Specification :

Flashing brown paste. Slightly soluble in cold water, soluble in hot water was blue, soluble in alcohol, blue. Case of concentrated sulfuric acid was brown, yellow and red was diluted in the concentrated nitric acid was olive green. Its solution plus sodium hydroxide solution was reddish brown. Cotton dyed material on the drops of 10% sulfuric acid changes on the light brown yellow, dripping red on 10% sodium hydroxide become yellow, drop on the acidic stannous chloride solution, red yellow change.