type $\ce{MA_6}$, What will be the Total number of Stereo-isomers (=[Geometrical-isomers]+[optical-isomers]).
My effort was that There will be no G.I and ...
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How many geometrical isomers will be formed here?
Can someone help me calculate the number of geometrical isomers in this compound? According to me there should be 3 isomers here but according to my teacher, there are 4.I believe that both EZ and ZE ...
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Total number of Isomers of [Co(NH3)5(NO2)](NO3)2 [closed]
I encountered this question in my country's Chemistry textbook of class 12. No solutions are published, but the answer given at the back states - "There are 10 possible isomers. (Hint: There are ...
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Does solvate isomers exist for coordination compounds with ammonia solvent as ligand?
I could find many sources confirming the hydrate isomerism(with water as solvent) but I couldn't find any information about any other solvent. In all the sources "hydrate/solvate isomerism" ...
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Number of enol forms of acetylacetone
Here is what I tried:
These are the two enolic forms that I could make. So according to me, the total number of distinct enol forms of acetylacetone is $2$. But the answer is 3, what am I missing?
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What is the error in the number of aromatic isomers of C7H8O?
I am a student studying basic organic chemistry (isomerism) and was asked a question to find the number of aromatic isomers of $\ce{C7H8O}$.In fact this was a question in IITJEE exam. So I tried to ...
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The total number of stereoisomers of 1,2-dibromo-3,4-dichlorocyclobutane
I tried writing all the geometrical isomers for 1,2-dibromo-3,4-dichlorocyclobutane, and then saw if they were optical or not. And I am getting the answer as 10:
However, the given answer is 8. I can'...
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Confusion in D/L nomenclature [duplicate]
With regard to carbohydrates, it is known that in a Fischer projection, if the $-OH$ group is on the right side of the lowest priority asymmetrical (chiral) carbon, then we name it as D and if it is ...
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Chirality of conformations of butane
I have read that the conformations of butane are as follows:
I came across a question about number of chiral conformations of butane.
My Attempt :
The total or fully eclipsed is achiral because it ...
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Tautomerism between cyclohex-2-en-1-one and cyclohex-3-en-1-one
I think cyclohex-2-en-1-one and cyclohex-3-en-1-one should undergo tautomerism as shown below:
I'm calling it tautomerism because of it's similarity with the tautomerism mechanism in basic medium. I ...
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Confusion in R/S Nomenclature and Chirality [closed]
I have many confusions regarding optical isomerism:
What is the use of the R/S nomenclature? I understand that it is used to distinguish between the different spacial arrangements that are possible ...
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How do molecules with opposite rotational photoisomerization bonds behave? [closed]
If a molecules bond change upon isomerization with the respective bonds straining the molecules as they orient themselves opposite from each other, would the molecule undergo some kind of ...
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Why is [M(AB)2] a geometrical isomer?
Our teacher told us that for coordination number 4 and tetrahedral shape $\ce{[M(AB)2]}$ doesn't have a plane of symmetry, so it shows optical isomerism.
What if we take a plane passing through the ...
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What is the isomeric relation between bicyclo and spiro hydrocarbons?
Take for example octahydropentalene (bicyclo[3,3,0]octane) and spiro(3.4)octane:
I would think that they are chain isomers of sort but according to nomenclature counting rules, they are both 8-carbon ...
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Isomerisation Reactions of Alkyl Halides
My organic chemistry textbook says:
Haloalkanes on heating at 573K or in presence of anhydrous at low temperature undergo molecular rearrangement to form an isomeric haloalkane.
I noticed a ...
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Do ambident nucleophiles form functional isomers?
I came across cyanide and isocyanide in an example for functional isomerism. As they are also ambident nuclephiles, I wanted to know if other ambident nucleophiles would also exhibit functional ...
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Does this molecule show cis-trans isomerism? [duplicate]
I want to find if the above molecule shows cis-trans isomerism, per an assignment. I am assuming that such isomerism, if present, will be shown by the substituted chlorines.
It seems clear to me that ...
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How does optical activity work? [duplicate]
I have learnt that chiral molecules are able to show optical activity; that is, they are able to rotate plane polarized light by some angle.
But how does it actually happen? Won't the orientation of ...
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Stereoisomers of 1,3,4,6-tetramethylcyclohex-1,4-diene
How many stereoisomers are possible for following compound (1,3,4,6-tetramethylcyclohex-1,4-diene)?
My Approach
the 1,4 methyl groups lie in the plane, whereas 3,6 are possible chiral centers. ...
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Keto-enol tautomerism in a bicyclo compound
Question
Which one is more stable- the keto or enol form. The compound given is this:
Solution
The enol form would violate Bredt's Rule and would therefore be unstable. Hence the keto form is more ...
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Assigning E–Z configuration for alkenes with cyclic substituent groups [duplicate]
I was taught that according to CIP rules, we must check the priority order for the substituents. But how can we do the same for molecules with cyclic groups as substituents?
How do we compare the ...
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Properties of stilbene isomers
(E)-stilbene may be separated by crystallization from (Z)-stilbene and the side product of the Wittig reaction, triphenylphospine oxide (TPPO), by using absolute ethanol. My question is why? (E)-...
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Are (1R,2S)‐1,2‐dibromocyclopentane and (1R,3S)‐1,3‐dibromocyclopentane positional isomers?
Are these positional isomers or not? According to me they are, since Br substituent is located at different positions in both the pictures, but the answer key in one of my mock test websites says they'...
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How many stereoisomers are present in octahedral complexes of type MA3B2C?
Does $\ce{MA3B2C}$ type have optical isomerism or just geometric isomerism? I was told that it has three isomers, two cis and one trans. Are the two cis isomers optically active?
