This document discusses symmetry elements and symmetry operations in group theory and chemistry. It defines the key symmetry elements - identity (E), proper rotation axes (Cn), mirror planes (σ), inversion centers (i), and improper rotation axes (Sn). It provides examples of how these elements apply to common molecular structures like water, methane, benzene, and transition metal complexes. The document also explains the different types of mirror planes and how the symmetry operations are generated from each element.
1. What is the steady state approximation
2.Definition of Steady state approximation
3. In Chemical kinetics in steady state state approximation
4. Mechanism involving in steady state approximation
5. rate of formation, using steady state approximation plot
Classification Of Mechanisms, Ligand Substitution In Octahedral Complexes Without Breaking Metal-ligand Bond, Substitution Reaction In Square Planar Complexes, Factors Which Affect The Rate Of Substitution, Trans Effect (Labilizing Effect), Theories and applications Of Trans Effect
Phosphine as ligand by Dr Geeta TewariGeeta Tewari
This presentation describes about the nature of phosphine ligands, bonding and reactions of metal phosphine containing complexes. Also explains the similarity and differences of phosphine ligand with NH3 and CO ligands.
The video lecture for this presentation is available at the following link on YouTube
https://youtu.be/3sxal579RNM
The presenation will be useful for Ug/PG (Chemistry) students
1. What is the steady state approximation
2.Definition of Steady state approximation
3. In Chemical kinetics in steady state state approximation
4. Mechanism involving in steady state approximation
5. rate of formation, using steady state approximation plot
Classification Of Mechanisms, Ligand Substitution In Octahedral Complexes Without Breaking Metal-ligand Bond, Substitution Reaction In Square Planar Complexes, Factors Which Affect The Rate Of Substitution, Trans Effect (Labilizing Effect), Theories and applications Of Trans Effect
Phosphine as ligand by Dr Geeta TewariGeeta Tewari
This presentation describes about the nature of phosphine ligands, bonding and reactions of metal phosphine containing complexes. Also explains the similarity and differences of phosphine ligand with NH3 and CO ligands.
The video lecture for this presentation is available at the following link on YouTube
https://youtu.be/3sxal579RNM
The presenation will be useful for Ug/PG (Chemistry) students
This presentation will be helpful to beginners on chemical aspects of group theory. Also this ppt consists of videos on mirror plane symmetry and rotational axis of symmetry
Crown ethers
NOMENCLATURE
GENERAL SYNTHESIS OF CROWN ETHER
AZA CROWN
CRYPTAND
APPLICATIONS
1. SYNTHETIC APPLICTION
Esterification
Saponification
Anhydride formation
Potassium permanganate oxidation
Aromatic substitution reactions
Elimination reactions
Displacement reaction
Generation of carbenes
Superoxide anion
Alkylations – 1. o-alkylations
2. c-alkylations
3. n-alkylations
2. ANALYTICAL APPLICATION
Determination of gold in geological samples
Super critical fluid extraction of trace metal from solid and liquid materials
Application of ionic liquids in analytical chemistry
Oxidation and determination of aldehydes
Crown ethers are used in the laboratory as phase transfer catalyst
OTHER APPLICATION
It is used in photocynation
Resolution of racemic mixture
Benzoin condensation
Hetrocyclisation
Synthesis of furanones
Acetylation of secondary amines in presence of primary amine
Cyclohexane exists in different conformations viz chair, boat, twist boat and half chair. These conformations possess different energies. Therefore they differ in energy.
Stability and reactions of n heterocyclic carbenesDaniel Morton
Carbenes are two-coordinate carbon compounds with a sextet of electrons on the carbon. Most of them the indicate instability and high reactivity. Stable carbenes lead to new possibilities and fields. This overview introduces N-heterocyclic carbenes, a stable class of these unusual compounds.
Contributed by:
Özlem Urcan, F. Richard Kurth, Jonas Renner (Undergraduates), University of Utah, 2016
This presentation will be helpful to beginners on chemical aspects of group theory. Also this ppt consists of videos on mirror plane symmetry and rotational axis of symmetry
Crown ethers
NOMENCLATURE
GENERAL SYNTHESIS OF CROWN ETHER
AZA CROWN
CRYPTAND
APPLICATIONS
1. SYNTHETIC APPLICTION
Esterification
Saponification
Anhydride formation
Potassium permanganate oxidation
Aromatic substitution reactions
Elimination reactions
Displacement reaction
Generation of carbenes
Superoxide anion
Alkylations – 1. o-alkylations
2. c-alkylations
3. n-alkylations
2. ANALYTICAL APPLICATION
Determination of gold in geological samples
Super critical fluid extraction of trace metal from solid and liquid materials
Application of ionic liquids in analytical chemistry
Oxidation and determination of aldehydes
Crown ethers are used in the laboratory as phase transfer catalyst
OTHER APPLICATION
It is used in photocynation
Resolution of racemic mixture
Benzoin condensation
Hetrocyclisation
Synthesis of furanones
Acetylation of secondary amines in presence of primary amine
Cyclohexane exists in different conformations viz chair, boat, twist boat and half chair. These conformations possess different energies. Therefore they differ in energy.
