Functional group geometry

ORGANIC MOLECULE GEOMETRY
Molecular Geometry
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Functional Groups and Molecular Geometry

Molecular geometry is associated with the specific orientation of bonding atoms. For organic molecules, we will observe the same types of geometry - linear, trigonal planar, tetrahedral, trigonal pyramid, and bent. When a molecule consists of many atoms, each carbon, oxygen, or nitrogen atom may be the center of the one of the geometries previously listed. The molecule as a whole will be the sum of all of the individual geometries to give an overall shape to the molecule. TAKE A QUIZ on the molecular geometry of the functional groups.

R = any number carbons in a hydrocarbon chain
*CHIME plug-in required to view these images.

Functional
Group
Name
General
Structure
Structure

and Molecular Geometry
Name
Graphic
Chime*

Alkane
CH₃CH₂CH₃

All carbons have single bonds therefore the molecular geometry is TETRAHEDRAL. See alkanes.

Chime

Alkene
CH₂=CHCH₃

The main centers of interest are the carbons of the double bond. Each carbon is the center of a TRIGONAL PLANAR geometry. This portion of the molecule is flat, with bond angles of 120 degrees. See alkenes.

Chime

Alkyne
CH=CCH₃

The main centers of interest are the carbons of the triple bond. Each carbon is the center of a LINEAR geometry. This portion of the molecule is in a straight line, with bond angles of 180 degrees. See alkynes.

Chime

Alcohol
R-OH
CH₃CH₂CH₂OH

There are several centers of interest. Each carbon with all single bonds is the center of a tetrahedral geometry.

The center of the ether functional group is the oxygen. As in the water molecule there are two lone pairs of electrons on the oxygen in addition to the single bonds (invisible in the graphic), which give an electron pair geometry of tetrahedral.

This forces the molecular geometry on the alcohol oxygen to be BENT. This portion of the molecule is flat, with bond angles of 109 degrees.

Chime

Ether
R-O-R
CH₃CH₂O-CH₂CH₃

There are several centers of interest. Each carbon with all single bonds is the center of a tetrahedral geometry.

The center of the ether functional group is the oxygen. As in the water molecule there are two lone pairs of electrons on the oxygen in addition to the single bonds (invisible in the graphic), which give an electron pair geometry of tetrahedral.

This forces the molecular geometry on the ether oxygen to be BENT. This portion of the molecule is flat, with bond angles of 109 degrees.

Chime

Aldehyde
There are several centers of interest. Each carbon with all single bonds is the center of a tetrahedral geometry.

The center of the aldehyde functional group is the carbon double bond oxygen.

With three atoms attached to this carbon, the molecular geometry is TRIGONAL PLANAR. This portion of the molecule is flat, with bond angles of 120 degrees. See formaldehyde.

Chime

Ketone
There are several centers of interest. Each carbon with all single bonds is the center of a tetrahedral geometry.

The center of the ketone functional group is the carbon double bond oxygen.

With three atoms attached to this carbon, the molecular geometry is TRIGONAL PLANAR. This portion of the molecule is flat, with bond angles of 120 degrees. See formaldehyde

Chime

Acid
There are several centers of interest. The carbon with all single bonds is the center of a tetrahedral geometry.

The center of the acid functional group is the carbon double bond oxygen.

With three atoms attached to this carbon, the molecular geometry is TRIGONAL PLANAR. This portion of the molecule is flat, with bond angles of 120 degrees.

An additional molecular geometry is centered on the oxygen of the - OH group. This is BENT.

Chime

Ester

There are several centers of interest. The two carbons with all single bonds is the center of a tetrahedral geometry.

The center of the ester functional group is the carbon double bond oxygen.

With three atoms attached to this carbon, the molecular geometry is TRIGONAL PLANAR. This portion of the molecule is flat, with bond angles of 120 degrees.

An additional molecular geometry is centered on the oxygen with all single bonds. This is BENT.

Chime

Amine
R-NH₂
or
R-NH-R
CH₃CH₂CH₂NH₂

There are several centers of interest. Each carbon with all single bonds is the center of a tetrahedral geometry.

The center of the amine functional group is the nitrogen. As in the ammonia molecule there is one lone pair of electrons on the nitrogen in addition to the single bonds (invisible in the graphic), which give an electron pair geometry of tetrahedral.

This forces the molecular geometry on the amine nitrogen to be a TRIGONAL PYRAMID. This portion of the molecule is NOT flat, with bond angles of 109 degrees.

Chime

Amide

There are several centers of interest. Each carbon with all single bonds is the center of a tetrahedral geometry.

The center of the amide functional group is the carbon double bond oxygen and the nitrogen.

With three atoms attached to this carbon, the molecular geometry is TRIGONAL PLANAR. This portion of the molecule is flat, with bond angles of 120 degrees.

An additional molecular geometry is centered on the nitrogen through an exceptional circumstance of the bonding. This is BENT and also flat as an extension of the trigonal planar geometry.

