HYDROGEN BONDING 83 



only one oxygen atom, so that each oxygen is accepting two hydrogen bonds, 

 and this may be why they are somewhat longer. 



In other amides the distances are the same as in t'lese zwitter-ion amino 

 acids. 



Dr. Jack D. Dunitz (National Institutes of Health) : What is your opinion 

 concerning the structure of oximes? In these structures of binding by oxygen 

 one has to make a choice between, on the one hand, :n orthodox chemical 

 structure C=N— OH with an angle of about 70° between the OH and its hy- 

 drogen bonded nitrogen, or between an unorthodox chemical structure 

 C^N+H — 0~ and a normal angle of about 105°. Which do your prefer? 



Professor Donohue: A choice between 70° and 105°? Obviously, we will 

 take the 105°. Somebody should get out his Geiger counter and find the hydro- 

 gen atom; that would lay this question to rest. I might add that in the case of 

 one of these oximes there is an error in the paper. The angles as quoted by the 

 author are incorrect. Both relevant angles are near to 90°, so that you cannot 

 make the choice. If one of them is 70° and the other is 110° then you could make 

 the choice, but if you recalculate this yourself you will find 85° and 95°, which 

 are about equally acceptable. 



