Thanks for saving my life. My prof had earlier explained this today in class, and I felt like I didn't pass through college to be here, but your simple explanation makes it so clear and understandable. Vielen Dank, from Munster, Germany
"I felt like I didn't pass through college to be here" is so real, not knowing this made me feel like the biggest fraud known to mankind, thanks for the comment it perfectly encapsulated how i was feeling
@swifty2323 yeah bro/sis Sometimes it always feels like that then we encounter the "ah"! moment when we realise this is easy and we are more than enough! In German we say "ich schaffe das"! Kindly connect if you can bro👍🏽
I am currently reading through Atkin's Molecular Quantum Mechanics book. The chapter on Group Theory is awfully abstract and hard to visualize (at least for me). These animations help a lot. Thanks!
The subscript on sigma seems hard to determine in for example para-dichlorobenzene. There are 3 2-fold rotation axes, so which becomes the "primary" rotation axis in this case?
Now, I see. If you assign the main rotation axis as z axis, the σh plane is horizontal. The "horizontal" isn't the relative position between the plane and the axis, but the relative position of the plane when picking the main rotation axis as the reference.
Hi - we also have a PDF that walks through this topic. Click on "Introduction to Symmetry Operations and Point Groups" here: www.ccdc.cam.ac.uk/Community/educationalresources/teaching-modules/
In chemistry, sigma (σ) planes of symmetry are used to describe symmetry elements in molecules. The key difference between a sigma d (σd) plane of symmetry and a sigma v (σv) plane of symmetry lies in their orientation and the type of symmetry they represent: 1. Sigma d (σd) Plane of Symmetry: - A sigma d plane of symmetry is a plane that bisects the molecule in such a way that it divides the molecule into two identical halves. - This plane passes through the center of the molecule and is perpendicular to the principal molecular axis, which means it goes through the nucleus of the central atom. - Sigma d symmetry is often associated with linear molecules, such as diatomic molecules like O2 and N2. 2. Sigma v (σv) Plane of Symmetry: - A sigma v plane of symmetry is a vertical plane that passes through the molecule. - This plane is perpendicular to the principal molecular axis and is parallel to one of the molecular bonds. - Sigma v symmetry is typically associated with molecules that have a vertical axis of symmetry, such as planar molecules like benzene (C6H6). In summary, sigma d planes of symmetry bisect the molecule perpendicular to the principal axis, while sigma v planes of symmetry are vertical planes that are parallel to molecular bonds. Understanding these symmetry elements is essential in the study of molecular symmetry and spectroscopy in chemistry.
Hi Ben, Ethane does not have a C6 rotation axis. This is because if you are only rotating the molecule, you need a 120 degrees rotation to overlap with the initial structures, hence the C3 axis. Ethane in a staggered conformation has also an improper rotation axis S6, where indeed the rotation is of 60 degrees, and then the rotation is followed by a reflection, hence overlapping with the initial structure. For a more visual explanation, both the rotation and improper rotation axes are demonstrated on the molecule from 07:10 in this video and they can also be seen in the example on the Symmetry@Otterbein web resource symotter.org/tutorial/ethanes I hope this helps! CCDC Team
A very clear exposition of the principles of symmetry. I will show it to my students. But please do not confuse the words "principle" and "principal". You should refer to the C6 in benzene as the "principal" axis.
Hello! If the video is not loading well on the device, you can find this introduction also in pdf format on our website. You can find it in the Teaching Modules webpage linked below, where you can download the resource: Introduction to Symmetry Operations and Point Groups. Go here: www.ccdc.cam.ac.uk/Community/educationalresources/teaching-modules/
Thanks for saving my life. My prof had earlier explained this today in class, and I felt like I didn't pass through college to be here, but your simple explanation makes it so clear and understandable. Vielen Dank, from Munster, Germany
"I felt like I didn't pass through college to be here" is so real, not knowing this made me feel like the biggest fraud known to mankind, thanks for the comment it perfectly encapsulated how i was feeling
@swifty2323 yeah bro/sis
Sometimes it always feels like that then we encounter the "ah"! moment when we realise this is easy and we are more than enough!
In German we say "ich schaffe das"!
Kindly connect if you can bro👍🏽
You just saved my life for an exam I have today, lecture notes and office hours haven't helped at all, but this made it so much easier to understand.
Best of luck in your exam!
