The hexammine salts are formed by the oxidizing action of air on dilute ammoniacal solutions of cobaltous salts, especially in presence of a large excess of ammonium chloride.
Acid oxidizing agents, however, completely destroy them.
The mono-amino derivatives or eurhodines are obtained when the arylmonamines are condensed with orthoamino zo compounds; by condensing quinone dichlorimide or para-nitrosodimethyl aniline with monamines containing a free para position, or by oxidizing ortho-hydroxydiaminodiphenylamines (R.
Cadmium salts can be recognized by the brown incrustation which is formed when they are heated on charcoal in the oxidizing flame of the blowpipe; and also by the yellow precipitate formed when sulphuretted hydrogen is passed though their acidified solutions.
Molybdenum trioxide, Mo03, is prepared by oxidizing the metal or the sulphide by heating them in air, or with nitric acid.