Lec 4 - Molecular Geometry and Polarity Chem 221 Thursday July 14 2011 The Structure of Ethane Ethane C2H 6 is the second member of the alkane

Info iconThis preview shows pages 1–8. Sign up to view the full content.

View Full Document Right Arrow Icon
Molecular Geometry and Polarity Chem 221 Thursday July 14, 2011
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
The Structure of Ethane Ethane , C 2 H 6 , is the second member of the alkane family. The four covalent bonds around each carbon are projected towards the corners of a tetrahedron, as in methane. This shape of ethane may be predicted by removing a C-H bond from two methanes and joining the carbons through a C-C bond. C C H H H H H H H H C H H H C H H H C C H H H H H H sigma C-C bond
Background image of page 2
Rotation Around the C-C Bond C C H H H H H H For a C-H bond , there is no change in energy with rotation around the sigma bond. For a C-C bond , there are small energy changes with rotation around the bond that lead to significant structural properties.
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Alkenes: the Carbon-Carbon Double Bond The covalent bonding possibilities to carbon include two, four and six electron bonds. C . . . . atomic state C : : : C 4 single bonds C :: C= 2 single and one double bond C ::: : C one single and one triple bond
Background image of page 4
Alkenes: The Carbon-Carbon Double Bond Consider two carbon atoms coming together to share 4 valence electrons in a covalent bond: Lewis Structures C . . . . C . . . . C . . . C . . . . . a two electron bond C . . . C . . . . . a four electron bond The remaining valence electrons are used to form covalent bonds to other atoms or groups. In ethene, C 2 H 4 , four hydrogen atoms are bonded to the carbons. H:C::C:H H : H or H-C=C-H H H
Background image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Geometry of Ethene Ethene is a planar molecule with the internal bond angles shown below. C C H H H H 121 o 118 o This trigonal planar arrangement of the bonding electrons is predicted by the valence shell electron pair repulsion theory .
Background image of page 6
The Carbon-Carbon Double Bond The carbon-carbon double bond results from valence level orbital interaction between two sp 2 hybridized carbons as shown below. In this picture, the two atomic centers are brought together along an axis that allows overlap of sp 2 hybrid orbitals.
Background image of page 7

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 8
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 08/06/2011 for the course CHEM 221x taught by Professor Broyer during the Summer '11 term at USC.

Page1 / 25

Lec 4 - Molecular Geometry and Polarity Chem 221 Thursday July 14 2011 The Structure of Ethane Ethane C2H 6 is the second member of the alkane

This preview shows document pages 1 - 8. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online