Search for notes by fellow students, in your own course and all over the country.
Browse our notes for titles which look like what you need, you can preview any of the notes via a sample of the contents. After you're happy these are the notes you're after simply pop them into your shopping cart.
Title: Molecular geometry notes
Description: Chemistry notes of molecular geometry
Description: Chemistry notes of molecular geometry
Document Preview
Extracts from the notes are below, to see the PDF you'll receive please use the links above
Symmetry Operations and Elements
•
The goal for this section of the course is to understand how symmetry arguments can be
applied to solve physical problems of chemical interest
...
•
A symmetry element is an imaginary geometrical construct about which a symmetry
operation is performed
...
•
A symmetry
t operation
ti carries
i every point
i t in
i the
th object
bj t into
i t an equivalent
i l t point
i t or the
th
identical point
...
•
The symmetry of a molecule or ion can be described in terms of the complete collection of
symmetry operations it possesses
...
The more
symmetry operations a molecule has, the higher its symmetry is
...
The Identity Operation (E)
•
The simplest of all symmetry operations is identity, given the symbol E
...
If it possesses no other symmetry, the object is said to be
asymmetric
...
It exists for every object, because the
object itself exists
...
•
In addition,
addition identity is often the result of carrying out a particular operation successively a
certain number of times,
i
...
, if you keep doing the same operation repeatedly, eventually you may bring the object
back to the identical (not simply equivalent) orientation from which was started
...
•
Thus, if a series of repeated operations carries the object back to its starting point, the result
would be identified simply as identity
...
•
If a molecule has rotational symmetry Cn , rotation by
2/n = 360°/n brings the object into an equivalent
position
...
•
If the molecule has one or more rotational axes, the
one with the highest value of n is the principal axis of
rotation
...
•
Multiple iterations are designated by a superscript,
e
...
three successive C4 rotations are identified as C43
•
The C42 and C44 operations are preferably identified as
the simpler C2 and E operations,
operations respectively
...
•
The C2' and C2" axes of a planar MX4 molecule
...
•
Only two notations are needed for the four axes,
axes because both C2’ axes are said to belong to
the same class, while the two C2’’ axes belong to a separate class
...
e
...
•
In listing the complete set of symmetry
operations for a molecule, operations of the
same class are designated by a single notation
preceded by a coefficient indicating the number
of equivalent operations comprising the class
...
g
Title: Molecular geometry notes
Description: Chemistry notes of molecular geometry
Description: Chemistry notes of molecular geometry