Questions tagged [cis-trans-isomerism]

Obsolete synonym for cis-trans isomerism. (Usage strongly discouraged).

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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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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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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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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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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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Bends in cis Isomers

It’s been said over and over in my biochemistry books that the cis-double bonds between the Cs in the hydrocarbon tails in triglycerides causes a kink. This kink disappears when the bond is isomerized ...
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The number of geometrical isomers of complex of type [Ma₃b₂c]

Find out the number of geometrical isomers of the complex $\ce{[Ma_3b_2c]}.$ I applied simple combinations to get the number of isomers as $$\frac{6!}{3!\,2!} = 60.$$ However, my book states that ...
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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, ...
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Is a carbon chiral it two of its groups are cis - trans isomers? [duplicate]

For example: In this image, the two groups sticking to a carbon are cis-trans isomers. So does that make the carbon chiral, exhibiting optical properties? What if the two groups were both having ...
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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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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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754 views

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 ...
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501 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 ...
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1answer
644 views

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 ...
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When is rotation around double bonds to form cis-trans isomers allowed?

Textbook Question: The rhodopsin molecules in the retina contain a derivative of vitamin A called cis-retinal (Figure 6). On exposure to light, cis-retinal becomes an isomer called trans-retinal. ...
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How to derive these general formulae for number of stereoisomers of a compound with a possible plane of symmetry?

These formulae are used if the molecule has a possible plane of symmetry. One such example would be: Here the carbons marked with an asterisk are stereogenic centres (the asterisk is not used to mark ...
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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?
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Which would have higher priority according to CIP rule (Cyclic Substituents)? [duplicate]

So if we were to assign E-Z nomenclature to this compound : then the Ethyl group would obviously have more priority than methyl group, but I am confused whether out of Cyclopropane and Cyclobutane ...
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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 ...
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1answer
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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?
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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.
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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 ...
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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, ...
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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 ...
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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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1answer
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Number of geometrical isomers?

How many geometrical isomers will exist for compound of this type which has cycloalkene having carbon atoms greater or equal to 8 in the middle of chain? I know that due to ring in middle of chain ...
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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?
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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 ...
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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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How to check for geometrical isomerism in cyclic compounds?

I have no problem with identifying whether a given molecule has geometrical isomerism if it's not cyclic. But cyclic compounds are confusing for me. For example, how to check whether the following ...
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1answer
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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 ...
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E/Z stereoisomers : assigning priorities with a cycloalkane group

For the following compound Right hand side of double bond: $\ce{CO2CH3}$ is highest priority due to the extra carbon (as we work along both chains) But for the left hand side oft he double bond I ...
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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?
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How to calculate the number of geometrical isomers in allenes?

Can someone explain how to calculate the number of geometrical isomers in allenes like $\ce{CH3-(CH=CH)4-CH3}$ or $\ce{CH3-(CH=CH)5-CH3}$
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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-...
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1answer
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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...
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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 ...
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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 ...
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2answers
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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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isomerism in coordination complexes

Is there any difference between geometrical and cis-trans isomerism in coordination complexes, because in my book it is given that complexes of the form [Ma4bc] does not show cis-trans isomerism but ...
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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 ...
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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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1answer
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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. ...
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Number of geometrical isomers when a cyclic ring is involved along with axis of symmetry

This is an question from my Chemistry study material and it asks to find the number of Geometrical Isomers of the following compound in the picture. Basically the method/formula given in my book to ...
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Why unsaturated fats are usually cis?

I've been studying organic chemistry and I think trans fats are actually more stable than cis fats. This is because the steric hindrance (for trans) would be lower and the molecule energy would be ...
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2answers
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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?
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Geometric isomers of substituted methylidenecyclohexane?

My thoughts on the problem: I am sort compound of sure C and D will not show geometric isomerism because of the same groups (H and H) attached. In compound A and B, suppose I swap the positions of H ...
2
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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 ...
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1answer
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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 !