Chime

Functional Groups and Molecular Geometry Molecular geometry is associated with the specific orientation of bonding atoms. For organic molecules, we will observe the same types of geometry - linear, trigonal planar, tetrahedral, trigonal pyramid, and bent. When a molecule consists of many atoms, each carbon, oxygen, or nitrogen atom may be the center of the one of the geometries previously listed. The molecule as a whole will be the sum of all of the individual geometries to give an overall shape to the molecule. TAKE A QUIZ on the molecular geometry of the functional groups.
R = any number carbons in a hydrocarbon chain *CHIME plug-in required to view these images.
Functional Group Name	General Structure	Structure and Molecular Geometry	Name Graphic Chime*
Alkane		CH₃CH₂CH₃ All carbons have single bonds therefore the molecular geometry is TETRAHEDRAL. See alkanes.	Chime
Alkene		CH₂=CHCH₃ The main centers of interest are the carbons of the double bond. Each carbon is the center of a TRIGONAL PLANAR geometry. This portion of the molecule is flat, with bond angles of 120 degrees. See alkenes.	Chime
Alkyne		CH=CCH₃ The main centers of interest are the carbons of the triple bond. Each carbon is the center of a LINEAR geometry. This portion of the molecule is in a straight line, with bond angles of 180 degrees. See alkynes.	Chime
Alcohol	R-OH	CH₃CH₂CH₂OH There are several centers of interest. Each carbon with all single bonds is the center of a tetrahedral geometry. The center of the ether functional group is the oxygen. As in the water molecule there are two lone pairs of electrons on the oxygen in addition to the single bonds (invisible in the graphic), which give an electron pair geometry of tetrahedral. This forces the molecular geometry on the alcohol oxygen to be BENT. This portion of the molecule is flat, with bond angles of 109 degrees.	Chime
Ether	R-O-R	CH₃CH₂O-CH₂CH₃ There are several centers of interest. Each carbon with all single bonds is the center of a tetrahedral geometry. The center of the ether functional group is the oxygen. As in the water molecule there are two lone pairs of electrons on the oxygen in addition to the single bonds (invisible in the graphic), which give an electron pair geometry of tetrahedral. This forces the molecular geometry on the ether oxygen to be BENT. This portion of the molecule is flat, with bond angles of 109 degrees.	Chime
Aldehyde		There are several centers of interest. Each carbon with all single bonds is the center of a tetrahedral geometry. The center of the aldehyde functional group is the carbon double bond oxygen. With three atoms attached to this carbon, the molecular geometry is TRIGONAL PLANAR. This portion of the molecule is flat, with bond angles of 120 degrees. See formaldehyde.	Chime
Ketone		There are several centers of interest. Each carbon with all single bonds is the center of a tetrahedral geometry. The center of the ketone functional group is the carbon double bond oxygen. With three atoms attached to this carbon, the molecular geometry is TRIGONAL PLANAR. This portion of the molecule is flat, with bond angles of 120 degrees. See formaldehyde	Chime
Acid		There are several centers of interest. The carbon with all single bonds is the center of a tetrahedral geometry. The center of the acid functional group is the carbon double bond oxygen. With three atoms attached to this carbon, the molecular geometry is TRIGONAL PLANAR. This portion of the molecule is flat, with bond angles of 120 degrees. An additional molecular geometry is centered on the oxygen of the - OH group. This is BENT.	Chime
Ester		There are several centers of interest. The two carbons with all single bonds is the center of a tetrahedral geometry. The center of the ester functional group is the carbon double bond oxygen. With three atoms attached to this carbon, the molecular geometry is TRIGONAL PLANAR. This portion of the molecule is flat, with bond angles of 120 degrees. An additional molecular geometry is centered on the oxygen with all single bonds. This is BENT.	Chime
Amine	R-NH₂ or R-NH-R	CH₃CH₂CH₂NH₂ There are several centers of interest. Each carbon with all single bonds is the center of a tetrahedral geometry. The center of the amine functional group is the nitrogen. As in the ammonia molecule there is one lone pair of electrons on the nitrogen in addition to the single bonds (invisible in the graphic), which give an electron pair geometry of tetrahedral. This forces the molecular geometry on the amine nitrogen to be a TRIGONAL PYRAMID. This portion of the molecule is NOT flat, with bond angles of 109 degrees.	Chime
Amide		There are several centers of interest. Each carbon with all single bonds is the center of a tetrahedral geometry. The center of the amide functional group is the carbon double bond oxygen and the nitrogen. With three atoms attached to this carbon, the molecular geometry is TRIGONAL PLANAR. This portion of the molecule is flat, with bond angles of 120 degrees. An additional molecular geometry is centered on the nitrogen through an exceptional circumstance of the bonding. This is BENT and also flat as an extension of the trigonal planar geometry.	Chime