ROTATION AXIS ON TETRAHEDRON AND ORGANIC MOLECULES

Last Update 24/ 08/ 2000

in English/ in Esperanto/ in French/ in Portuguese

Introduction

This frame is directed to the study on two fields: in one option the rotation axis study on tetrahedral and lower symmetry objects like pyramids with triangular base and different components on the corners. The other option enables the absolute configuration study on organic molecules with at least one saturated carbon.

Description of the application in symmetry

The default figure directs the four-fold inversion axis perpendicular to this screen. Depending on the selected object by clicking on the little structures on the right side of the figure the new axis in this orientation may be the two-fold axis. It can be operated by a push and drag mouse action on the green square on the horizontal scrolling bar. On the other hand, by a similar action on the vertical scrolling bar a three-fold axis may be perpendicular to this screen, depending on the symmetry of the selected object.

Suggested symmetry exercise

Verify which of the available structures exhibit the two-fold axis, which the three-fold axis on the orientation mentioned above and which exhibit more than one symmetry axis.

Description of the application in organic chemistry

The absolute configuration of an asymmetric carbon of a chiral organic molecule can be determined with the aid of a framework molecular model. This conclusion is obtained after drawing and imagining the molecule in space, when a molecular model is not available. It requires experience and vision in three dimensions. However, the molecule is not always presented with the appropriate orientation for the direct determination of its absolute configuration.

For example, when the group of lowest priority is directed away from the viewer the determination of the configuration is direct, just having to trace an arrow in the decreasing priority sense of the other groups. If the molecule is presented in any other orientation, it must be rotated until reaching a convenient orientation.

Therefore this application was developed aiming to help the students determine the absolute configuration of either imaginary or real molecules while their spatial vision is being developed.

Suggested organic chemistry exercise

Determine the absolute configuration of bromochlorofluoromethane supposing that the atom of bromine is the red sphere, chlorine green, fluorine blue and hydrogen yellow.

Please send your comments.

Table of subjects.
Presentation
Chemistry Analytical Chromatography
Elemental organic analysis
Volumetric analysis, simulation
Crystallography 3 fold screw axis
4 fold inversion axis on tetrahedron
5 fold rotation axis absent in crystallography
Binary axis and reflection plane in stereographic projection
Bravais lattices
Conic sections under symmetry operators
Converting from spherical coordinates to stereographic projection
Crystal lattice and unit cell
Determination of unit cell
Elements of symmetry in action - animation
Elements of symmetry in action - cube game
Elements of symmetry in action - dodecahedron game
Elements of symmetry in action - icosahedron game
Elements of symmetry in action - octahedron game
Elements of symmetry in action - tetrahedron game
Ewald sphere and crystal measurements
Extinctions
Five classes in the cubic system
Five classes in the rhombohedral system
From tetrahedron to prism
Gnomonic projection
Improper symmetry axis
Miller indices
Miller indices - animation
Miller indices - cube game
Miller indices - octahedron game
Miller indices - rhombic dodecahedron game
Miller indices - tetrahedron game
Mirror plane
Mirror planes and Miller indices game - tetrahedron
Orientations of the cube
p2mm
Plane symmetry groups
Question on point group
Rotation axis in octahedron and Werner compounds
Rotation axis on tetrahedron and organic molecules
Rotation of objects about an arbitrary axis
Rotation of the parallel and stereographic projections of the cube
Rotation of the stereographic and parallel projection of the cube III
Seven faces in stereographic projection
Seven classes in the hexagonal system
Seven classes in the tetragonal system
Six elements of symmetry in seven orientations
Spherical projection of the octahedron
Stereographic projection
Stereographic projection of six polyhedra in different orientations
Straight line equations and symmetry elements
Symmetry, 2 fold axis
Symmetry, 2, 3 and 6 fold axis in benzene
Symmetry, 3 fold axis in the cube
Symmetry, 4 fold axis in the cube
Symmetry, 4 fold axis in the unit cell of gold
Symmetry elements and Miller indices game
Symmetry elements and Miller indices game - octahedron
Symmetry in art and in crystallography
Three classes in the monoclinic system
Three classes in the orthorhombic system
Twin crystals
Two classes in the triclinic system
Unit cell in hexagonal net
General Butane conformations
Density
Electrochemical cell
Ethane conformations
Oxidation and reduction
Resources of chemical-ICT: water, health and symmetry
Solid and liquid gold