290 NITROGEN. 



tion of the nitrous acid is always decomposed into nitric oxide 

 gas and nitric acid.* 



It must be admitted that some obscurity still hangs over the 

 nature of this acid, when uncombined, the formation of the 

 nitrites by Gay-Lussac's process appearing to be incompatible 

 with the properties ascribed to the free acid by Dulong. Its 

 tendency to combine with acids has already been noticed as as- 

 similating this compound of nitrogen to arsenious acid and the 

 oxide of antimony (page 146.) 



PEROXIDE OF NITROGEN. 



Syn. NITROUS ACID (Turner,) HYPONITRIC ACID, NITROUS 

 GAS (Berzelius.) Eg. 5/7 or 46.2; NO 4 ; density 3181.2; | | 'j. 



This compound forms the principal part of the ruddy fumes 

 which always appear on mixing nitric oxide with air. As it 

 cannot be made to unite either directly or indirectly with bases, 

 and has no acid properties, any designation for this oxide of 

 nitrogen which implies acidity should be avoided, and the name 

 nitrous acid in particular, which is applied on the continent to 

 the preceding compound. The name peroxide of nitrogen is 

 more in accordance with the rules generally followed in naming 

 such compounds. 



Preparation. When 4 volumes of nitric oxide and 2 of 

 oxygen, both perfectly dry, are mixed, this compound is alone 

 produced, and the 6 volumes of mixed gases are condensed into 

 2 volumes, which may be considered the combining measure of 

 peroxide of nitrogen. The weight of 1 volume, or the density 

 of this gas must therefore be 



1039.x 34+ 1102.6x2 01 Q1 ct 



2 Olol.Z. 



The peroxide of nitrogen is also contained in the coloured and 

 fuming nitric acid of commerce, and may be obtained in the 

 liquid condition, by gently warming that acid, and condensing 

 the vapour which comes over, by transmitting it through a glass 

 tube surrounded by ice and salt. But it is prepared with most 

 advantage from the nitrate of lead, the crystals of which, after 

 being pounded and dried, are distilled in a retort of stoneware 



* An. de Ch. et dc Ph. t. 45, p. 284. 



