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Questions tagged [cis-trans-isomerism]

Stereoisomeric olefins, cycloalkanes, etc. which differ in the positions of groups relative to a reference plane: in the cis-isomer the atoms are on the same side, in the trans-isomer they are on opposite sides. An obsolete synonym, for which the usage is strongly discouraged, is geometric isomerism.

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Does 1-chloro-4-(chloromethylidene)cyclohexane show geometrical isomerism?

Would this compound show geometrical isomerism, or GI for short? There certainly wouldn't be any restricted rotation for any atoms in the ring, as for the chiral carbon having chlorine and hydrogen (...
Mr Gubbo's user avatar
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Geometrical isomerism in spiro structures

The following structure shows Geometrical isomerism (GI for short) because the -Cl and -Br are in same plane This structure does not show GI because the -Cl and -Br are in perpendicular planes and ...
Ninjametry's user avatar
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Are these stereoisomers considered geometrical isomers?

I came across this compound in the Black Book of Organic Chemistry by Ashish Mishra. The question asked whether this compound could show geometrical isomers. Now, I know the compound has the ...
Man's user avatar
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What is the number of different compounds formed from the monochlorination of cis-1,2-dimethyl cyclopentane?

I encountered this question in the Black Book of Organic Chemistry by Ashish Mishra while preparing for a college entrance exam. According to the answer key the answer is 12. I have only managed to ...
Man's user avatar
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4 votes
1 answer
242 views

Why is cyclooctene the smallest cycloalkene to have cis-trans isomerism?

What prevents cis and trans isomers from existing in smaller cycloalkenes, for example, cyclohexenes for more than a short period of time?
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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 ...
JERry's user avatar
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1 answer
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Why trans-dibromoethane is more favorable than cis-dibromoethane? [closed]

2 questions: Is trans-dibromoethane more stable than cis-dibromoethane because it's more symmetrical (in terms of molecular weight distribution on either side)? Is it always the case that trans ...
April Zheng's user avatar
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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 ...
FShrike's user avatar
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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 ...
Rishi Shekher's user avatar
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stable conformation of 2,3-dimethylsuccinic acid

I was researching for answering this question on Kolbe's electrolysis of 2,3-butanedicarboxylic acid (succinic acid). Turns out, this compound is not very well researched in particular, and shows few ...
ananta's user avatar
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Is hydroxylamine monodentate or ambidentate ligand?

What is the total number of geometric isomers of the complex $\ce{[Pt(Cl)(py)(NH3)(NH2OH)]+}$? If $\ce{NH2OH}$ acts as an ambidentate ligand, then there should be six geometric isomers. Or is it ...
Ritesh 's user avatar
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1 answer
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Why is the 'side' of a double bond defined across the double bond horizontally rather than vertically? [closed]

When we are determining cis-trans isomerism, we seem to refer to a molecule's 'side' in relation to the double bond in a horizontal manner, as if we had drawn a mirror line through it horizontally. ...
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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 ?
Ali's user avatar
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Comparing acidic strength of crotonic and isocrotonic acids

Compare acidic strength of crotonic acid (1) and isocrotonic acid (2): On comparing $\mathrm{p}K_\mathrm{a}$ values, cis-form $(4.44)$ turns out to be more acidic than the trans-form $(4.69)$. Most ...
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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 ...
user119212's user avatar
1 vote
1 answer
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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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5 votes
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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'...
Perseus's user avatar
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Does 1,4-dimethylcyclohexane have a chiral center?

My textbook says that 1,4-dimethylcyclohexane (cis or trans) does not have a chiral centre, since two groups on the tertiary carbon (that are the part of the ring) are identical, and thus the compound ...
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2 votes
1 answer
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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 ...
Soumil Gupta's user avatar
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2 answers
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Determining if the product would be cis or trans after an anti elimination on fischer projections

I find these kind of problems really confusing for some reason, but I saw a way on the web and tried doing it that way: I considered the basic Fischer operations (Vertical: Below the plane of paper, ...
Prajwal Tiwari's user avatar
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0 answers
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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 ...
Ray Bradbury's user avatar
7 votes
1 answer
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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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Why is Maleic Acid more soluble in water than its trans isomer Fumaric Acid?

My teacher taught me that compounds having intramolecular H-Bonding are relatively less soluble in water as they will not involve in H-Bonding with water appreciably while those able to do ...
Swapnil Kashyap's user avatar
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0 answers
435 views

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?
notsoanonperson's user avatar
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Why does hydrogenation of this compound not result in a diastereomeric mixture? [duplicate]

In a question, this compound was given and it was asked: "Hydrogenation of the above compound in the presence of poisoned Palladium catalyst gives?" When I was answering it, I thought that ...
TheLastAirbender's user avatar
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1 answer
2k views

Why these compounds don't show and show Geometrical isomerism? [closed]

I was recently studying organic chemistry related to Isomerism. I have doubt based on an example that is, Why Cumulenes show GI? Why 1-chloro cyclohexene don't show GI?
CHEMOJEE's user avatar
2 votes
1 answer
166 views

Is there geometrical isomerism in case of 2-methylcyclopentanone?

How can 2-methylcyclopentanone show geometrical isomerism? A ring and a double bond are in different planes, so even after having restricted rotation there will be no change in areal distance.
Nivedita Chowdhury's user avatar
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1 answer
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Which are the Geometrical isomers of the complex [Cr(NH3)2Cl2(en)]+?Is it one or two?

I was recently studying coordination compounds and i came across optical isomerism shown by complexes.I think that the complex i gave above have 4 geometrical isomers(I think this is where I am wrong, ...
Muhammed Rishan's user avatar
2 votes
0 answers
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Synthesis of Pt(II) complex using trans effect

By making use of the trans-effect in platinum(II) complexes, show efficient routes for the synthesis of all the possible isomers of $\ce{[PtCl(NH3)2(py)]+}$ (where $\ce{py}$ = pyridine) from the ...
Coyazayo's user avatar
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0 answers
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For a flat, planar molecule, how do you determine which side is up? Or down?

