- #1
fomenkoa
- 47
- 0
Hey everyone
I am confused as to the structure of a heme molecule. A picture of it is shown here:
http://en.wikipedia.org/wiki/Image:Heme.png
I understand the heme group is largely a porphyrin molecule. The 4 Nitrogens are coordinate-covalently bound to the central Iron atom. The top-left Nitrogen in the diagram checks out. It has 5 valence electrons (3 bonded to the two carbons and 2 in the coordinate bond)
However, my question is : what about the top right Nitrogen? It seems to only have 4 valence electrons.
Does this have to do with the resonance of the carbon rings and how the double bonds can move around? Any help would be appreciated!
Also, Where are the valence electrons of the Iron since it doesent contribute to the coordinate bonds? Are they just lone pairs then?
Anton
I am confused as to the structure of a heme molecule. A picture of it is shown here:
http://en.wikipedia.org/wiki/Image:Heme.png
I understand the heme group is largely a porphyrin molecule. The 4 Nitrogens are coordinate-covalently bound to the central Iron atom. The top-left Nitrogen in the diagram checks out. It has 5 valence electrons (3 bonded to the two carbons and 2 in the coordinate bond)
However, my question is : what about the top right Nitrogen? It seems to only have 4 valence electrons.
Does this have to do with the resonance of the carbon rings and how the double bonds can move around? Any help would be appreciated!
Also, Where are the valence electrons of the Iron since it doesent contribute to the coordinate bonds? Are they just lone pairs then?
Anton