Interaction of Nitric Oxide with Silver Nitrate. 



By 



Edward Divers, M. D., D. Sc, F. R. S., Prof., 

 Im})ei-ial University, Tokyo. 



Having reason to think that silver nitrate might interact 

 with nitric oxide if heated in it, and there being no informa- 

 tion obtainable on the point, I have been induced to make 

 some experiments with silver nitrate, as well as other nitrates, 

 and nitric oxide. 



First, something had to be ascertained of the behaviour of 

 silver nitrate when heated alone. Heated for fifteen minutes 

 in dry air or carbon dioxide, it suffers no chemical change 

 until the temperature is close to the melting point of sulphur 

 (444°), and its slight decomposition at that temperature, being 

 accompanied by its action upon the glass, may be due to that 

 action. A minute quantity of oxygen seems to be liberated, and 

 there is a very slight greying of the faintly yellow liquid. On 

 cooling and dissolving, there is slight turbidity from the pre- 

 sence of silver, and a trace of nitrite can be detected. Only 

 at a much higher temperature does the salt decompose with 

 free effervescence, and then nitric peroxide accompanies the 

 oxygen, and silver is deposited. Even then, nitrite is present 

 in the mass only in very small quantity at any time, being 

 never enough to remain insoluble when the nitrate is dissolved 

 in a little water. This is sufficient, however, to show that the 

 primary decomposition of silver nitrate, by heat alone, is into 

 silver nitrite and oxygen ; since the instability of silver nitrite 

 at much lower temperatures, though diminished by the presence 