I was just reading about alpha and beta linkages in certain cyclic molecules, and it said that the alpha configuration was the one in which a hydrogen was sticking out above the plane, and an OH ...
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4 votes
1 answer
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Chiral centres with stereoisomeric substituents

The structure of one particular isomer of 4-chlorohepta-2,5-diene is shown here. I am confused about how two of the propenyl groups attached to the central carbon have the same atoms with different ...
Arun Bhardwaj's user avatar
-4 votes
1 answer
137 views

Terminologies used in isomerism [closed]

What is the difference between the terms constitutional isomers, stereoisomers, geometric isomers? I know cis and trans-1,2-dichloroethane shows cis trans isomerism and 1,1 dichloroethene, 1,1,2 ...
Saniya's user avatar
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7 votes
1 answer
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In what way trans alkenes are more symmetric than cis alkenes?

While providing the reason for the higher melting point of trans molecules, everyone says that trans molecules are more symmetric than cis molecules. An example can be found over here, where the OP ...
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3 votes
1 answer
620 views

Number of Stereoisomers of C(CHClCH3)4

I am having trouble understanding why the structure $$\ce{C(CHClMe)4}$$ has only five stereo isomers. According to my textbook, the stereo isomers correspond to the following series of absolute ...
John Tony's user avatar
19 votes
3 answers
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Can geometrical isomers be enantiomers?

I have just been pondering upon the question above. I have found this example and I am sure they are enantiomers, but do they also count as geometrical isomers?
Harsh Katara's user avatar
-2 votes
1 answer
2k views

MA3B3 isomers - is this same as meridional one? [closed]

I'm new to studying stereo chemistry. (Now I'm studying coordination complexes.) In my class material and other some datas(from google), it says that there is two, fac and mer. I want to know is ...
Woojin K's user avatar
-1 votes
2 answers
567 views

Conversion of cis to trans isomer [closed]

why in cis and trans isomers the double bond cannot be broken once and again joined to convert them from cis to trans is this type of bond breaking not allowed or is this allowed?
Kiran Thapliyal's user avatar
2 votes
0 answers
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Shortcuts for finding geometrical isomers

Our teacher provides us extra questions for pratice, so one of the questions was :- Find number of products if following are reacted with excess $\ce{NH2OH}$ (hydroxyl amine): Cyclohex - (i) 1,4-...
aryan bansal's user avatar
-1 votes
1 answer
213 views

Optical activity of cis-trans isomers of a co-ordination compound [closed]

Why do geometrical (cis and trans) isomers of [Pt(NH3)(Br)(Cl)(py)] not show optical activity ? Thanks In Advance...
user74156's user avatar
1 vote
1 answer
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Conformers of a meso-compound [duplicate]

In a particular question in one of my reference book, I was asked if the given compound (meso-butane-2,3-diol) was a meso compound or not. In it’s solution part, to show that the compound was ...
Klyen Dave's user avatar
1 vote
1 answer
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Optical activity of cis coordination compounds

I came across a statement saying, "Consider a Octahedral coordination compound of type [MA2X2]. Then, if the compound is in a cis form, it shows optical activity as there is no plane of ...
The Jade Reaper's user avatar
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2 answers
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Why are we still using cis/trans system while the E/Z system is better than it?

I am currently learning about Alkenes. It is given that cis/trans isomerism is either ambiguous or doesn't even apply in cases where the alkene is trisubstituted or tetrasubstituted. To solve this ...
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1 vote
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Do the groups involved in geometrical isomerism have to be in similar planes to show geometrical isomerism?

In my textbook, under the topic "Conditions for geometrical isomerism", the following has been given: Groups responsible to show geometrical isomerism must be nearly in the same plane. Is this ...
Vishnu's user avatar
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Will N,N‐diethylbenzamide show geometrical isomerism?

I know for a compound to show geometrical isomerism it should have site of restricted rotation; be connected to two different groups on either side of site of restricted rotation; the distance ...
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Plaster of Paris

One of my Chemistry professors said that the hard mass formed after adding water to Plaster of Paris, cannot be converted back into Plaster of Paris. However, he said that the original Gypsum can be ...
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Trans vs. cis, or Z vs. E

I am new to organic chemistry and am confused regarding the following question: Does the geometrical isomerism of 3-methyl-2-heptene fall into the category of trans vs. cis, or the category of Z vs. ...
dalta's user avatar
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1 answer
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Can there be geometrical isomerism in resonating structures [closed]

If a double bond which has two different substituents on each of it's two ends is showing resonance with one of the substituents would the double bond exhibit Geometrical isomerism?..if yes how so ...
Schwarz Kugelblitz's user avatar
2 votes
2 answers
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Does 1,3‐dichloroallene show geometrical isomerism? [duplicate]

Since the attached groups are present in different planes, $\ce{ClCH=C=CHCl}$ should not show geometrical isomerism, but my book say that it does. Why?
Abhishek Kumar's user avatar
2 votes
0 answers
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What does the dissociative mechanism for cis/trans interconversion of [Mo(CO)4(PPh3)2] look like?

All I can find in the literature is that the cis→trans interconversion proceeds via dissociation of one of the PPh3 ligands resulting in a square-pyramidal Cs intermediate, with the remaining PPh3 in ...
Funk's user avatar
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E - Z configuration of cyclic substituents [closed]

The answer is coming out as Z but given is E. I’m not sure where I’m wrong at this point as I moved along one chain at a time and wanted to follow heaviest atom as earliest as possible !
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