Stability and reactions of n heterocyclic carbenesDaniel Morton
Carbenes are two-coordinate carbon compounds with a sextet of electrons on the carbon. Most of them the indicate instability and high reactivity. Stable carbenes lead to new possibilities and fields. This overview introduces N-heterocyclic carbenes, a stable class of these unusual compounds.
Contributed by:
Özlem Urcan, F. Richard Kurth, Jonas Renner (Undergraduates), University of Utah, 2016
A carbene is any neutral carbon species which contains a non-bonding valance pair of electrons.
Contributed by Alison Brown & Nathan Buehler, Undergraduates, University of Utah
introduction to photosynthesis, artificial photosynthesis, history, photolytic cell, how does AP work, artificial leaf, applications, pros and cons of the technology.
Plants produce a vast and diverse organic compounds, which do not appear to participate directly in growth and development.These substances traditionally referred to as secondary metabolites which terpenes are one of them.
Biosynthesis lectures by Dr. Refaat HamedRefaat Hamed
This is a series of five lectures for 4th year Pharmacy Students (Assiut University) as part of the "Applied Pharmacognosy" course. The lectures cover the biosynthesis of many classes of natural products (e.g. Alkaloids, Polyketides, Flavonoids,..etc. Special emphasis is on the recent trends in biosynthesis research.
more chemistry contents are available
1. pdf file on Termmate: https://www.termmate.com/rabia.aziz
2. YouTube: https://www.youtube.com/channel/UCKxWnNdskGHnZFS0h1QRTEA
3. Facebook: https://web.facebook.com/Chemist.Rabia.Aziz/
4. Blogger: https://chemistry-academy.blogspot.com/
ORGANIC CHEMISTRY
After reading this module, you should be able to . . .
10.01 Identify that if all parts of a body rotate around a fixed
axis locked together, the body is a rigid body. (This chapter
is about the motion of such bodies.)
10.02 Identify that the angular position of a rotating rigid body
is the angle that an internal reference line makes with a
fixed, external reference line.
10.03 Apply the relationship between angular displacement
and the initial and final angular positions.
10.04 Apply the relationship between average angular velocity, angular displacement, and the time interval for that displacement.
10.05 Apply the relationship between average angular acceleration, change in angular velocity, and the time interval for
that change.
10.06 Identify that counterclockwise motion is in the positive
direction and clockwise motion is in the negative direction.
10.07 Given angular position as a function of time, calculate the
instantaneous angular velocity at any particular time and the
average angular velocity between any two particular times.
10.08 Given a graph of angular position versus time, determine the instantaneous angular velocity at a particular time
and the average angular velocity between any two particular times.
10.09 Identify instantaneous angular speed as the magnitude
of the instantaneous angular velocity.
10.10 Given angular velocity as a function of time, calculate
the instantaneous angular acceleration at any particular
time and the average angular acceleration between any
two particular times.
10.11 Given a graph of angular velocity versus time, determine the instantaneous angular acceleration at any particular time and the average angular acceleration between
any two particular times.
10.12 Calculate a body’s change in angular velocity by
integrating its angular acceleration function with respect
to time.
10.13 Calculate a body’s change in angular position by integrating its angular velocity function with respect to time.
2024.06.01 Introducing a competency framework for languag learning materials ...Sandy Millin
http://sandymillin.wordpress.com/iateflwebinar2024
Published classroom materials form the basis of syllabuses, drive teacher professional development, and have a potentially huge influence on learners, teachers and education systems. All teachers also create their own materials, whether a few sentences on a blackboard, a highly-structured fully-realised online course, or anything in between. Despite this, the knowledge and skills needed to create effective language learning materials are rarely part of teacher training, and are mostly learnt by trial and error.
Knowledge and skills frameworks, generally called competency frameworks, for ELT teachers, trainers and managers have existed for a few years now. However, until I created one for my MA dissertation, there wasn’t one drawing together what we need to know and do to be able to effectively produce language learning materials.
