Chapter 4. Molecular Symmetry

Slides:

Advertisements

Similar presentations

Equivalent Positions in 3-D

Advertisements

Ideas for Exercises for the K-12 Classroom

Group Theory in Chemistry

A Science of Aesthetics Transformations You Cannot See.

Symmetry and Group Theory

Molecular Symmetry Symmetry Elements Group Theory

Lecture 28 Point-group symmetry I

3-Dimensional Crystal Structure

1 Watkins/Fronczek - Space Groups Translational + Rotational Symmetry Introduction to Space Groups.

Michael P. Sigalas Nickolas D. Charistos

Today in Inorganic…. Symmetry elements and operations Properties of Groups Symmetry Groups, i.e., Point Groups Classes of Point Groups How to Assign Point.

Today in Inorganic…. Uses of Symmetry in Chemistry Symmetry elements and operations Properties of Groups Symmetry Groups, i.e., Point Groups Previously:

Vibrational Spectroscopy CHE 626 Alex Nazarenko

What is similar about the shapes in each row? 1. AHOTW 2. CEHO 3. HINO Z.

Lecture # 8 Molecular Symmetry

Chapter 4 Molecular Symmetry

Computer Animations of Molecular Vibration Michael McGuan and Robert M. Hanson Summer Research 2004 Department of Chemistry St. Olaf College Northfield,

PH0101 UNIT 4 LECTURE 3 CRYSTAL SYMMETRY CENTRE OF SYMMETRY

3-D figures. Reflectional Symmetry For 2D figure: If a plane figure can be divided by a line into two identical parts and these parts are mirror images.

Symmetry Motif: the fundamental part of a symmetric design that, when repeated, creates the whole pattern Operation: some act that reproduces the.

Symmetry and Group Theory

Symmetry operation motion of molecule which leaves it indistinguishable from before. Symmetry element plane, line (axis) or point (centre) about which.

1 Physical Chemistry III (728342) Chapter 5: Molecular Symmetry Piti Treesukol Kasetsart University Kamphaeng Saen Campus.

CH4 – four-fold improper rotation

Ch121 X - Symmetry Symmetry is important in quantum mechanics for determining molecular structure and for interpreting spectroscopic information. In addition.

1 Internal Order and Symmetry GLY 4200 Fall, 2015.

Symmetry Edward A. Mottel Department of Chemistry Rose-Hulman Institute of Technology.

Today in Inorganic…. Symmetry elements and operations Properties of Groups Symmetry Groups, i.e., Point Groups Classes of Point Groups How to Assign Point.

Symmetry Figures are identical upon an operation Reflection Mirror Line of symmetry.

Ch 4 Lecture 1 Symmetry and Point Groups I.Introduction A.Symmetry is present in nature and in human culture.

Group Theory and Spectroscopy

1 CH6. Symmetry Symmetry elements and operations Point groups Character tables Some applications.

Lecture 28 Point-group symmetry I. Molecular symmetry A typical conversation between chemists … Symmetry is the “language” all chemists use every day.

Isomers Isomers: different compounds with the same molecular formula Constitutional isomers: isomers with a different connectivity Stereoisomers: isomers.

Chapter 7 Stereochemistry. 7.1 Molecular Chirality: Enantiomers.

Symmetry Properties of Molecules

What kind of orbital is this? (A)  g (B)  u * (C)  g * (D)  u (E)  g * side viewview along molecular axis.

Molecular Symmetry Symmetry Elements and Operations Using Symmetry in Chemistry Understand what orbitals are used in bonding Predict.

Dr. Said M. El-Kurdi1 Chapter 4 An introduction to molecular symmetry.

Symmetry and Introduction to Group Theory

Key things to know to describe a crystal

Done by Shobana.N.S 1 BY SHOBANA.N.S QUEEN MARY’S COLLEGE.

Ligand Group Orbitals Created by Chip Nataro (Lafayette College and posted on VIPEr ( on March 27, Copyright.

Today in Inorganic…. 1.Happy Oh 1.Inhuman Transformations 2.Symmetry and Chirality 3.Introducing: Character Tables 5. Symmetry and Vibrational Spectroscopy.

Lecture 34: Symmetry Elements The material in this lecture covers the following in Atkins. 15 Molecular Symmetry The symmetry elements of objects 15.1.

1 The next two parts of the course are closely related, though at first it may not seem so.

Point & Space Group Notations

Chem 222 Spring How to determine point group symmetry H&S Example: BF 3 Is the molecule linear? NO Does the molecule have T d, O h or I.

Chapter 1 Point Group Symmetry.

Crystal Structure and Crystallography of Materials

COVALENT BONDING: ORBITALS Chapter 9. Hybridization The mixing of atomic orbitals to form special molecular orbitals for bonding. The atoms are responding.

Symmetry and Group heory

Periodic patterns.

Internal Order and Symmetry

Internal Order and Symmetry

Crystal Structure and Crystallography of Materials

Symmetry Summary GLY 4200 Lab 5 - Fall, 2017.

Crystals Crystal consist of the periodic arrangement of building blocks Each building block, called a basis, is an atom, a molecule, or a group of atoms.

Symmetry Summary GLY 4200 Lab 5 - Fall, 2012.

