what is the molecular geometry of niacin? C6H5NO2
The ring is planar.
http://en.wikipedia.org/wiki/File:Niacin-3D-balls.png
To determine the molecular geometry of a compound, we need to know the Lewis structure and the number of electron groups around the central atom.
First, let's determine the Lewis structure of niacin (C6H5NO2):
1. Count the total number of valence electrons:
Carbon (C) has 4 valence electrons x 6 atoms = 24 electrons
Hydrogen (H) has 1 valence electron x 5 atoms = 5 electrons
Nitrogen (N) has 5 valence electrons x 1 atom = 5 electrons
Oxygen (O) has 6 valence electrons x 2 atoms = 12 electrons
Total valence electrons = 24 + 5 + 5 + 12 = 46 electrons
2. Place the atoms in the structure, with the least electronegative element (carbon) in the center:
H
|
H-C-H
| |
H-C -C -C-H
| |
H N(=O)-O
|
O
3. Distribute the remaining electrons around the atoms. Start by completing the octets of the terminal atoms (hydrogen and oxygen):
H
|
H-C-H
| |
H-C -C -C-H
| |
H N(=O)-O
|
O
4. Distribute the remaining electrons to complete the octet of the central atom (nitrogen):
H
|
H-C-H
| |
H-C -C -C-H
| |
H N(=O)-O
||
O
5. Count the electron groups around the central atom:
Nitrogen has 3 bonded atoms (C, H, and O) and 1 lone pair of electrons, so there are a total of 4 electron groups around the nitrogen atom.
6. Determine the molecular geometry based on the number of electron groups:
With 4 electron groups, the molecular geometry of niacin (C6H5NO2) around the central nitrogen atom is trigonal pyramidal.
Therefore, the molecular geometry of niacin is trigonal pyramidal.