This webinar will introduce you to my framework, highlighting the key competencies I identified from my research. It will also show how anybody involved in language teaching (any language, not just English!), teacher training, managing schools or developing language learning materials can benefit from using the framework.
Normal Labour/ Stages of Labour/ Mechanism of LabourWasim Ak
Normal labor is also termed spontaneous labor, defined as the natural physiological process through which the fetus, placenta, and membranes are expelled from the uterus through the birth canal at term (37 to 42 weeks
A Strategic Approach: GenAI in EducationPeter Windle
Artificial Intelligence (AI) technologies such as Generative AI, Image Generators and Large Language Models have had a dramatic impact on teaching, learning and assessment over the past 18 months. The most immediate threat AI posed was to Academic Integrity with Higher Education Institutes (HEIs) focusing their efforts on combating the use of GenAI in assessment. Guidelines were developed for staff and students, policies put in place too. Innovative educators have forged paths in the use of Generative AI for teaching, learning and assessments leading to pockets of transformation springing up across HEIs, often with little or no top-down guidance, support or direction.
This Gasta posits a strategic approach to integrating AI into HEIs to prepare staff, students and the curriculum for an evolving world and workplace. We will highlight the advantages of working with these technologies beyond the realm of teaching, learning and assessment by considering prompt engineering skills, industry impact, curriculum changes, and the need for staff upskilling. In contrast, not engaging strategically with Generative AI poses risks, including falling behind peers, missed opportunities and failing to ensure our graduates remain employable. The rapid evolution of AI technologies necessitates a proactive and strategic approach if we are to remain relevant.
The French Revolution, which began in 1789, was a period of radical social and political upheaval in France. It marked the decline of absolute monarchies, the rise of secular and democratic republics, and the eventual rise of Napoleon Bonaparte. This revolutionary period is crucial in understanding the transition from feudalism to modernity in Europe.
For more information, visit-www.vavaclasses.com
Unit 8 - Information and Communication Technology (Paper I).pdfThiyagu K
This slides describes the basic concepts of ICT, basics of Email, Emerging Technology and Digital Initiatives in Education. This presentations aligns with the UGC Paper I syllabus.
Operation “Blue Star” is the only event in the history of Independent India where the state went into war with its own people. Even after about 40 years it is not clear if it was culmination of states anger over people of the region, a political game of power or start of dictatorial chapter in the democratic setup.
The people of Punjab felt alienated from main stream due to denial of their just demands during a long democratic struggle since independence. As it happen all over the word, it led to militant struggle with great loss of lives of military, police and civilian personnel. Killing of Indira Gandhi and massacre of innocent Sikhs in Delhi and other India cities was also associated with this movement.
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1. Department of Chemistry
Central university of rajasthan
Presentation on
SYMMETRY ELEMENTS AND SYMMETRY OPERATIONS
Submitted to :-
DR. Malli bhanuchandra
Astt. Professor
Department of chemistry
Submitted by :-
Roopendra singh madhukar
Int. M.sc. B.ed. Chemistry
2015imsbch023
2. GROUP THEORY :-
Fundamentals of group theory are developed by Evariste Galois.
It is the study of symmetry.
It is purely mathematics concept which has wide applications in physical
sciences.
When applied to Chemistry, it can be used, for example,
to…….
to predict whether or not a molecule has a dipole moment
to predict if a molecule will show optical activity
To derive selection rules for spectroscopic transitions
to determine which AOs to be used to construct hybrid orbitals.
to predict which molecular vibrations lead to IR spectra.
to label and designate MOs
etc.
3. What is symmetry ?
Symmetry is when a shape looks identical to its original shape
after being flipped or turned.
Nature loves symmetry
Most objects found in nature have symmetry
Symmetry is associated with beauty
e.g. Flowers, diamonds, butterflies, snail shells,leaves, etc
are all beautiful, highly symmetrical because of
harmony and attractiveness of their
forms and proportions.
5. Symmetry in the human body :-
A flower, crystal or a molecule, is said to have symmetry if it has two or
more orientations in the space that are indistinguishable. The criteria
for
Judging these are based on symmetry elements and symmetry
6. What is symmetry element and symmetry operation ?
A symmetry element is a geometrical entity such
as a line, a plane, or a point about which one can
perform an operation of rotation, reflection, or
inversion.
A symmetry operation is movement of a
molecule/object about an symmetry element such
that resulting configuration is indistinguishable
from the original.
A symmetry operation will transform a molecule
into an equivalent or identical configuration.
for example:- H2O molecule is rotated about an
axis through oxygen atom and bisecting H-O-H
bond angle, through 180.