Symmetry “the correspondence in size, form and

Symmetry and Introduction to Group Theory

What kind of orbital is this?

Internal Order and Symmetry

Rotation: all points in the original figure rotate, or turn, an identical number of degrees around a fixed point.

Translation (slide) TRANSLATION a slide without turning.

What kind of orbital is this?

Symmetry operations: Transformations mapping the nuclear frame of a molecule onto an indistinguishable version of itself  symmetry elements: symmetry.

Chapter 5 Congruent Triangles.

Symmetry Summary GLY 4200 Lab 5 - Fall, 2019.

Presentation transcript:

Chapter 4. Molecular Symmetry 근정전

Chapter 4. Molecular Symmetry 청와대 본관

Chapter 4. Molecular Symmetry 청와대 영빈관

Chapter 4. Molecular Symmetry 청와대 본관

Chapter 4. Molecular Symmetry 청와대 본관

Chapter 4. Molecular Symmetry 청와대 본관

Chapter 4. Molecular Symmetry

Chapter 4. Molecular Symmetry

Chapter 4. Molecular Symmetry H2O

Symmetry Operation and Symmetry Elements Symmetry Operation:A well-defined, non-translational movement of an object that produces a new orientation that is indistinguishable from the original object. Symmetry Element:A point, line or plane about which the symmetry operation is performed. line: symmetry element 180o rotation: symmetry operation

Four kinds of Symmetry Elements and Symmetry Operations Required in Specifying Molecular Symmetry Proper (rotation) axis (Cn) Mirror plane (s) Center of symmetry or center of inversion (i) Improper (rotation) axis (Sn)

Four kinds of Symmetry Elements and Symmetry Operations Required in Specifying Molecular Symmetry (1) Proper (rotation) axis (Cn) : n-fold symmetry axis. A Cn axis generates n operations. Rotation about Cn axis by 2p/n *1: E : Identity (x1) *2: Right-handed rotation

Four kinds of Symmetry Elements and Symmetry Operations Required in Specifying Molecular Symmetry (1) Proper (rotation) axis (Cn) : n-fold symmetry axis. A Cn axis generates n operations. Rotation about Cn axis by 2p/n * Principal rotational axis: highest-fold rotational axis * If more than one pricnipal axes exist, any one can be the principal axis.

Four kinds of Symmetry Elements and Symmetry Operations Required in Specifying Molecular Symmetry (2) Mirror plane (s) Reflection about the s plane.

Four kinds of Symmetry Elements and Symmetry Operations Required in Specifying Molecular Symmetry (2) Mirror plane (s) Reflection about the s plane. How many mirror planes? 6

Four kinds of Symmetry Elements and Symmetry Operations Required in Specifying Molecular Symmetry (2) Mirror plane (s) Reflection about the s plane. How many mirror planes in linear molecules? C=O N=N 

Four kinds of Symmetry Elements and Symmetry Operations Required in Specifying Molecular Symmetry (2) Mirror plane (s) Reflection about the s plane. * sh : mirror planes perpendicular to the principal axis. *sv : mirror planes containing the principal axis Unless it is sd. * sd : mirror planes bisecting x, y, or z axis or bisecting C2 axes perpendicular to the principal axis.

How to define molecular axes (x, y, z)? 1. The principal axis is the z axis. 2. If there are more than one possible principal axis, then the one that connects the most atoms is the z axis. 3. If the molecule is planar, then the z axis is the principal axis in that plane. The x axis is perpendicular to that plane. 4. If a molecule is planar and the z axis is perpendicular to that plane, then the x axis is the one that connects the most number of atoms.

Four kinds of Symmetry Elements and Symmetry Operations Required in Specifying Molecular Symmetry (3) Center of symmetry or center of inversion (i) Inversion of all objects through the center. i is Pt atom. i is a point in space.

Four kinds of Symmetry Elements and Symmetry Operations Required in Specifying Molecular Symmetry (4) Improper (rotation) axis (Sn) Rotation about an axis by 2p/n followed by a reflection through a plane perpendicular to that axis or vice versa. S6

Four kinds of Symmetry Elements and Symmetry Operations Required in Specifying Molecular Symmetry (4) Improper (rotation) axis (Sn) Rotation about an axis by 2p/n followed by a reflection through a plane perpendicular to that axis or vice versa.

Four kinds of Symmetry Elements and Symmetry Operations Required in Specifying Molecular Symmetry (4) Improper (rotation) axis (Sn) Rotation about an axis by 2p/n followed by a reflection through a plane perpendicular to that axis or vice versa. Sn generates n operations for even n and 2n operations for odd n.

Four kinds of Symmetry Elements and Symmetry Operations Required in Specifying Molecular Symmetry (4) Improper (rotation) axis (Sn) Rotation about an axis by 2p/n followed by a reflection through a plane perpendicular to that axis or vice versa. Sn generates n operations for even n and 2n operations for odd n.

Point Groups Equivalent atoms Equivalent F1, F2, F3 Equivalent Fa, Fb Not equivalent Equivalent symmetry operations Equivalent C2’, C2 3 C2 classes – C2, C2’, C2” - and others symmetry classes C2’ C2’’ Equivalent C2’’, C2’’’ Symmetry classes

Point Groups