294 PHENOL. 



quickly, with a solution of sodium carbonate. Yellow, 

 shiny prisms or laminae, of an exceedingly bitter taste. 

 Fuses at 122.5 ; when carefully heated it is sublimable ; 

 detonates when rapidly heated. Difficultly soluble in 

 cold water, more easily in hot water, and still more 

 easily in alcohol. Dyes wool and silk yellow. Strong 

 acid. "With bases it yields yellow salts that crystal- 

 lize well. The salts explode violently when heated, 

 and some of them by percussion. 



Potassium picrate, C 6 H 2 (1TO 2 ) 3 .OK, crystallizes in 

 long needles, very difficultly soluble in warm water. 

 The sodium, ammonium, and barium salts are easily 

 soluble in water. 



Picrocyamic acid (Isopurpuric acid), C 8 H 5 N 5 6 . 

 The free acid cannot be prepared. The potassium salt 

 C 8 H 4 E" 5 6 .K is produced by dropping a hot solution of 

 picric acid (1 part in 9 parts of water) into a warm 

 (60) solution of potassium cyanate (2 parts of potas- 

 sium cyanate in 4 parts of water). Brownish-red 

 scales with a green metallic lustre. Sparingly soluble 

 in cold water, soluble in hot water and in alcohol, form- 

 ing a deep-red solution (test for hydrocyanic acid and 

 cyanides). Detonates with a loud report when heated. 



By the action of nitric acid on chlor-, brom-, and 

 iodophenols there are produced nitrochlorine, nitrobro- 

 mine, and nitroiodine substitution-products, of which a 

 very large number is known. 



Amido compounds. Amidophenol, C 6 H 4 (NH 2 ).OH, 

 and the isomeric compound, isoamidophenol (ortho- 

 amidophenol), are produced by the reduction of the 

 corresponding nitro-compounds, most readily by means 

 of tin and hydrochloric acid. Amidophenol crys- 

 tallizes in colorless, rhombic scales; isoamidophenol, 

 which is also produced by heating amidosalicylic acid, 

 forms colorless needles, that turn brown easily. Both 

 compounds are difficultly soluble in cold water, more 

 readily in alcohol ; fuse at 170, and yield with acids 

 salts that crystallize well. Dinitroamidophenol (Picra- 