0
C2
a b b a a b
I II III
7. The configurations I, II and III are
indistinguishable, therefore this operation is a
symmetry operation.
The symmetry element is the imaginary line
(axis).
The symmetry operation is the rotation of a
molecule about this axis through 180.
I and II are equivalent.
II and III are equivalent.
But I and III are identical.
0
8. Symmetry elements and symmetry operations :-
Symmetry Elements Symmetry Operations
1. Identity [E] Doing nothing
2. Proper Rotation axis or
Axis of Symmetry [Cn]
Rotation about the axis through
some
angle
3. Mirror Plane or
Plane of Symmetry []
Reflection about the plane
4. Inversion Centre or
Centre of Symmetry [ i ]
Inversion
{ inversion is a reflection about a
point}
5. Improper Rotation axis or
Rotation- Reflection axis [Sn]
Rotation about an axis through
some
angle followed by a reflection in
a plane
9. 1. Identity [E] :-
This is an operation which brings molecule back
to its original orientation.
This operation does nothing. It is simplest of all
the symmetry elements.
It is the only element/operation possessed by all
molecules.
It is denoted by E.
for example:- CHBrFCl
10. 2. Axis of symmetry [Cn] :-
It is called n-fold rotational axis.
If the rotation of a molecule about an axis through
some angle results in a configuration which is
indistinguishable from the original, then the
molecule is said to possess a proper rotation
axis.
It is denoted as Cn.
n is order of rotation axis.
Rotation about an axis by an angle of 360/n.
For example:- water molecule
a b
b a1800
Order of rotation axis = 2
Symmetry element = C2 axis
Operations = C2
1, C2
2 = E
11. Operation 2: Cn, Proper Rotation:
Rotation about an axis by an angle of 2/n = 360/n
How about: NFO2?
H2O NH3
C2 C3
14. Principal and SubsidiaryAxes :
In molecules with more than one axis of symmetry, the axis with the highest fold
symmetry (highest n in Cn) is called the Principal Axis. The other axes are called
Subsidiary Axes.
In case there are more than one axes of same order, the axis passing through
maximum number of atoms is the Principal Axis.
The axis of symmetry can be C∞ .
H Cl H H C∞
HCl H2
15. Symbol of the
proper rotation
axis
Order of rotation
axis
3600 /n
1. C2 (= C6
3) 2 180
2. C3 (= C6
2) 3 120
3. C4 4 90
4. C5 5 72
5. C6 6 60
Symmetry operations associated with axis of symmetry :-
In general a Cn axis can generated n
operation
Cn , Cn
2, Cn
3, Cn
4......... Cn
n
Cn
n = E
Cn
n+1 = Cn
Cn
n+2 = Cn
2 and so on
22. The highest order rotation axis
is the principal axis
and it is chosen as the z axis
Iron pentacarbonyl, Fe(CO)5
C3 axis
What other rotational axes do we have here?
23. 3. Plane of symmetry [] :-
A mirror plane is an imaginary plane which
divides a molecules into two equal halves such
that one half is the exact mirror image of the
other.
It is denoted by ‘’.
Atoms on the surface of plane remain unshifted
during reflection.
Classification of mirror planes:-
Vertical plane(v) :- The principal axis of symmetry lies
in the this plane.
Horizontal plane (h):- The principal axis of symmetry
is perpendicular to the plane.
Dihedral plane (d):- The plane passing through the
principal axis but passing in between two subsidiary
axis, is the dihedral plane.
27. 4. Inversion centre of centre of symmetry :-
If a line drawn through a point in a molecule and
extended in both directions encounters equivalent
point in either, the point through which line is
drawn is called an inversion centre.
It denoted as ‘i’.
29. 5. Improper axis of symmetry or rotation-reflection axis or alternate axis of
symmetry:-
If a molecule is rotated about an axis through some
angle and the resulting configuration is reflected in a
plane perpendicular to this axis, if new configuration
is indistinguishable from the original, then the axis is
called an improper axis.
It denoted as ‘Sn’
The symmetry element is denoted as S2.
a
b
1800
b
a a
b
31. Operations generated by Sn :-
The no. Of operations generated by Sn depends
on whether n is odd or even.
If ‘n’ is even then generated operations are ‘n’.
If ‘n’ is odd then generated operations are ‘2n’.
32. References :-
Molecular symmetry and group theory by
Robert L. Carter.
Chemical Applications of Group Theory by F.
Albert Cotton.
http://symmetry.otterbein.edu/tutorial/methane
.html
Google
Editor's Notes
Symmetry in nature :-
5
Order of rotation axis = 2
Symmetry element = C2 axis
Operations = C21, C22 = E