98 AMMONIA. 



It enters into a greater number of combinations tban perhaps 

 any other base whatever. I propose in this section to give 

 merely a catalogue of the most important of these compounds, 

 and, at the same time, to explain the views at present entertained 

 respecting their nature. 



Ammonia has been long known to be a compound of azote 

 and hydrogen. But azote and hydrogen are at present con- 

 ceived to be capable of uniting in three different proportions. 



1. The first, called amide, is a compound of one atom azote, 

 and two atoms hydrogen, Az H 2 2. It is considered as the 

 radical of ammonia, and has not hitherto been obtained in an 

 isolated form. It is not a base ; but is capable of combining 

 with bases, and seven of such compounds are known. 



2. The second compound of azote and hydrogen is ammonia. 

 It consists of one atom of azote combined with three atoms am- * 

 monia, Az H 3 = 2-125. It is a powerful base, and readily com- 

 bines with and neutralizes acids. 



3. The third compound of azote and hydrogen is called am- 

 monium. It is a compound of one atom of azote with four atoms 

 hydrogen, Az H 4 = 2-25. It possesses the character of a metal, 

 and is capable of combining with metals. Hitherto it has not 

 been obtained in an isolated state. But all the ammoniacal salts 

 containing oxygen acids are considered at present as compounds 

 of the acid and oxide of ammonium. 



Let us take a view of the compounds which these three modi- 

 fications of ammonia are capable of forming. 



I. AMIDES. 



1. Amide of potassium, . Az H 2 -f- K r= 7 



2. Amide of sodium . Az H 2 -f Na = 5 



3. Amide of mercury, . Az H 2 + Hg 14-5 

 White precipitate, Az H 2 Hg -f Chi. Hg = 31-5 (Kane) ob- 

 tained by precipitating corrosive sublimate by caustic ammonia. 



When white precipitate is treated with caustic potash, we ob- 

 tain a yellow powder composed of Az H 2 Hg + 2 Hg O -f 

 Chl. Hg = 58-5 (Kane.) 



A number of other complex compounds have been analysed by 

 Dr Kane of Dublin. 



4. Amide of copper and hyposulphate of ammonium, Az H 2 

 Cu + (S 2 O 5 ) (Az H 4 O) = 18-25. 