Amazing help! Symmetry can be a mind bender and there are very few good videos on the matter. Cheers :)
I've got a test tomorrow, and I keep messing up
Me too
Who doesn't 😂
I have mine later today. 😅
🎉I have test tomorrow 😂😮
I have mine today 😢
I have a gemology exam in a few days and missed this class. This video is very helpful thanku.
This was so clear and easy to understand, thank you!
your explanation is just amazing.
great video really good way of teaching
Loved it. Thank you for the video.
I am currently reading through Atkin's Molecular Quantum Mechanics book. The chapter on Group Theory is awfully abstract and hard to visualize (at least for me). These animations help a lot. Thanks!
Realmente as figuras não são muito elucidadtivas nesse livro texto.
The subscript on sigma seems hard to determine in for example para-dichlorobenzene. There are 3 2-fold rotation axes, so which becomes the "primary" rotation axis in this case?
still trying to get my head around horizontal and vertical planes of symmetry
🙂💯
Ah! I've just gotten used to H-M notation, now I need to learn Schoenflies!
The h stands for the mirror is horizontal with respect to the rotation axis. But the C6 axis of benzene is vertical to the σh plane. I don't get it.
Now, I see. If you assign the main rotation axis as z axis, the σh plane is horizontal. The "horizontal" isn't the relative position between the plane and the axis, but the relative position of the plane when picking the main rotation axis as the reference.
Not enough information, the examples go through too quickly, couldn't follow properly.
Hi - we also have a PDF that walks through this topic. Click on "Introduction to Symmetry Operations and Point Groups" here: www.ccdc.cam.ac.uk/Community/educationalresources/teaching-modules/
could you explain why the planes are sigma d but not sigma v? your videos really help me a lot, thank you so much.
Just did this in class today. Basically sigma v is when the plane cuts along the z axis and sigma d is when it doesn’t.
In chemistry, sigma (σ) planes of symmetry are used to describe symmetry elements in molecules. The key difference between a sigma d (σd) plane of symmetry and a sigma v (σv) plane of symmetry lies in their orientation and the type of symmetry they represent:
1. Sigma d (σd) Plane of Symmetry:
- A sigma d plane of symmetry is a plane that bisects the molecule in such a way that it divides the molecule into two identical halves.
- This plane passes through the center of the molecule and is perpendicular to the principal molecular axis, which means it goes through the nucleus of the central atom.
- Sigma d symmetry is often associated with linear molecules, such as diatomic molecules like O2 and N2.
2. Sigma v (σv) Plane of Symmetry:
- A sigma v plane of symmetry is a vertical plane that passes through the molecule.
- This plane is perpendicular to the principal molecular axis and is parallel to one of the molecular bonds.
- Sigma v symmetry is typically associated with molecules that have a vertical axis of symmetry, such as planar molecules like benzene (C6H6).
In summary, sigma d planes of symmetry bisect the molecule perpendicular to the principal axis, while sigma v planes of symmetry are vertical planes that are parallel to molecular bonds. Understanding these symmetry elements is essential in the study of molecular symmetry and spectroscopy in chemistry.
Awesome demonstration.I have subscribed your channel.
if the ethane has a staggered structure would it be possible that it possesses a c6 axis rather than a c3?
Hi Ben,
Ethane does not have a C6 rotation axis. This is because if you are only rotating the molecule, you need a 120 degrees rotation to overlap with the initial structures, hence the C3 axis.
Ethane in a staggered conformation has also an improper rotation axis S6, where indeed the rotation is of 60 degrees, and then the rotation is followed by a reflection, hence overlapping with the initial structure.
For a more visual explanation, both the rotation and improper rotation axes are demonstrated on the molecule from 07:10 in this video and they can also be seen in the example on the Symmetry@Otterbein web resource symotter.org/tutorial/ethanes
I hope this helps!
CCDC Team
A very clear exposition of the principles of symmetry. I will show it to my students. But please do not confuse the words "principle" and "principal". You should refer to the C6 in benzene as the "principal" axis.
فوتي فالموضوع دغري تكفين الاختبار بعد كم ساعه
I wish I had that flowchart when I took undergraduate inorganic
Where you are from?You are so nice at teaching.🎉
Inorganic?
Cant see the video clearly
Hello! If the video is not loading well on the device, you can find this introduction also in pdf format on our website. You can find it in the Teaching Modules webpage linked below, where you can download the resource: Introduction to Symmetry Operations and Point Groups.
Go here: www.ccdc.cam.ac.uk/Community/educationalresources/teaching-modules/
v includes rotation axis and other doesnt
Tysmmmm
U used 12min to explain something that my professor didn't explain very well in 120min...