THIONURIC ACID. 55 



Carbon, . 17-84 or 8 atoms =6 or per cent. 17-45 



Hydrogen, . 4-90 or 13 atoms = 1-625 ... 4-72 



Azote, . 26-01 or 5 atoms = 8-750 ... 25-45 



Oxygen, . 22-78 or 8 atoms = 8-000 ... 23-28 



Sulphuric acid, 28-47 or 2 atoms = 10-000 ... 29-10 



100 34-375 100 



If from the preceding constituents, C 8 H 13 Az 5 O 8 + 2 (S O 3 ) 

 We subtract 1 atom thionuric acid, C 8 H 5 Az 3 O 6 + 2 (S O 3 ) 



There will remain, . . H 8 Az 2 O 2 



From this remainder subtract 2 atoms 



water, H 2 O 2 



There will remain, . . H 6 Az 2 which is equal 



to 2 atoms ammonia. 



So that thionurate of ammonia consists of 



1 atom thionuric acid, C 8 H 5 Az 3 O 6 2 (S O 3 ) 



2 atoms ammonia, . H 6 Az 2 



2 atoms water, . H 2 O 2 



C 8 H 13 Az 5 O 8 + 2 (S O 3 ) 



We see that hydrated thionuric acid contains two atoms water, 

 or it is C 8 H 7 Az 3 O 8 + 2 (S O 3 ) = 32-125. 



Thionurate of lime is obtained by mixing together hot solu- 

 tions of thionurate of ammonia and nitrate of lime. It separates 

 under the form of small short prisms, having a satiny lustre. It 

 is composed of 



1 atom thionuric acid, . 29-875 



2 atoms lime, . . 7-000 



36-875 



Thionurate of zinc constitutes small aggregated crystals, which 

 have a lemon- yellow colour. It is very soluble in water, and is 

 obtained by mixing a salt of zinc with a solution of thionurate of 

 ammonia. 



A hot solution of thionurate of ammonia mixed with sulphate 

 of copper gives a brown precipitate, approaching to yellow, which 

 is obviously protoxide of copper. By the action of heat, it dis- 

 solves completely into a yellowish-brown liquid, and separates 

 again on cooling in an amorphous state. 



