48 Mr. W. Sutherland on the Fundamental 



Thomsen's structure for HON. Our equation for cyanogen 

 is : — 



/(C-0) + 2/(0 ;N) + 2«= 11-1, .... (47) 



.'■". 2/(C;N) + 2a=-3\L, .-. /(CiN)+«=-l-5. 



Here we have another value for/(0j N) -fa, showing again 

 evidence of a subsidiary action, but perhaps the experimental 

 error does not allow of a very definite measure of it. To a 

 first approximation then we can write 



/(C;N)+*=0. 



(48) 



9. Amines. — In the values of p + ad for the amines, 

 Thomsen finds the effect of CH 2 rather larger than the 44' 2 

 taken as the normal amount of it, and in this respect the 

 amines agree with the halogen compounds and the oxides, 

 but it is probable that slight experimental error is responsible 

 in all these cases for the slight excess in the value for CH 2 . 

 The values of p + ad for a monamine and the isomeric diamine 

 and triamine are not equal, nor should they be expected to be 

 so, seeing that these are not strict isomers, as their structure 

 involves the displacement of one, two, and three atoms of H 

 from ammonia. The thermal effect of these displacements is 

 the most important point in the thermochemistry of the 

 amines, and is shown in the column of differences in the 

 following table of values of p +ad : — 



NEL 



11-3 



CH 3 NH 46-8 



(CH 3 ) 2 NH 87^7 



(CH 3 ) 3 N 128-7 



Diff. 

 355 

 41-0 

 41-0 



NH 3 113 



C 2 H 5 JSH 2 92-5 



(C 2 BVym 1799 



(0 3 H 5 ) 3 N 268-3 



Diff. 

 81-2 



87'4 

 88-3 



The first substitution of CH 3 for H in NH 3 seems to be 

 accompanied by a smaller thermal effect than the second and 

 third, and on account of this fact and the values which he has 

 already assigned to the junctions, Thomsen proposes for the 

 mono-, di-, and tri-methyl amines the peculiar constitutions 



H 2 C^ H 3 C% 



H 2 C :NH 3 , "NH 2 , and H 3 0— NH. From our point of 



H 3 C/ H 3 C/ 



view the difference between the first and the second and third 

 substitutions of CH 3 for H in ammonia is due to the mutual 

 effect of unconnected atoms to be investigated in the second 



